Circulation and Gas Exchange

Question 1

Importance of Diffusion

Answer 1

• essential for all organisms is the ability to move substances btwn cells and their surrounding environment; which is accomplished through the process of diffusion
• diffusion = passive, due to concentration gradient of high concentration to low concentration; its efficiency is based on proximity so distance plays a role
• for larger organisms, cannot rely solely on diffusion for exchange to occur, will have another mechanism while smaller organisms can rely solely on diffusion
• regardless diffusion is super important to exchange

Question 2

Gastrovascular Cavities

Answer 2

• Cnidarian and flatworm are some animals that lack circulatory system
• instead they have gastrovascular system which incorporates digestion with distribution of substances throughout the body
• want it to be relatively thin
• body construct and organization helps to support cavity as primary means of circulation

Question 3

Open and Closed Circulatory Systems:

Answer 3

Circulatory system, they are going to contain
some type of circulatory fluid
Some type of vessels
Help to direct that circulatory fluid to diff regions of the body
Muscular pump/heart
Applicable to both open and closed circulatory system
Compare these two types of circulatory system
Open circulatory system:
No distinction that is made between the circulating fluid and the extracellular fluid (fluid surrounding the cells of the body tissue)
They are referred to a s hemolymph
The heart is going to play a role in pumping the hemolymph through the vessels, and vessels will lead out into body cavities
Essentially hemolymph that will enter sinuses, fluid will then drain back into essential cavities, head towards heart and will continue with that process of exchange
Closed system:
Circulating fluid always stay enclosed within vessels that will help facilitate movement either towards the heart of away from the heart
Heart plays a role in pumping the circulatory fluid within the organism
heart pump blood in a direction that lets it go to smaller vessels that provides an opportunity for exchange of substances in different areas of the earthworm body
Blood that will continue through that circuit and go back to the heart will continuous distribution
Auxiliary hearts/psdedo hearts and a closed circuit in which there’s a dorsal vessel, running on the top portion of earthworm
ventral vessel that runs in the bottom half of earthworm
Key difference between open and closed is how these interconnecting vessels are organisms
Open: these interconnected vessels, while they connected with each other eventually open up to that sinus
Closed circuit: these connected vessels stay completed closed
Definition perspective, while we’re saying the circulating fluid is always enclosed within vessels, don’t want to imply that circuiltory fluid is incapable of it exciting in some way bc we will see some examples of that as we progress forward

Question 4

Human circulatory system

Answer 4

For humans and other vertebrates:
Closed circulatory system called cardiovascular system
Cardiovascular system has three major types of blood vessels:
Arteries, veins, capillaries
When it comes to movement of that circulating fluid, want it to be unidirectionally
Want it to go directly where it needs to go, no turbulence by backflow
This helps to increase efficiency of moving that circulatory fluid throughout our bodies

Question 5

Oxylitol: example of amphibian who uses gills

Answer 5

Gills accomplishes the exchange of substances with its environment that an animal needs to survive

• gills are specialized for exchange in certain animals
• O2 going to diffuse in from water into blood vessels, and CO2 (waste buildup) is going to diffuse out of blood and into surrounding environment, meaning the water
• form and function important here!
• form is the feathery nature of gills, and these extensions helps to increase surface area, and thus increases opportunity for exchange to take place (wider)

Question 6

Single Circulation:

Answer 6

ex of a closed circulatory system that is single circulation = fish
-fish has a true chamber pump heart, one atrium, and one ventricle

• blood is going to be pumped out of ventricle (that’s in the heart) and goes through the artery away from the heart and towards gill capillaries
• gill capillaries is where we have oxygenation of blood, so we go from oxygen poor blood (blue) to oxygen rich blood (red) as we go through gills capillary bed
• now this oxygen rich blood goes through body capillaries and distributes oxygen and nutrients to the rest of the body; this results in oxygen poor blood again (depleted of oxygen)
• this oxygen poor blood will go to the veins, and eventually drop down into atrium in the heart for process to start again with the ventricle

Question 7

Limitations to Single Circuit

Answer 7

• single circuit loop is limiting as when blood passes through the gill capillaries to become oxygen rich, blood pressure drops significantly in the gill capillaries
• this will slow down circulation that is going towards the rest of the body (towards body capillaries), thus it limits oxygen delivery to tissues (longer time to get there)

Question 8

Double Circulation- amphibian (two atriums, one ventricle)

Answer 8

in double circulation, there is going to be a region that is oxygen poor and a region that is oxygen rich in the heart
-when it comes to amphibian heart, it has three chambers; two atrium, right and left, and a single ventricle
-right hand side of chamber with right atrium has poor oxygen
left hand side with left atrium has rich

Right chamber: right atrium will receive deoxygenated blood from the systemic circuit (body) from the vessels and the deoxygenated blood will be pumped out via the ventricle to the artery to the pulmocutaneous circuit (lungs and skin capillaries) for the deoxygenated blood to become oxygenated.
-This oxygenated blood goes to the left atrium via vessels into the left chamber

Left atrium: will receive oxygenated blood from the lung and skin capillaries and the ventricle will pump out the oxygenated blood to the systemic capillaries (body) via the artery

• this will provide the body oxygen, and the blood will thus become deoxygenated as body will use the oxygen from blood
• this deoxygenated blood will go through vessels to go to left atrium in left chamber, and process repeats itself
• Since there is only one ventricle, doesn’t have the means the separate blood content completely within the ventricle sphere
• double circulation is able to maintain a high blood pressure than single circulation as it has an opportunity to reestablish the pressure gradient when we have blood entering back into heart

Question 9

Double circulation: mammals (2 atrium, 2 ventricle)

Answer 9

Heart itself has 4 chambers

• two atriums (left and right)
• two ventricles (left and right)

Contrast to the double circulation, when we look along the midline of the heart, we no longer see purple bc we have tissue that is going to partition off that ventricle
-thus we are able to keep pulmonary and systemic circuit completely separate; which increases efficiency

Mammals are endotherms, regulate their own temp, and thus they need a high metabolic rate; having increased efficiency due to structure of the heart, having four chambers, means it can circulate faster as it is able to maintain blood pressure super well, so it can use oxygen more in metabolism, and thus regulate its own temp as needed as it is an endotherm

Question 10

What do blood vessels do?

Answer 10

Transport
Regulation of blood flow
Secreting a variety of diff chemicals
Control of blood pressure
Should be described based on the direction of blood flow rather the type of oxygen content
When we say something is going to be an artery, what we’re saying is that these are efferent vessels
Carrying blood away from the heart
If they are veins, those are afferent, and they will be carrying blood back towards the heart

Question 11

Artery:

Answer 11

Described as distribution system bc they are going to distribute blood all over body
There are diff types of them, vary depending on the layers of tissues that they have, diameter that they posses into their opening (lumen)
Electric arteries (biggest diameter)
Are conducting
Ex: aorta, pulmonary trunk
These are going to help to provide a major force of blood movement through the body
Conducting arteries
These can a interstate highway, they serve as a major thoroughfare for blood flow, from the heart to nan artery of a smaller size
Going to be withstanding a ton of pressure due to their proximity towards the heart, want them to resist that level of pressure a certain extent so that we don’t have abrupt changes with respect to blood flow with every contraction and relaxation event within the heart
Muscular arteries: (medium diameter)
Distributing arteries
Highway analogy: exit ramps
Exiting off in order to supply blood to a specific area of the body
Ex: ephemeral artery
More active in the process of vasoconstriction; which is going to change the amount of blood that can flow to diff areas of the body
Do this more so than that of elastic arteries
Arterioles arteries: (small diameter)
Resistance arteries
Thin to control blood flow to tissues
Site in which we feed into these capillaries bed

Question 12

Veins

Answer 12

Going to be collection system bc they are going to drain the body in diff regions
Venule:
Drain the capillary bed
Veins will ultimately return blood to the heart
Collapsed organization in comparison to arteries (which are more structured)
Bc they are serving as reservoirs
Not going to need to withstand the same amount of pressure that is seen within the artery, so we don’t have to worry about the possibility of them bursting with the high pressure they would have experienced if they were on the side of the heart that is focused on distribution
Have a larger lumen
Allows for very little resistance to blood flow when we compare to arteries

Question 13

Capillaries:

Answer 13

Serve as an opportunity for exchange to take place between vessels that have been carrying blood in diff directions relative to the heart
Capillary bed: described as exchange vessels
Color shifting to purple bc it is a site of which vessels of varying oxygen content will have the opportunity to merge with one another

Question 14

Coordinated cycles of heart contraction drive double circulation in mammals

Answer 14

mammalian cardiovascular system is our focus

• the way it is organized is meant to help meet the demands for oxygen as O2 is used in last portion of cellular respiration to make ATP
• ATP is used as energy to drive tons fo events for the body

Question 15

Mammalian Circulation: Steps 1-11

Answer 15

Overview of mammalian circulation
Cardiovascular system has two major divisions
Pulmonary circuit
Bring blood to lungs for gas exchange to occur
Go from oxygen poor to oxygen rich and then return it to the heart
Systemic circuit:
Supplies blood to every organ of the body, including some parts of the lungs that need oxygen rich blood to carry out their own needs and the walls of the heart itself
Step one: within the right ventricle
Our blood here is blue, it is oxygen depleted/poor
Blood that is found in right ventricle is going to make its way out via arrow, towards the region
Valve found this site and valve needs to be in open state in order for that oxygen poor blood to exit out
Transition from one to two
Step two: pulmonary trunk
Not shown within this illustration
Major vessel (artery) that is going to be receiving the oxygen poor blood that gets pumped out of the right ventricle
Pulmonary trunk is going to branch
We see branching towards the right and the left
Oxygen poor blood heading towards the lungs
Right and left lung
Pulmonary circulation at this point
When we get to that location, we will find branching of our arteries into smaller vessels until we ultimately reach capillaries
Step three: capillary bed
From the pulmonary trunk, we will head towards the right pulmonary artery and left pulmonary artery until we get to capillaries of right and left lung
At this location, at our capillary bed, we will have an exchange
Diffusion of our substances
We will have movement of our oxygen into these vessels (capillaries)
Oxygen source coming from lungs
Through that process, we will see a shift from a blue state to a red state
Now we go from pulmonary arteries to our right pulmonary vein and our left pulmonary vein
Veins will go towards the heart, so now these veins will be making their way back towards the heart, we were we can reestablish pressure with the pumping our heart
Step four: left atrium
Received blood from the right and left pulmonary veins
Collect that blood and it’s going to drop down into step 5 (left ventricle)
In order for it to go to step 5, there is a valve that will separate the atrium from the ventricle
In order for flow to occur, that valve needs to be in an open state
Step 5: left ventricle
Oxygen rich blood is going to get pumped out of ventricle and is going to make its way through the valve (diff valve than in step 4) Valve is what separates the content of blood found in left ventricle with the aorta
Step 6, 7, 8: Aorta leading to arteries going to capillaries of head and forelimbs, and abdominal organs and hind limbs
The aorta is going to help us distribute blood to the rest of the body through systemic circulation
They will branch into tons of different arteries
They will go up towards the top of the body, and to the bottom, and eventually meet diff capillary beds
Capillary beds at head and forelimbs, and abdominal organs and hind limbs and that will serve as an opportunity for those regions to receive oxygen
There are other substances that will make its way down concentration gradient, but that’s for later
We have head blood heading up and down through major vessels (arteries) and get smaller and smaller until they reach those capillary beds
Ultimately drop off the oxygen that hey have to those areas that need it
Steps 9 and 10:
Not necessarily sequential steps here
9: superior vena cava (SVC)
10: inferior vena cava)
Both 9 and 10 bring oxygen depleted blood back to the right hand side of the heart via veins
Going to right atrium
Step 11: right atrium
Blood that is depleted in oxygen going to right atrium via veins called superior vena cava and inferior vena cava to start process again
While we’re putting this stepwise in terms of right and left hand side, the ventricles (both left and right) simultaneously contracting through this process
Now like pulmonary circuit first, systemic circuit after
Both happening very close together
One cohesive event

Question 16

Anterior structure of the heart

Answer 16

Sulcus or grooves
Coronary sulcus referred to as atrial ventricular one
Encircles the heart
the atrioventricular portion separates the right atrium from right ventricle
Anterior interventricular sulcus as well as posterior interventricular sulcus
these are going to extend down towards apex of the heart
These sulcus harbor the largest of the coronary blood vessels
Coronary blood vessels will supply the heart the blood that it needs to continue functioning
Auricle = little ear
Auricle for both the right atrium and left atrium
Serves to help increase the atrial volume
Superior vena cava:
Blood drains back into the right side of the heart from this with deoxygenated blood
Both superior and inferior vena cava serve as large vessels that will bring deoxygenated blood to the right hand side
Aeota:
Curve and from aortic arch
Several branching off
Diff vessels (arteries) that branch off and go towards different places in the body with oxygenated blood from pulmonary circuit

Question 17

The Mammalian Heart: A closer look- VALVES

Answer 17

Atrioventricular valves:
Separate the atriums from the ventricles
On the right hand side, tricuspid valve, left hand side, bicuspid valve
Tricuspid valve (btwn right atrium and right ventricle):
Three cusps
Bicuspid valve (btwn left atrium and left ventricle):
Two cusps
When it comes to the valve, we can see that there are these little connections that are referred to as chordae tendineae
Connect the valve cusps to the papillary muscle seen on the floor of the ventricle
Benefit on having this, is to prevent valves from flipping inside out when the ventricles contract
Want them to stay in their conformational state as we go through diff portions of the cardiac cycle
In addition to atrial ventricular, or AV valves, there are also semilunar valves
There is the pulmonary valve and the aortic valves
In total, there are 4 diff valves
2 associated with the relationship between the atrium and ventricle
The other two associated with movement out
Movement out into systemic circuit (aortic valve) or pulmonary circuit (pulmonary valve in pulmonary trunk)
Pulmonary valve controls the opening between the right ventricle into the pulmonary trunk (to go from deoxygenated blood to oxygenated blood)
Aortic valve controls the opening from the left ventricle into the aorta
Oxygenated blood to the arteries in aorta to go to systemic circuit (all around the body)
The valves don’t open or close through muscular effort, they open or close due to blood pressure which will change as blood contracts (sistilly) or contract which is diastole

Question 18

The Mammalian Heart: A closer look (Four Chambers)

Answer 18

When it comes to the chambers, there is two atrium
Atrium have thinner walls
Role in receiving blood that is going to drain from major vessels
Fossa ovalis
Indentation
That’s going to be seen in the interatrial septum
Septum is what will partition left and right side atrium from one another
Depression is indicative of where an opening used to be within the fetal heart which under normal conditions should close
Ventricles make up the most volume of the heart
Ton of room that’s there
Also have a septum shown as interventricular septum
There isn’t a specific term to show that there is a septum that separates atrium and separates ventricles
We expect that bc we have distinct oxygen content when we look in our diff chambers within the heart

Question 19

The Mammalian Heart: A closer look- THREE LAYERS OF HEART

Answer 19

The epicardium, Myocardium, endocardium, make up the three layers of the heart wall
Epicardium = superficial, outermost layer, infiltrated with fat
Middle layer = myocardium
Bulk of heart
Responsible for contractions
Endocardium- third layer, innermost layer
endothelial cells
Lines the heart chambers
Continuous with the endothelial linings that are seen within the blood vessels that leave and enter the heart as well

Question 20

The Mammalian Heart: Form and Function- Atrium versus Ventricles

Answer 20

Atrium = receiving
Ventricles = distributing blood to the lungs (right ventricle) or to the body (left ventricle)
-Ventricles are much larger than atriums

Question 21

The Mammalian Heart: Form and Function- Left and Right Ventricle

Answer 21

The left ventricle is way bigger than right ventricle

• the left is much thicker than the walls of the right ventricle
• cavity of left more circular, right more crescent shape and encloses left ventricle

Diff lies in where ventricles are sending blood to

• left ventricle much stronger is directing blood to the rest of body so it generates more pressure as it is a more powerful pump bc of the distance it needs to travel
• right ventricle, still responsible for pumping and building up pressure, but only heading towards the lungs, so the muscles aren’t as strong as it is short distance

Question 22

Phases of cardiac cycle: Ventricular Filling

Answer 22

Ventricular filling phase:
Time in which blood is going to go to the atrium down the ventricles
Ventricles are relaxed and referred to as diastolly
During this process, the pressure in the left ventricle and right ventricle are lower than left and right atria
Allows for the movement of blood down its pressure gradient
High pressure to low pressure
At this point, the atrioventricular valves (tricuspid valve for right and mitral/bicuspid valve for left) open, and thats whats essential for blood to flow in this direction
We see higher pressures within the pulmonary trunk and within the aerto, and as a result, the semilunar valves (pulmonary valve and aortic valve) are going to be in a closed state
During ventricular AV valves open, semilunar valves closed, and ventricles filling up with blood
Most of the filling that occurs within the ventricles occurs in a passive way, but small fraction will be forced in through atrial sistely
A time in which atria will purposevely contract, so force any residual blood that still remains within those chambers to ventricle
At the end of this process ,we will the end diastolic volume
Total amount of blood that will be found within the ventricles and we can see that within this cycle and measure in mL values

Question 23

What is cardiac cycle:

Answer 23

• mechanical physiology of the heart

- Mechanism in which blood fills within chambers and eventually gets pumped out

Question 24

Cardiac Cycle- Ventricular filling phase:

Answer 24

Ventricular filling phase:
Time in which blood is going to go from the atrium down the ventricles
Ventricles are relaxed and referred to as distally
During this process, the pressure in the left ventricle and right ventricle are lower than left and right atria
Allows for the movement of blood down its pressure gradient
High pressure to low pressure
At this point, the atrioventricular valves (tricuspid valve for right and mitral/bicuspid valve for left) open, and thats whats essential for blood to flow in this direction
We see higher pressures within the pulmonary trunk and within the aerto, and as a result, the semilunar valves (pulmonary valve and aortic valve) are going to be in a closed state
During ventricular AV valves open, semilunar valves closed, and ventricles filling up with blood
Most of the filling that occurs within the ventricles occurs in a passive way, but small fraction will be forced in through atrial sistely
A time in which atria will purposevely contract, so force any residual blood that still remains within those chambers to ventricle
At the end of this process ,we will the end diastolic volume
Total amount of blood that will be found within the ventricles and we can see that within this cycle and measure in mL values

Question 25

Cardiac Cycle: Isovolumetric Contraction

Answer 25

Isovolumetric contraction
Beginning of ventricular contraction
This is one of the shortest phases of cardiac cycle
During this phase, the pressure of the ventricle goes up, and it goes up to such an extent that the pressure exceeds that that of atrium, so atravastriuclar valves are going to close
When AV valves close, it thought to cause the S1 heart sound, which is thought to be due to blood surging against closed atrioventricular valves
The “lub” sound
Increase in ventricular pressure not high enough to open up semilunar valves (to aortic valve for left and pulmonary valve for right)
Which means pressure is not higher than what is seen in pulmonary trunk in the aorta at his time
All of the valves are closed
The volume that enter the ventricles during the initial phase of ventricular filling hasn’t changed
Starting to force blood in particular direction bc ventricles are contracting but the ventricular volume isn’t changing bc it has nowhere to go bc valves are all closed
Atrodiastally will begin
During ventricular filling, was a moment where atrosiling occurred to force out blood that still remained from atrium to ventricle
So atrium will now be in relaxed state
Isovolumetric contraction phase:
Ventricular Cisitilly
All valves in closed
Atrodiastally

Question 26

Cardiac Cycle: Ventricular Ejection

Answer 26

Ventricular ejection
Pressure within ventricles are high enough that semilunar valves are able to open and will end isovolumetric phase
During ventricular ejection, shrill have contraction of ventricles but now pressure is enough that semilunar valves are able to open up and blood can now go from left ventricle to aorta through aortic valve and from right ventricle to pulmonary trunk through pulmonary valve
As phase continues, pressure within pulmonary trunk and aorta (both arteries) is going to approach that of ventricles
Start to become comparable to one another
Force of blood decreases consiblely
At first there’s rapid ejection, followed by reduced ejection
Like carbonated beverage and shake it up, how it would respond initially versus after some time
During process, we’re going to see that ventricles will expell some of their blood, but not all of it

Question 27

Cardiac Cycle: Isovolumetric relaxation

Answer 27

Final phase = isovolumetric relaxation phase
Ventricular diastasis
Ventricles are relaxed
Pressure is going to decline in ventricles
That decline in pressure is going to change the pressure between ventricular pressure and semilunar pressure (
As a result, semilunar valves going to close
As semilunar valves close, going to have second heart sound, or S2 sound
When it comes this phase, pressure in ventricles still higher than atrium
Atrioventricular valves also going to be closed
All of the valves of closed, blood is not being ejected nor entering, and volume will remain constant for a short amount of time
There is a change is seen within ventricular pressure during the process of ejection, that change of pressure during ventricular sistilly impacts the amount of blood that is capable of being ejected from ventricle
So entire volume does NOT become ejected during that portion
Residual blood in both ventricles
That is referred to as end-systolic volume (ESV)

Question 28

Review of Phases of Cardiac Cycle:

Answer 28

1. Ventricular Filling
   - blood will go from atrium to ventricles
   - ventricles = relaxed and are referred to as distally
   - pressure in ventricle lower than atrium, which is why blood goes down as it goes down the pressure gradient
   - atrioventricular valves open
   - semilunar valves closed as there is higher pressure there
   - post blood filled into ventricles is passive, small amount forced in via atrial sistally as antria contact to force any residual blood to ventricle
   - end of this process, we have end diastolic volume = total volume found within ventricles we can see within this cycle and measure in mL value
2. Isovolumetric Contraction
   - beginning ventricular contraction
   - shortest phase
   - pressure of ventricle goes up and exceeds atrium pressure, os atrioventricular valves close; which causes S1 heart sound which is though of as blood surging against closed atrioventricular valves; called lub sound
   - semilunar valves closed
   - all valves are closed so volume is the same as ventricular filling phase
   - atrium will be relaxed
3. Ventricular Ejection: pressure within ventricles high so semilunar valves open and with the contractions from isovolumetric contractions, and now semilunar valves open, blood goes to pulmonary valve (blood from right ventricle) and to aorta valve (from left ventricle) to circulate
   - pulmonary trunk and aorta starting to build pressure
   - force of blood decreases over time as there is fast ejection at first
   - ventricles will not expel all their blood, some will be left over
4. Isovolumetric Relaxation
   - ventricular diastases = ventricles are relaxed as pressure declines and semilunar valves going to close so now we have all valves closed as atrioventricular valves already closed is ventricular ejection
   - as semilunar valves close, going to have second heart sound, S2 or dub
   - blood is not being ejected or entering and volume will remain constant for short amount of time
   - residual blood from ventricular ejection, which is referred to as end systolic volume

Question 29

Graph showing relationship btwn pressure and volumetric volume in ventricle in cardiac cycle

Answer 29

Ventricular filling:
-pressure of artium higher than ventricle; so atrioventricular valve is open and blood flows from high pressure gradient (atrium) to low pressure (ventricle)
-ventricular volume is high
-at the end of ventricular filling, (also called diastolly), and so the total amount in ventricle is the highest amount in cycle, called the EDV, end diastolic volume
Isovolumetric Contraction:
-pressure builds up in ventricle and becomes higher than atrium, so atrioventricular valves close, but lower pressure than aorta (as we’re on the left we’re talking about aorta), so semilunar valve also closed
-at this time, ventricular volume the same as the end of ventricular filling
Ventricular Ejection:
-pressure of ventricle higher than aorta so semilunar valve opens and blood goes from high pressure (ventricle) to low pressure (aorta)
-at the end of this, ventricle volume is the lowest as systilly (ejection) is completed and is called end systolic volume
-reminder that not all blood from ventricle will be ejected, some will stay in
Isovolumetric relaxation:
-ventricles relax and pressure is less than aorta, so semilunar valves close
-but ventricle pressure is still higher than atrium, so atrioventricular valves are closed as well
-all valves are closed and ventricular volume is the same as at the end of ventricular ejection, at the ESV point, end systolic volume

Question 30

Cardiac Output

Answer 30

Cardiac cycle being an opportunity to hear those SI (EDV) and S2 (ESV) sounds, cardiac cycle constitute a beat
Our heart is going to go 60-80 cardiac cycles, or 60-80 beats per minute, that’s our heart rate
When it comes to stroke volume, that is what is seen when we are looking at the difference between our end diastolic volume (at the end of ventricular filling) and our systolic volume (at the end of ventricular ejection)
Bc that’s the amount ejected from each ventricle
That’s our stroke volume
Can take info of heart rate (how many cardiac cycles) and stroke volume (how much blood being ejected from each ventricle)
Use it to determine what is called cardiac output
Cardiac output: amount of blood that is pumped into both the pulmonary and systemic circuit within a min
Looking in units of mL/min
Cardiac output can fluctuate bc there is diff factors that influence heart rate and stroke volume, won’t get into those details
In order to determine your cardiac output, we are going to find the product of the heart rate (how many cardiac cycles in a min) and stroke volume (how much blood ejected in each cardiac cycle) to get cardiac output
Cardiac output changes based on body’s blood flow demands and can be influenced by these two factors fluctuating in some way
The mechanisms in which they change not important but knowing that heart rate and stroke volume impact cardiac output bc the product of these two values results in cardiac output so anything that’s going to increase or decrease heart rate or stroke volume, is going to have a direct impact on cardiac output

Question 31

Maintaining the Heart Rhythmic Beat

Answer 31

Thought out mechanic physiology of the heart
Now thinking about electrical
Heart beat is coordinated by conduction system
Going to be signals throughout the heart that allow for those events to take place
We have a pacemaker cell and a conduction pathway through myocardium (one of those layers of heart wall)
Some cardiac muscles are autorhythmic so they don’t need any connection or communication with nervous system in order to continue the process, they just isolate through that cycle over and over again
We will go through the process of maintaining heartbeat
Book focuses on the sinoatrial node (SA node) as being the pacemaker without reference to the fact that other types of autorhythmic cells we find here can also be considered pacemaker, they’re just not the pacemaker cell
1. Signals (yellow), signals coming from sinoatrial node (SA node)
sinoatrial node (SA node) is going to be composed of modified cardio sites, which are cells that are found within right atrium
They are going to be near superior vena cava (vein where oxygen depleted blood comes back from after systemic circulation)
Pacemaker cells will initiate the heartbeat and also determine the heart rate
Signals coming from sinoatrial node (SA node) are going to spread through atriomycardial
All of it displayed in yellow
Step 2: signals are going to get delayed at AV node and delay going to occur at the atrioventricular node
Going to ensure that atria has a chance to fully respond before progressing forward bc signal is going to allow for atrial contraction to take place (for ventricular filling?)
The AV node is located at lower end of the interatrial septum near the right atrioventricular valve
This node is going to provide a gateway to the ventricles in the lower portion of the heart
Step 3: movement away from the AV node and to the bundle branches
Bundle branches are going to fork into left and right bundle branches as they work their way down interventricular septum towards the heart apex
Step 4: signals spread throughout ventricles
That movement towards heart apex bc from here we go to the purkinje fibers, which will be found on lower part of bundle branches, they’re going to turn and spread their way upwards throughout the ventricular cardium
Helps to distribute electrical excitation to the cells of the ventricles
When it comes to network seen here, more elaborate on left hand side bc of the more complex left ventricle role
This movement starting from the apex and working our way upwards and then thinking about the muscles of the heart is organized is like taking tube of toothpaste, ensuring you start on the bottom of that toothpaste tube nad pushing it to the top to get the most efficient movement of blood out of ventricles
Below these steps that are responsible to maintaining heartbeat (how many beats per cycles), we have an electrocardiogram display
We can correlate these diff events with diff deflection of movements and what the mean on a more superficial level on the next slide
if so the pacemaker comes first and is auto-rhythmic in nature so there will be natural changes in the voltage seen across the membrane in these cell types - those changes will induce a contraction pathway that yields mechanical change

Question 32

Blood Pressure and Gravity

Answer 32

ECG graphic representation of electrical activity in the heart, and its taking place during the cardiac cycle
Impulses from the heart spread to other body tissues and fluids that are found in the surface of our skin and as a result of that movement we can measure these events through electrode
ECG can pick up certain waves
Not gonna go through the segments, go through the waves bc anything more detailed is not relevant
Look at P, QRS complex and T wave
When thinking about these diff waves, we sue terms depolarization and repolarization
Changes in electrical distribution within the heart
Depolarization: discussion or our neuron chapter
Change the electrical distribution in such a way that we will be able to proceed with systolly (contraction)
Repolarization: head back into resting state and associate that with diastolly (relaxation)
Link these specific deflection waves with fluctuation or changed that we would associate with nervous system or changes in ion concentration
P wave= atrial depolarization
Atria are depolarizing
Happens from the signal node (SA) spreads throughout the atrium and astrosystilly (atrium contracts and blood goes into ventricle ) begins a little after the P wave begins
QRS complex = large one
Associated with ventricular depolarization
Its higher than atrial depolarization bc of the thickness of the ventricles and the increased force in which they contract
Blood comes out of ventricle
Going to produce signal when the signal from the AV node spreads through the ventricular michocharium
Michochardium has the biggest muscle mass, so going to generate the greatest electrical current
Also atrial repolarization (relaxation) happening at this point but bc of how significant QRS complex is during ventricular depolarization, it’s going to mask atrial repolarization
Even tho its not specifically indicated here, there is both atrial and ventricular depolarization as well as repolarization
T wave:
Ventricle will relax
With ECG, abnormalities or deviations from this expected trend means problems with the conduction system, let us know that something wrong with the sinoatrial node (SA), atrioventricular node, or the BIrgingue fiber system or issues with cardiac muscle

Question 33

Blood Vessel Structure and Function

Answer 33

Blood vessels have basic patterns of organization
Their tubular and they have aluminum thats surrounded by tissue layers
When it comes arteries and veins, they have very similar composition but they’ll just have varying distribution of those components
Innermost layer = endothelium
Continuous with the endocardium
Endothelial cells provide surface for blood to flow through
Smooth surface so reduce friction and tumberlance with can negatively impact blood flow
Endothelial cells can also produce chemicals
Smooth muscle:
Difference between the amount of smooth muscle in artery side (more smooth muscle) than in vein
Helps to control the diameter of blood vessels can therefore control the amount that flow to organs
A little bit more of a regulatory role in artery side vs vein bc vein is reservoir with collects blood so its more passive
Outermost layer:
Composed of connective tissue
Connective tissue to support blood vessels and prevents it from overstretching
Much more likely overstretching will take place in artery bc of the amount of pressure it needs to deal with as opposed to veins
So there’s more connective tissue in artery
Capillaries:
Aren’t the same
Don’t see smooth muscle, just see endothelium and basal lamina
Capillaries consist of endothelial cells joined by tight junctions and organized in a way that only permit RBC in a signal file fashion, one at a time
Beneficial bc capillaries, exchange takes place so we want to make sure that each of these erythrocytes is able to pick up and drop off what they need
Veins will have valves
While we don’t see that reflected within the arteries and that is due to then need for blood to not go backwards in the vena circuit
That is due to strong opposition in certain opposition in the veins, like in the legs, due to gravity,
Would want to bring blood down but we want to put blood back into heart so we have valves for it to not go backwards
Think about relationship between form and function nand how these vessels are similar or different and how they help to support the role in cardiovascular system

Question 34

Hemodynamics

Answer 34

The way that blood, velocity, area and pressure changes as we move through diff vessels within systemic circulation
Vessels of circulation are going to vary with respect to their total cross sectional area
Top panel
Changes can impact velocity of blood flow through them
Velocity is measured in cm/sec
Top and middle panel: velocity is inversely related to cross sectional area
When we have a high velocity, have a low cross sectional area
Velocity of blood flow change as blood travels through systemic circulation
Its fastest within the aorta, which is proximal to heart as well as larger arteries
Slowest in the capillaries
Capillaries:
Total cross sectional area significantly increased
That’s due to the bunch of branching into these smaller capillary beds/networks
Even tho the lumen of the capillaries is smaller than aerities, tis the combined cross sectional area of the capillaries (l x w) than the arteries, which is way bigger than aeries
Increased total cross section of capillaries, increases the volume of blood that the capillary vessels can collectively hold, so slow down the velocity bc bloods gonna be distributed more widely
When it comes to speed, cross sectional area is going to come back down as we go from capillaries to veins
Blood converging into these vessels (veins), which allows for velocity to pick back up again
Velocity is not gonna reach same heights as aorta bc of the distance of vessels such as veins and superior and inferior venae cavae from the initial kinetic energy that;’s imparted on blood after it leaves left ventricle
Velicty is very high at aorta due to proximity to the left ventricle (blood coming in very fast and small cross sectional area)
Comes down bc total cross sectional of capillaries goes up so tons of space for blood to distribute into (low velocity, high combined surface area), but then blood converges to fewer and fewer vessels (veins after going to systemic circuit through capillary beds), which brings the velocity back up again and lower surface area
For blood pressure, what we see is a puslatel state
Goes down and up in regular fashion
Peak is generated by ventricular contraction, systolic pressure (contraction)
During diastolly, aortic valve closes which prevents blood from flowing back into the heart and the walls of the the aorta will recoil, and there’s still enough pressure to keep blood flowing
Closing of aortic valve, pressure response that is lower during ventricular contraction but still enough for blood to continue flowing
Small drop in aortic pressure, which will be diastolic pressure
Bc the aortic pressure is fluctuating here, the mean arterial pressure, or the mean pressure is what we utilize our quantitative value for propelling blood through tissue
Pressure is oscillating bc of diastolic pressure and systolic pressure

Question 35

Regulation of Blood Pressure:

Answer 35

In thinking about blood pressure, we know that its pulsiltial
It changes as we transition through diff vessels
Also diff mechanisms that can impact blood pressure
That can help to achieve homeostasis
There are multiple ways in which blood pressure can be regulated by the means in which we can achieve that is through changing diameter of arterials
vasoconstriction and vasodilation
Vasoconstriction: contraction of smooth muscle, and that contraction if smooth muscle will change size of lumen, there’s going to be an increase in blood pressure
This makes sense as when ventricles contract (meaning the smooth muscle of ventricles contract), it causes an increase in blood pressure
Vasodilation: relaxation of smooth muscles within arterioles, there is change in lumen diameter and that change in this senior will cause blood pressure to fall

Question 36

Smooth muscle relaxation pathway:

Answer 36

Step 1: Acetylcholine, which is our ligand that will bind to receptor found on endothelial cells of blood vessels
Ligand serves as primary messenger, and as a result of ligand event, going to activate receptor, result in production of IP3
IP3- example of a second messenger
IP3 is going to be a ligand that can bind to a ligand gated channel that is seen within the cell
Step 2: there is an IP3 gated channel (not the receptor as that is already activated via acetylcholine, the ligand) , IP3 binding to that channel allows for Ca2+ leave the lumen of the endoplasmic reticulum, down their concentration gradient out into the surrounding fluid, into the cytosol
Sum up of first two step: we have acetylcholine binds to its receptor
The receptor binding leads to IP3 production which is second messenger
Ip3 will bind to a channel that has a ligand binding spot for IP3,
As a result, Ca2+, which is build up in the lumen of endoplasmic reticulum will diffuse down its concentration gradient into the cytosol
There are Calcium ATPase’s that help to ensure that Calcium ion concentrations are very low in the cytosol, so they are more sensitive to changes to calcium ion concentrations
Step 3: the presence of the Ca2+ ions in the cytosol results in the activation of an enzyme
That enzyme is a nitric oxide synthase
That nitric oxide synthase is going to lead to production of nitric oxide gas
Utilizing arginine in the cytosol to facilitate that process
Through this transduction pathway, we’re able to generate nitric oxide
Step 4: Nitric oxide is pretty unstable and relatively reacts with other molecules within its vicinity
Nitric oxide that is generated is capable of diffusion out of endothelial cells and towards nearby smooth muscle cells
Proximity is important here
When we take a look of the impact that Nitric oxide has, it will go to smooth muscle cells and help stimulate cyclic GMP synthesis (cGMP)
Step 5: cGMP present, that’s going to trigger a response that causes smooth muscle cells to relax
When we have muscle relaxation that is going to increase blood flow
Ex: natural glycerin drug can be used by chest pain bc of insufficient blood flow to the heart \
That helps release NO and increase blood flow
Ex: cydelinfil; inhibit phosphodiesterase activity
Phosphodiesterase are enzymes that help to convert cyclic nucleotide back to non cyclic version
So phosphodiesterase inhibitor is going to prevent cGMP from being converted into GMP, which will increase concentrations of cGMP, and promote muscle relaxation

Question 37

Blood Pressure and Gravity

Answer 37

Relationship of blood pressure and gravity
Process of fainting is a result of there not being enough blood flow to top of the body
Animal long neck, inspect for some adaptation to ensure enough blood getting to head
Giraffe has high systolic pressure to pump blood across that distance against the force of gravity towards head
When it comes to pressure in general, blood pressure tapers off as we get to veins
Really difficult on its own for blood there to return to heart for subsequent circulation
As a result there are diff mechanisms that help to assist with venous return
Ex shown here: muscular pump, based on the movement of skeletal muscles
Skeletal muscle here is surrounding veins andas skeletal muscle surrounding veins contract and relax, going to squeeze blood towards the heart
As blood goes back a particular valve, valve will close off and prevent any backwards flow to make sure we make our way to top of the body
Professions where they stand still will have issues with blood pooling bc they are not going to have enough skeletal muscle contraction to ensure blood returns efficiently
So i think low blood pressure means constant relaxation and blood flow away from heart, and not enough going back to heart, so hard to circulate everywhere, so less blood in head, which can lead to fainting

Question 38

Capillary Function

Answer 38

Capillary function
Capillaries form networks called capillary beds
Flow of blood to arterioles (arteries) to venule (veins) is called microcirculation
When it comes to the amount of blood that is found within bodies, not enough for it to be everywhere in our body at the same time
At rest, there’s boly a small fraction of the capillary beds that are open and allowing for movement of blood to occur all through capillary network
When we have capillaries provides opportunity for exchange of gases, nutrients, waste within the surrounding area
In order to regulate diff areas of the bodies, deciding where we will be able to diverge some of the blood flow to diff capillary, we have these capillary sphincters
capillary sphincters are on arterial side, act as valves that regulate blood flow into the capillary
Can be controlled by chemical conditions within localized areas
Can regulate, when thinking about fight or flight, towards skeletal muscle and away from digestive system in order to help with process of running away
In the relaxed state of capillary sphincters, there is movement of blood all throughout
Heads through main thoroughfare channel
This is what is directly connecting arteriole and venule and its also traveling through true capillaries
We see blood flow everywhere
Precapillary sphincters will be open
If precapillary sphincters contricited, still have blood flow, but we’re only going to have blood straight from arteriole, through the thoroughfare channel into the venule without passing through the true capillaries

Question 39

Fluid exchange btwn capillaries and ISF

Answer 39

cardiovascular system = closed system
Bc the vessels are connected w/ one another, nothing is open ended but based on how our vessels are organized, water and solutes within our blood can exit out through the walls of the capillaries and that will exit out into the interstitial fluid (ISF)
Most of the fluid leaves the capillaries at the martial end of capillary rather than the venous end of capillary due to the amount of pressure seen at article end
Most pressure builds up in artiel means that more fluid will be lost
The size of arrows shows the amount of pressure, and thus the amount of fluid that is moving out of the capillaries
When it comes out fluid lost, we don’t want to lose this because we need to utilize these fluids to maintain pressure and essential blood flow
So we want to return that fluid and that fluid can be returned through osmosis, certain level of osmotic pressure that’s applied to capillaries
Reason why that can be accomplished is bc within the vessels, there exits plasma proteins
Proteins are found within our blood and the size of them makes it impermissible for it to make its way out of capillary
Can’t really escape the pores found within this blood vessel
What that means there’s going to be an increase of concentration of these plasma proteins in the blood plasma that is going to be significantly higher than what is seen in interstitial fluid
Diff in protein concentration causes water to want to enter the capillaries
The idea of osmosis and the idea to generate equal distribution of concentration on either side
Rather than move the solute, which in the scenario is the protein, what we’re doing is utilizing water to try and create distribution on either end
The body is trying to dilute the proteins in capillaries in order to each equilibrium to a certain extent
The difference causes water to move in (blue arrow via osmotic pressure)
Will move from interstitial space into the vessel
When you compare arrows here, arrows constituent with respect to length
Regardless of which end of capillary we’re at, the plasma protein concentration is constituent, so the osmotic pressure is consistent
Where we’ll see a difference is the net fluid movement cell
The difference between the net fluid movement out is based on the fact that blood pressure is declining as we move from one end to another
Osmotic pressure is present, under normal conditions, when those plasma proteins are there
When it comes to abnormal situations, it’s entirely possible that capillary blood pressure can be too much and there can be too much fluid that enters into the interstitial fluid and will end up accumulation
This can cause edema, which is swelling of tissues
Commonly seen in pregnancy due to the increase of blood volume and the compression veins due to changes in uterus size and results in increased blood pressure in lower limbs
Can be temporary edema or depending on severity or issues that occur within certain systems within our body, it can be long lasting and needs to be clinically addressed

Question 40

Fluid Return by the Lymphatic System

Answer 40

There’s always going to be more fluid filtering out hat needs to be returned
When we take a look at net fluid movement, when looking at arrows, those arrows always a little bit longer, even at far end of capillary, at venous end, a little bit more than that of osmotic pressure
So movement is going to favor fluid loss
When it comes to this fluid loss, we do have mechanism of return, which will occur via lymphatic system, shown in green
Lymphatic system is composed of a bunch of vessels, there are capillaries, other lymphatic vessels, lymph nodes, lymph organs
When it comes to lymphatic system and the vessels, they are really permeable
Important as it will allow for fluid found within tissue to drain into them
Trying to pick up that residual fluid loss that occurs bc blood pressure is going to exceed the osmotic pressure in capillary beds with the transfer of fluids
As a result of that there will always some fluid lose as it moves through capillaries
Lymphatic system job is to help return lost fluid to circulation
The movement of that fluid, once it enters a lymphatic vessel, its referred to as lymph and lymph will move through vessels through one way valves until the lymph essentially enters two major vessels which drain into subclavian veins
Subclavian veins found under collarbone
Lymphatic system, in contrast to cardiovascular system lacks a muscular pump, so movement on lymph depends on skeletal muscle
So squeezing against the vessels will help to drive the lymph to where it needs to go

Question 41

intro to module 4: blood components function in exchange, transport, and defense: what is blood?

Answer 41

Blood components function in exchange, transport, and defense
The role that blood plays a little bit beyond the obvious
When we say blood we’re thinking about erythrocytes, when blood is a type of specialized connective tissue that’s comprised on many things
Emphasis on closed circulatory systems, bc that’s what we have, but when it comes to open circulations that fluid is continuous with the fluid that surrounds all the body cells
Hemolymph in open circulation bc of that continuous nature, whereas for closed circulatory system, they’re confined to vessels which is where we would use the term blood

Question 42

Blood composition and function: Formed elements

erythrocytes in bottom layer and leukocytes and platelets in buffy coat

Answer 42

Take a vial of blood and centrifuge it, we would be able to separate the diff components based on their relative densities
That’s what we have here
The most dense component of our blood are the formed elements
More specifically that of the erythrocytes
We can find erythrocytes at bottom portion
They constitute a relative significant fraction of the formed elements compared to others
5-6 million erythrocytes compared of ¼ of a million of platelets and 5,000-10,000 leukocytes
Erythrocytes or red blood cells, make up a really significant portion of the formed elements
Or the cellular elements
Term that we can use for the erythrocytes is the hematocrit
Hematocrit is the packed cell volume, % of the whole blood volume that is composed of RBC/erythrocytes
When it comes to this value, it can fall within particular range, hematocrit value has been shown to be higher slightly in men compared to women
One possibility is the role than androgens will play
Androgens are higher in men that women and androgens stimulate erythrocytes production
Another psychosocial component can be reproductive age of a women, based on that, there will periodic blood loss due to menstrual cycle
When it comes to hematocrit, has an inverse relationship to body fat, and the average body fat is higher in woman that in men
Three diff ways in which we would see a hematocrit lower in women that to men
Erythrocytes: the goal is to transport gases
There’s movement of oxygen, movement of CO2
The amount of erythrocytes that we have bc we have a ton of theme bc we are prioritizing that movement and diffusion of gases throughout the diff regions in our body

If we focus on our vile, what we’ll see if that the bottom portion of our tube contains erythrocytes, but then there’s this small layer in white, this is referred to as the buffy coat
Buffy Coat
Locate both leukocytes and platelets
Leukocytes/WBC
Have a known role in defense and immunity
When looking at the number per microliter of blood, they fall within a particular range of 5,000 to 10,000 with numbers increasing depending on the needs of the individual
Connection back to the idea of clonal selection and amplification during an immune response
Leukocytes have glandular cities
If we were to peak into the cell, would find glandular/punctate sites and there are agradular sites, those that are lacking gandules
When it comes to neutrophils:
These are granular sites and they are the most abundant types of Leukocytes that we have
Aggressive in their attack of bacteria
Neutrophilia is going to occur in response to bacterial infection
Assess a response to bacterial infection due to increase in neutrophils within the body
Eosinophils (glandular sites):
Cna secrete chemicals, those chemicals can weaken or destroy large pathogens
Hookworms, tapeworms, that are too large to go through process of phagocytosis effectively
Basophils: (glandular sites)
Rarest of formed elements
Secrete vasodilates which will change the diameter of the blood vessels, they’ll increase it through dilation
They’ll also be anticoagulants, there can be release of other chemicals that can attract eosinophils and neutrophils to sites of infection
When thinking about agranular sites, there are lymphocytes:
Lymphocytes: B cells, T cells, natural killer cells
Very abundant after neutrophils
Monocytes:
Can give rise to macrophages
Macrophages are professional eaters, go through phagocytosis
Ex of antigen presenting cells
To recap: granular sites are neutrophils, eosinophils, and basophils
Angrnadular sites are lymphocytes and monocytes (macrophages)
When it comes to this idea of granules, looks like monocytes has graduales, they are indeed agrandules (lacking granules/punctures)
When we think about lymphocytes, think about overall role as it relates to defense and immunity
Second part of buffy coat: platelets
Platelets not actually cells when compared to erythrocytes and Leukocytes
Fragments of cells called megakaryocytes (really big cells)
In the process platelet formation, those megakaryocytes will stick cytoplasmic extensions out into openings, and those openings will be found within blood vessels
The force or movement of blood flow will sheer off those extensions
Sheared off extensions constitute platelets
Platelet count vary greatly, due to varying physiological conditions, play a role within blood clotting
Gone through formed elements/cellular elements:
Bottom part of formed elements
erythrocytes/RBC
Buffy coat
Leukocytes (WBC)
Platelets
These are in middle white sliver

Question 43

Blood composition and function: plasma (top part)

Answer 43

Shift into plasma (top part)
Blood is a type of connective tissue
Connective tissue requires some means of support, that support is provided through a matrix
Plasma serves as a liquid matrix that supports the contents of blood
Makes up the majority of blood volume
Plasma has water, ions, plasma proteins, and additional nutrients that move throughout the medium
The bulk of plasma is water
That is going to serve as solvent to dissolve solute that are found within the volume of blood
Ions:
Role they play with osmotic balance
Plasma Proteins:
Albumin = plasma protein
Content of plasma and role they play with respect to osmotic balance
Won’t really go into immunoglobulins (antibodies) already been discussed
Now that previous discussions, antibodies can play a role in defense through neutralization and interaction that can increase optimization
Defense and immunity
Apolipoproteins:
Which are responsible for lipid transport
Fibrinogen:
Associated with clotting
There are also substances that gets transported by the blood and as we expect, O2 and CO2 will move through there bc we want to bring them to diff locations within the body, waste products, and there are hormones
Hormones are moved in endocrine system long distance, and gets accomplished through the blood and is moving specifically within the plasma
If something deviates from hemostasis, if values go up or down, what can that tell us of what body is trying to do or what it is incapable of doing

Question 44

Erythrocyte structure and composition

Answer 44

Erythrocytes
When thinking about form and function, there are a few things to consider
One is that Erythrocytes are pretty small in size
7.5 micrometers by. 2.5 micrometers
Small size in shape is thought to help optimize or enhance the surface area to volume ratio
Efficiency of movement of solutes from one location to next and if we start to change volume, what impact would that have of efficiency of moving things, what limitations are there to surface area to volume ratio
Another thing is by the time we’re thinking about an Erythrocytes, this is its mature form, and by the time its matured, it has essentially ejected all of its content
Composed aside from water with a ton of hemoglobin molecules
Composed of hemoglobin and enzymes and removing all of the other content and filling this shape with a ton of hemoglobin and enzymes help to optimize the role that Erythrocytes play in the transport of respiratory gases (O2 and CO2)
With our hemoglobin molecules, we can have oxygen bound and carbon dioxide transport
If we eject everything else, we can prioritize the space that we need to serve the primary role of oxygen and CO2 exchange
Since these Erythrocytes are void of organelles, they are anucleate, which means they are lacking nucleus and no organelles
Lack mitochondria, considered powerhouses, and integral to ATP production
That can be accomplished through oxidative phosphorylation
In this scenario, have Erythrocytes that lacks mitochondria which means that ATP can occur, but the mechanism by which it occurs is different
Anaerobic means to produce ATP, process of fermentation
That process allows for production of ATP, not as much as aerobic conditions
Mature Erythrocytes/RBC utilizes anaerobic fermentation is good thing in this case
Its highly beneficial to utilize anaerobic fermentation bc we don’t want the v to utilize the oxygen that it should be transporting bc its meant to bring it somewhere else
In harnessing anaerobic fermentation, ensuring that they’re not using oxygen they are carrying
Job is to transport, not use transport
Only human cells that will carry on anaerobic fermentation indefinitely
Erythrocytes also have structural proteins, and they are Cytoskeletal
There is spectrin and there is actin found in Erythrocytes
Found on the cytoplasmic face of the plasma membrane
Cytoskeletal proteins help to maintain the biconcave shape
How it dips in in the middle
Having biconcave shape and cytoskeletal proteins is beneficial bc RBC are deformable

Question 45

Sickle Cell Disease

Answer 45

Sickle cell disease:
Example of a erythrocyte based disorder
Overview: sickle cell disease is a result of a point mutation, so a single change within a nucleotide impacts the DNA, which impacts the mRNA, which impacts the codon in such a way that the amino acid that results will shift
The property of that amino acid goes from being polar to non polar
As a result of that point mutation and amino acid change, the overall organization of the erythrocyte is affected
When we think about this defect, it is a defect in hemoglobin protein
When it comes to an erythrocyte, its essentially just a sac hemoglobin
Defected hemoglobin = change of the shape of the erythrocyte so that it is a sickle shape rather than the canonical biconcave shape of a normal erythrocyte
This is hereditary
Found in higher amount in african and mediterranean descent
Mutated hemoglobin, we focus initially on its position with an aqueous environment
Now we consider the mutated hemoglobin behavior in oxygen deficient environments
Mutated hemoglobin does not bind to oxygen well
So in places where O2 concentrations are low, hemoglobin becomes deoxygenated
Hemoglobin has a tendency to polymerize and forms a gel
This gel makes the erythrocytes elongated and point at the ends
Sickle erythrocytes are sticky and have a tendency to aggultatene
Agglutination is clumping together
Agglutination is very detrimental to our bodies bc agglutination can block small blood vessels and that can lead to intense pain in individuals, oxygen starved tissues, and blocking circulation impacts effective blood flow
If we don’t have blood flow to areas we need, it can result in kidney failure, heart failure, strokes, joint pain, paralysis
There is hemolysis which will destroy these cells themselves and in an effort to do that, anemi results
Anemia is a diminished hematocrit value (low amount of RBC)
With that decrease concentration of erythrocytes, and hypoxic conditions (low oxygen) that’s going to stimulate sickling
The process of entering areas where oxygen concentrations are low induces the polymerization
Decreased concentrations of erythrocytes due to hemolysis bc we’re trying to get rid of abnormal erythrocytes
Going to result in hypoxic bc we now we have less erythrocytes that are able to carry our dissolved gases
Stimulate process even more
In an attempt to fix the issue, body makes it worse
If there is chronic hypoxic conditions, that can cause fatigue
Can’t receive oxygen to tissue that need it
Can impact mental development and deterioration of heart and other organs
In order to counteract hypoxia, there will be hematopoietic tissues that will activate
But the level of activation that is seen within those tissues actually causes bones to become enlarged and sometimes misshape
Sickle cell disease = harmful and ex of pleiotropy
Pleiotropy: multiple phenotypic events that arise from a single gene
In places where the parasite that causes malaria is found, these sickle like shapes are useful bc the sickle cell is detrimental to the parasite that would feed on it
The advantage to this is conferred to the heterozygous individual
Pretty resistant to the disease that causes that parasite, which is malaria
The gene persists within a particular population
When thinking about sickle cell disease, think about the idea of changes within a polypeptide, and how that impacts protein behavior, and layer that on with circulating through various blood vessels and agglutination, and how can impact effective blood flow, and how ineffective blood flow means we have reduced capacity to exchange gases and that leads to hemolysis come in and kill those sickle cells, but it makes it worse as it results in anemia (lower amounts of RBC’s) which leads to hypoxia (low oxygen levels), and hypoxia triggers polymerization, and more sickle cells are made

Question 46

Stem Cells and the Replacement of Cellular Elements

Answer 46

We lose blood continuity through bleeding, blood cells reaching the end of life span, through using up components in plasma, receiving components through the process of excretion
Based on these events, oneworld expect there to be a need for continual replacement of these cell types in order or events that blood helps to support to continue
The process of producing additional formed elements is the process of hematopoiesis
Formed elements of blood trace their origins back to hematopoietic stem cells (HSC’s)
HSC located in bone marrow and are found in high mounts in ribs, vertebrae, pelvic, sternum
HSC’s are multipotent as these cells are destined to give rise to multi mature cell types downstream
HSC multipotent, hematologist do not use this term
They will use the term pluripotent, but stem cell biologist utilize multipotent and we will use that for hematopoietic stem cells
In thinking about stem cells, on capability they have is the ability for self renewal
Want HSC to be able to give rise to all of these downstream elements
HSC there are two lineages they can give rise to:
Myeloid stem cell lineage
Progenitor cells: a little more specialized
Called colony forming units
Each type of colony forming unit (have three in myeloid stem cell) are desitiend to make some type of fiend element downstream

Lymphoid stem cell lineage
Hematopoiesis process, think about the formation of formed elements
Megakaryocyte will give rise to platelets
Leukocytes discussed
And lymphocytes in lymphoid stem cell lineage
Blood can obtain water from absorption within digestive tract, acquisition of nutrients and electrolytes, and gamma globulin can come from connective tissue plasma
Proteins found within plasma can be derived from liver
In thinking about this slide, some of the info was already mentioned in immune system as well as the stem cell content,
Providing a general overview of HSC and connecting the necessity of these stem cell types to the production of the components of blood

Question 47

Hemostasis

Answer 47

The natural process of stopping the flow of blood
There diff hemostatic mechanism
One is forming a platelet plug
Another is formation of fibrin clot
One mechanism missing, which is a vascular spasm, most immediate response to blood loss
Constriction of the broken vessels
Initially the vessel gets broken, and then there will be a spasm within the blood vessels, effective for smaller blood vessels, and useful bc the spasm helps reduce blood loss for 20-30 min and allow time for the other mechanisms to occur bc they tkr a little longer
Platelets are formed elements within biffy coat, they play a key role in hemostasis bc they aggregate (clump together) and will form a plug that will temporarily seal a broken vessel wall
Under normal conditions, platelets don’t stick to each other, not gonna aggregate and not going to adhere to endothelium of the blood vessels
That’s essentially due to chemicals that are released by endothelial cells that inhibits platelet aggregation from occurring bc you wouldn’t want to form clots or mesh nets in areas that don’t need it
But when the endothelium is damaged, like in step one, collagen fibers become exposed, and platelets will begin to go through that process of adhering to one another
As platelets aggregate, release chemicals that help to induce aggregation of more platelets
Example of positive feedback mechanism that allows for the buildup of platelet aggregates that allows for platelet plug to form
Platelet plug, this is not really sufficient as sealing something large
Bc when it comes to platelet plug wall, platelets not held very close together, held loosely
Final stage, being able to form that fibrin clot, is the result of a multi step process that involves many factors
And so we can see that they’re clotting factors that are derived from platelets, damaged cells, and plasma, and ton of siff factors found in cascade
When it comes to the process, the simplified pathway, what we’re focusing on is the formation of a prothrombin activating
something that will come out of enzymatic cascade
Prothrombin activator will catalyze the conversion of prothrombin to the active enzyme thrombin
When we have thrombin, we have positive feedback loop that helps cascade that leads to more activators, we can thus amplify and build up concentration of thrombin
Thrombin will further catalyze another portion which is the transition of fibrinogen into fibrin
This translation, the molecules will form in soluble polymers
This step helps to induce polymerization
With polymerization, fibrin will act like glue and help to try and keep all the platelets together which will prevent the exit of formed elements like the erythrocytes shown here
Fibrin clots, these are really effective in sealing a hole or sealing a site of damage until a blood vessel can be permanently repaired
In illustration:
RBC caught in beds of fibrin
Impedes any excessive blood loss out of vessel side
Keep in mind transduction pathways
The idea of having a cascade of events that are dependent on the events that precede them, the concept of positive feedback, activating an enzyme, fibrinogen to fibrin is not generating an active enzyme, generating fibrin which is able to polymerize, which helps to prevent excessive loss of formed elements

Question 48

Cardiovascular diseases: intro

Answer 48

Cardiovascular disease:
Diseases that impact the heart or impact blood vessels
Vary with respect to how serious they are
Can be diseases minor, or can be really integral to life
Something that may impact blood flow to heart and brain = bad
Think about some possible ways in which you could modify or change something from cardiovascular system that may lower the likelihood of event taking place or some type of mechanism to treat that disease

Question 49

Cardiovascular diseases: intro

Answer 49

Cardiovascular disease:
Diseases that impact the heart or impact blood vessels
Vary with respect to how serious they are
Can be diseases minor, or can be really integral to life
Something that may impact blood flow to heart and brain = bad
Think about some possible ways in which you could modify or change something from cardiovascular system that may lower the likelihood of event taking place or some type of mechanism to treat that disease

Question 50

Cardiovascular Disease: Atherosclerosis

Answer 50

Cardiovascular disease atherosclerosis
Essnetially the accumulation of lipid deposits
Lipid deposits, or plaques will degrade the arterial wall and begin to destruct the lumen, or the opening of the blood vessel
This can have dangerous consequences when it comes to effective blood flow
In thinking about the process of atherosclerosis, there can be small, patchy, thickenings that are referred to as athremos, that makes the walls of arteries thicker and stiffer
There is a change in form and function
These changes are initiated by damages or damaging events that take place in endothelial cells
When endothelial cells are injured and have dysfunctional endothelial cells, that promotes the accumulation of lipids, which can oxidize with the innermost layer
The tunica intima, which is the innermost layer
This can result in an inflammatory response which can gave negative consequence
We have these damaged endothelial cells, they will transport and modify something called a low density lipoprotein, LDL, which delivers cholesterol to tissue cells from the blood
What ends up happening is an accumulation of LDL, and LDL oxidizes as well, which will damage neighboring cells, and from that damage recruit macrophages
Macrophages are professional eaters, which will become engorged with LDL in the process of phagocytosis
At that point they are referred to as foam cells
When it comes to next stage within this process, smooth muscle cells will begin ot go through cell division, taking place from the middle tunic, tunic media , and deposit collagen and elastic fibers
This will thicken most intimate layer
Then we end up with our plaques
Plaque will consist of dead and dying foam cells, which over time can protrude and begging to invade vessel lumen
With having that protrusion into lumen, going to start to decrease of effective blood flow and depending on where that blood meant to go, can have really harmful consequences
Vocab purposes:
We can see a blood vessel that has plaque formation where dashed line is
Also have something here that is called a thrombus
thrombosis = blood clot and that is adding on to decreased diameter of the lumen
Possible for a thrombus or clot to grow large enough to completely obstruct a small vessel or a piece of thrombus can break off and travel in the bloodstream and end up as an embolism
Embolism = fragment of blood clot wedges its way into smaller vessel and impede blood flow from that point on
Ex: pulmonary embolism

Question 51

Composition and Function of Lipoproteins

Answer 51

Cholesterol = important factor when considering athromas and the buildup of fatty plaque
Cholesterol = structural lipid
Not oxidized for fuel
Liver capable of making large % of cholesterol, remaining cholesterol comes from diet
Cholesterol basis in bile salts, and utilizes in digestion of fats, used for steroid hormone synthesis, and vitamin D
Cholesterol and transport from diff locations, cholesterol is nonpolar and is going to depend on lipoproteins as it means to move from place to place
Lipoproteins are classified into diff categories based on density
There are chylomicrons
Very low density lipoproteins
Low density lipoproteins
High density lipoproteins
Overall organization of the lipoprotein, they’re all going to have phospholipids, cholesterol, lipid category, as well as protein
The higher the proportion of lipid to protein, the lower the density
All you need in knowing % breakdown of these categories
Usually, each of this categories diff with respect to size (not important)
For very low density lipoproteins
Produced by liver
Transport lipids to adipose tissue
Its at the adipose tissue where they are stored
When these are removed from adipose tissue, they become LDL’s
LDL’s are going to carry cholesterol from liver to tissue to places that need cholesterol
For membrane structure or steroid synthesis (two common cholesterol purposes)
They’ll (the cells that LDL went to) absorb that LDL through receptor mediated endocytosis and then digest that LDL utilizing lysosomal enzymes and releasing the cholesterol for use
High density lipoproteins:
Begin in the liver and then the shells will travel into the blood to essentially carry cholesterol from tissue to the liver and as the HDl makes its way around, will pick up cholesterol from places in which it finds it and then the next time it circulates to the liver, liver will remove that cholesterol and essential eliminate it
HDL are used for removing excess cholesterol in the body
This comes into the concept of “good and bad cholesterol”
HDL are considered to be good as it helps to decrease the amount of cholesterol found which can potentially build up in blood vessels
LDL can result in build up of cholesterol that is there as if they are received at various locations and broken down, if they’re not used effectively, cna have harmful outcome
Like atherosclerosis

Question 52

Balloon angioplasty: treatment for plaque build up (atheroma) that blocks blood vessels

Answer 52

One way we can address plaques and that’s true something called a balloon angioplasty
Vessel surgical repair
In this process, there is a catheter that is threaded into arterial wall
Balloon that is found at the tip of catheter and balloon gets inflated
Through inflation of the balloon, there’s pressure that is applied against the atheroma, and that helps to widen the lumen which can help to resolve any issues with blood flow that would be resulted for the plaque
Benefit = less risky, less expensive
Risk: there is often restonesis
This means that the athromas, and these plaques, can grow back in this site nad obstruct the artery after a certain period of time lapses
So can help resolve a plaque, but those plaques/athromas can grow back.

Question 53

Stent and balloon angioplasty to address restiostesis (when plaque formation forms again (atheroma) after just balloon angioplasty is put in)

Answer 53

Something that helps to address that restenosis is the addition of a stent
The only difference here is that rather than just apply the balloon in order to exert that pressure and then remove it
Here wee have a balloon and a stent that gets put in an area in which we have plaque build up
So the balloon still gets inflated, but as the balloon inflates, its going to widen the stent, and the stents is going to widen the artery
The difference ihere is that when you have balloon angioplasty without a stent, the balloon gets removed, here the balloon is also removed but stent gets left behind and that helps to maintain that space, maintain the lumen, and help to increase blood flow
Stent is a modification of balloon angioplasty that can help restiostesis
Restiostesis is the reformation of atheroma (plaque build up that blocks vessels) after a certain period of time

Question 54

Cardiovascular Disease- Myocardial Infarctions

Answer 54

The myocardial infarctions (heart attack)
Heart attack leading cause of cardiovascular death in US
When it comes a myocardial infarctions
Thinking bout myocardium, which is the largest portion of heart wall
When there is damage to myocardium, that’s going to impact the efficiency of heart muscle contractions
How can that occur?
Damage to the myocardium can occur when it doesn’t receive blood
We don’t think about coronary blood supply when we think about systemic circulation in the pulmonary circuit in those examples
But important to include heart in those specific vessels as a component of systemic circulation
Heart needs blood too
Heart will be depending on ATP to carry out constant beating
Its autorhythmic, not depending on anything, constantly working, and doesn’t fatigue
Don’t want it to fatigue
Myocardial infarctions arise due to insufficient supply of blood to one part or more than one part of heart muscle
Through this deprivation of blood, myocardial cells don’t have oxygen they need to do the work of pumping blood throughout the body
As a result, muscle damage occurs which results in necrosis (death of that tissue), and cannot be repaired
Insufficient supply of blood can be caused by block of an artery, blood clots, anything that will impede movement to that region
Recovery is still possible if the damage was such that the heart can still contract in a functionally coordinated way
Something that may impact that aspect, like something in the cardiac cycle, that would be harmful
But if a small area of the heart is damaged but can still go through cardiac cycle, recovery is feasible

Question 55

Cardiovascular Disease- Aneurysms

Answer 55

Ex of an aneurysm
Aneurysm is the bursting of a major vessel
Over time, atrial walls can become thinner and blood flow can cause those weakened walls to swell and depending on the severity, can cause vessels to burst
If that vessel in question is very significant, like a cerebral artery, then the aneurysm event of cerebral artery can cause bleeding around the brain
From that brain bleed, there can be pressure that leads to death of that tissue
That can result in a hemorrhage based stroke
In the same way that the heart is really dependent on sources for energy, same for the brain
Lots of mechanisms that are body has in place in order to ensure that both of those locations get what they need in order to continue functioning effectively
Something that impacts blood flow to the brain can have really significant effects

Question 56

Cardiovascular Disease- Stroke

Answer 56

In that previous example, we were thinking about swelling and bursting of an artery
In terms of damage to the brain, that can also occur through another mechanism
Essentially, anything that interferes with blood supply to the brain can lead to a stroke
That can be through blood vessel bursting, but it can also be if the cerebral artery is blocked and that is blockage can occur through blood clot, and it could be a blood clot that breaks off and travels to an area in which the vessel diameter becomes too small for ti to proceed further, which is something we talked about
Or it can be a result of atherosclerosis
Something that will change the lumen opening through the build up of plaques

Question 57

Water versus air as the type of media used in order to facilitate gas exchange

Answer 57

When it comes to the discussion of breathing, partial pressure gradients drive gas exchange
When it comes to partial pressure we’re thinking about pressure exerted by a gas and the mixture of gases
Reference O2 and CO2 in all of our discussion of partial pressure gradients in this chapter
When we think about the type of media that is used in order to facilitate gas exchange, what we find is that air and water are not equal respiratory media
As a result, organisms will have different mechanism by which gas exchange can take place
Ex: the density of water is significantly higher than air
The viscosity (thickness) is higher than air
That’s going to have an impact on the ease of taking in this respiratory media through the branching that occurs within the respiratory system
When we think about other factors, such as the amount of oxygen that we find within water as compared to air, there’s much less of it found in water than in air
That means when it comes to respiration in aquatic organism, there must be a much higher efficiency in order to get as much oxygen as possible

Question 58

Respiratory Surfaces

Answer 58

In order for gas exchange to take place there needs to be movement off or across some type of respiratory surface
Go through few example of respiratory surfaces
Varying depending on needs of organism
Emphases in discussion in gills, tracheal system, and lungs
The media in which it is acquiring its gases from will also be talked about (water versus air in getting the gases of O2 and CO2 to be exchanged in those respiratory surfaces)

Question 59

Ventilation in Aquatic Animals (diff types of gills)

Answer 59

There is a ton of diversity when it comes to the structure and organization of gills
Gills serve as a site for gas exchange in aquatic animals
Gills are specialized extension of tissues
Meant to project into the water, and they can be simple and there’s a simple organization seen in echinoderms
Ex: sea star
They can also be more complex
When it comes to gills ,they help to increase surface area and that allows for the organism to extract a lot more oxygen form the water than would be possible from their body surface alone
Axelatol from earlier, that would an example of external gills
External gills = easy to see purtudying from the outside
Similar to the marine wom here
Not enclosed within the body structure like you would see if we were to remove the thorax of the crayfish
Disadvantage to having external gills, there’s a need for constant movement so that the gills the gills can come into contact with fresh water that has high oxygen content
When you have outward facing gills, they also have the propensity to maange more easily than those that are protected through something like exoskeleton
Not gonna go through much of the detail between a, b, and c other than the gills are organized, where they are located, and they deviate but the gills all serve the same purpose of helping with gas exchange and all serve with increase surface area for the exchange to take place as efficiently as possible

Question 60

Countercurrent exchange in gills of fish (between blood and water for oxygen diffusion)

Answer 60

These thin membranous plates are called lamella
When it comes each lamella, the blood flow is going to opposite the direction of water movements
Countercurrent aspect
So, this countercurrent exchange maximizes the oxygenation of blood and it does this by maintaining a positive oxygen gradient along the entire pathways
Blue side of blood is oxygen poor, and moving towards oxygen rich (red sie)
When it comes to that blood flow, blood is always less saturated with oxygen than the water it meets
Quantivalty, the oxygen values in blood are going to be always lower than the oxygen level in water above
Bc blood is always less saturated with oxygen than the water flowing near it, every single time it comes into close proximity to these values, oxygen is going to diffuse along the lamella
Ex: 30 oxygen value in water to 20 oxygen value in blood
Going to result in oxygen diffusing down into blood
Even when the value increases bc it received some oxygen from the water, the value is still going to be lower than value at the new position
Going to continuous promote net diffusion of oxygen into the blood
This helps to ensure that even when the oxygen concentration goes up in the blood, there is still more and more oxygen that gets dropped off, that ensures the blood leaving the gills has nearly as high as oxygen content as the water that entered it
Really efficient mechanism
Driven by the fact that blood flow and water flow opposing one another

Question 61

Tracheal Systems in Insects

Answer 61

Tracheal system seen in insects
We are utilizing grasshopper as example
Tracheal system composed of small branched air ducts or trachea
Trachea will branch even further in tracheoles
These tubes will transmit gases throughout the body, and the tracheoles are in direct contact with the individual cells of oxygen will diffuse directly across the plasma membrane, as well as CO2 to move in the opposite direction
Air passes into the trachea through specialized openings on exoskeleton
Referred to here as external openings or spiracles
Due to the direct interaction of the tracheoles with the body cells, the grasshopper is not going to depend on the open circulatory system in order for these particular exchange of gases to take place

Question 62

The Mammalian Respiratory System

Answer 62

Here we have the mammalian respiratory system
Principal Organs:
Nose in nasal cavity
Phyryx
Larynx
Trachea
Bronchi
Lungs
There is the thoracic cavity in where events will take place
When we’re thinking about respiratory system, a lot bit of form and function to consider as well in addition to overall roles
Nasal cavity:
conduite for air to take air in and breathe air out
Warm and moisten air
Helps with filtration
Phyryx:
Space
Phyryx overall bc phyrx can be broken down into region proximal to nose, mouth and throat, but in general this is a conduite for air
For air to pass through
Larynx:
Esophagus
Also going to help with the proper routing for food and air
Helps with production of sound
Warming, moisiting air and protecting the air ways
Trachea
Great ex of rom and function
Has the C cartilage based rings that are firm
Helps to support the air that flow through bc if it was easy to collapse that would really impact our ability to take in air and let air out effectively
When we’re saying conduit for air, we mean pathways in which air can travel through
Bronchus
Will branch out into smaller bronchioles
Still allowing for air to flow through
Idea of the mammalian respiratory system
We have all of these passageways/conduites for air to travel
Can modify air to a certain extent through diff ways in respiratory system
Air will lead us is to sites of gas exchange within our bodies

Question 63

The Mammalian Respiratory System: more in depth (last paragraph explains it well!)

Answer 63

We’re taking in all of these air
Breathing out air
But again what really matters is the opportunity to exchange gases
Want to drop off what we don’t need and pick up what we do need
When it comes to mammalian respiratory system, two major zones
There’s the conducting zone
conduites/passageways for bringing air through the boy or on its way out of the body
Conduites up until the terminal bronchial, last point where conduites are found
Thinking of cleaning, humidifying, warming the air
Then we transition from conducting one to respiratory one
Respiratory zone
Where gas exchange takes place
Exchange is going to occur at these alveoli that are found
Going to be in close proximity to the cardiovascular system and the pulmonary capillaries and that’s what’s going to allow for that exchange to take place
When we think about that exchange and ventilation, think about close relationship between the vessels within the cardiovascular system and the components in the respiratory system for exchange to take place between them
Pick up oxygen we have been taking and traveling through conducting zone into the respiratory zone, into the alveolar sacs, more specially alveoli, and also want alveoli to collect metabolic waste that we were generating in processing we needed to to sustain everyday lives (CO2)
What is line of demarcation from conducting zone to respiratory zone
Instead of terminal bronchiole, after conducting zone, bronchioles referred to as respiratory bronchiole
Pulmonary venule: associate with lung behavior
When it comes to the pulmonary venule
Oxygen rich so we know that the direction of movement should be away from the alveolar sacs
Pulmonary arterial should be heading towards the pulmonary capillaries as it is carrying oxygen poor blood to be replenished with oxygen rich
Where we have purple, should be a site in which we have a mixed site of content of oxygen
A little bit less of one and the other
Capillaries provide an opportunity for exchange to concur
At the capillaries, we should be dropping off CO2 coming through via pulmonary arteriole
We should be receiving oxygen that is housed with alveoli, which will bring oxygen content up to the pulmonary venules (vein) and then we’ll bring that back to left side of the heart where we can conduct that oxygen rich blood to the rest of the body

Question 64

Breathing ventilates the lungs

Answer 64

The process of breathing and then benefit that breathing has
Breathing responsible for lung ventilation
Breathing is inhalation and exhalation

Question 65

How an Amphibian Breathes

Answer 65

When it comes to amphibians, they will utilize positive pressure breathing
In positive pressure breathing, that is where air is forced down the trachea
Amphibian will fill up oral cavity will air
Close their mouth and nostrils, they will elevate of the floor of that oral cavity and then push air through the lungs
Similar to filling up a balloon
Forcing air into that space until it expands
Analogous to forcing air into a person lung by performing mouth to mouth resuscitation

Question 66

How a Bird Breathes

Answer 66

Bird respiratory system is highly efficient
Birds will have air sacs
A posterior and an anterior air sac that extends between the internal the organs and into the bones
Breathing occurs within two cycles that are broken up into first inhalation exhalation and second inhalation exhalation
In cycle one, what we have first is air heading into the trachea, and that air is going to head towards the posterior air sacs and will expand and they fill with air and exhaled in step two into the lungs
At that time posterior air sacs will deflate as it exhaled
First inhalation and first exhalation
Cycle two: air is drawn from the lungs and it will head towards the anterior air sacs which will expand and it will be exhaled from anterior air sacs into the trachea
The movement of air is always in the same direction
Posterior to anterior
Cycles take place simultaneously
So during inhalation, fresh air gores int posterior air sacs at the same time that the air that as from the previous breath in the lungs moves into the anterior air sacs
During exhalation, the new air moves from the posterior air sas to the lungs at the same time that the air in the anterior air sacs is exhaled from the body from the trachea
Having this unidirectional airflow will maximize the efficiency birds have
Able to extract a lot of oxygen from air as compared to humans
Beneficial for the heights birds cna take bc oxygen availability reduces as altitudes go up

Question 67

Pulmonary Ventilation

Answer 67

Inspiration:
Muscles that are contracting
Muscle contraction is important bc the muscle contractions are going to change the volume of the thoracic cavity
Thoracic cavity
The space that’s in there will increase
The lung volume increase bc lungs are expanding
With that increase in volume, they were be a decrease in pressure
Pressure within the lungs down down when volume within the lungs goes up
As the lung volume increases and the pressure within the lungs goes down, it goes down to such an extent that that the value of pressure seen within the lungs is lower than that of the surrounding environment
Air wants to flow down the pressure gradient, so as a result air will enter the lungs
Expiration:
Passive process in which the muscles are going to relax and the thoracic cavity will decrease
As the thoracic volume decreases, lung volume decreases, and when we see this decrease in volume, we see an increase in pressure
With that increase in pressure, the value found within the lungs (pressure) exceeds surroundings environment
So air will flow out of lungs
Capitalizing on changes within volume, how that impacts pressure, and thus the pressure gradient
In between breaths:
Pressure that we find within the lungs is equal to that of the surrounding environment
No pressure gradient, so no air movement

Sum up: CO2 concentration goes up bc of, in this example its exercise so a lot of ATP is needed and generated, which results in CO2 as a product, and CO2 makes more protons in blood, which decreases the pH
medulla and sensors in major blood vessels detect decrease in pH from its regular pH of 7.4 and medulla responds by increasing rate and depth of ventilation by causing diaphragm to inhale and extract more
-as a result, we breathe more so we can take in more O2 and out more CO2, resulting in pH in the blood going back to normal

Question 68

How a Mammal Breathes

Answer 68

Add on from inspiration expiration slide bc it gives us a sense of what the diaphragm is doing and what rib cage is doing
What we can see is that as we inhale and the muscles are contracting, we’re opening up space within the thoracic cavity, the diaphragm contracting and it’s going down
Diaphragm serves to separate the the thoracic cavity from abdominal cavity
So as we breathe in, diaphragm goes down, rib cage expands and we’re filling all of this space and in filling it in all with space, we will decrease pressure which will allow air to go in
Exhalation = relaxation
Going to decrease the amount of space seen within thoracic cavity and as diaphragm relaxes it moves upwards and we see there is room/space so diaphragm positing contributes to the amount of volume that can be found within the thoracic cavity
Through decrease in volume, increase in pressure which promotes the movement of air out of the body
Adding on the differences in terms of diaphragm positioning, can take a look at rib cage
We can inspiration and expiration interhcarbly with inhalation and exhalation

Question 69

Pulmonary volumes and capacities

Answer 69

Pulmonary volumes and capacities, providing a metric about pulmonary ventilation that we can use as a way to assess the severity of certain types of respiratory diseases
First one is tidal volume
Amount of air that is inhales and exalted in one cycle of normal quiet breathing
That’s about 500 mL
If we go above 500 mL in either inspiration and expiration
That would be called the reserved volume
The amount that we can forcibly inhale is more that what we can forcibly exhale
What that means is that even when we force exhilaration, there is still a volume of air that remains in the lungs that can be voluntary exalted
This is residual volume
Some measurements based on capacity, involve formula
One is vital capacity
Is the max ability to ventilate
Encompassing inspiratory and exteriority and tidal volume
So basically normal breathing (tidal volume) + whatever you can force out inhaling and exhaling
Summation of all of those events which can provide info about pulmonary health
Inspiratory capacity: getting info about the max amount of air that can inhaled after a normal tidal expiration
Tidal volume and inspiratory reserve volume
Starting from tidal volume and then the max we can force in through inspiration
Functional residual capacity:
Air in the lungs after normal quiet breathing
In the absence of max effort
Which is why we’re including expiratory reserve volume within this calculation
Total lung capacity: tells us the max amount of air that’s found within the lungs

Question 70

Control of Breathing in Humans

Answer 70

Breathing is an event that we don’t need to think about
Our body is working to maintain homeostasis
There is control mechanisms in place
In this ex:
Normal blood pH = 7.4, which will be set point
We fall below set point, and blood pH goes down due to increase in CO2
Provide the example of exercise; during exercise there is an excess of CO2, metabolic waste, bc we are trying to turn out as much ATP to feed tissues and in doing so we generate CO2
CO2 will react with water nad lead to an increase of concentration of protons
pH shift can be detected by diff things
Medulla can detect changes in pH
Sensors of the carotid arteries and aorta and can also detect changes in blood pH
These responses can ultimately signal to the medulla oblongata that is should the rate and depth of breathing
As a result, signals from the medulla will cause the muscles to change
Diaphragm will contract and relaxation in such a way that the rate and depth of ventilation goes up
So we’re breathing more so that we can take more oxygen and get out more CO2 and in doing so CO2 levels within the blood go down and the pH in the blood will come back up to norma value
One way we can control breathing in the body and how our body will respond in order to ensure our blood pH does not veer to too acidic or too basic

Question 71

Adaptations for gas exchange include pigments that bind and transport gases

Answer 71

Adaptation for exchange include pigments that bind and transport gases
Now we’re shifting gears into what is directly responsible for transporting the oxygen and CO2 in various places in the body
Thinking about the role of metabolism
Metabolic require that blood be able to move large amount of O2 and CO2

Question 72

Coordination of Circulation and Gas Exchange

Answer 72

Walk through the process circulation and its relationship w/ gas exchange
Taking in air from right hand side of lung
Able to do this due to changes within the thoracic cavity that allows from air to head down their partial pressure gradient
The air will make its way into alveolar space and the O2 will go down its partial pressure gradient and will go down its partial pressure gradient from alveolar space to alveolar capillaries, which have a very close spatial relationship
At this point, we now have our vessels that are going to have increased concentrations of oxygen (by getting O2 from alveolar capillaries) and those pulmonary veins will make their way back to heart
Now we have left atrium, our blood is going to drop down into left ventricle and then eventually be pumped out through aorta
That blood that’s oxygen rich will head out ot rest of the body
That is systemic circulation
At systemic capillaries, we will have an exchange take place bc at the body tissues, these will be sites where work has been done and ATP has been generated so metabolic waste has been made
So we need more of that final oxygen acceptor, so we’re going to take oxygen from oxygen rich vessels and drop off the CO2 produced from carrying out everyday metabolic actions
Now we have oxygen poor blood, that will make its way through the body ultimately heading towards pulmonary arteries and those pulmonary arteries are going to head towards the alveolar capillaries
At this point we’re oxygen depleted and CO2 rich and we want to get rid of CO2 and get more O2
So that CO2 will diffuse down its pressure gradient, heading into alveolar space, and from there can be exalted
Within this process, there are technically two sites of respiration
There’s external respiration, which is the pulmonary gas exchange that takes place
And then there is internal respiration, which is the gas exchange occurring at body tissues

Question 73

Pressure gradient connection in gas exchange and circulatory system

Answer 73

Adds on the actual values of pressure seen for our gases of O2 and CO2
The actual numbers are not essential
Focus on is the fact that the partial presence gradient exists and that is what drives diffusion from one location to another across respiratory membrane
Looking for confirmation that hte difference is what is driving movement form what sight to the next
Oxygen gradient:
Stepper than the CO2 gradient but equal amounts of the gases are exchanged
Difference in solubility of CO2 that is 20x more soluble in plasma and alveolar fluid that oxygen is
Need more oxygen to equal them out
Do see a diff in CO2 and O2 in gradinece but that is bc of difference in solubility
These values and the differences that we see as we migrate from one space to the next will elt us know the direction of gas will flow
The stark contrast of O2 vs. CO2 has to due to strictly with the level of solubility of the level of CO2 gas compared to O2
As equal amounts of inhaled/exhaled

Question 74

Respiratory Pigments Hemoglobin

Answer 74

Focus on hemoglobin as a respiratory pigment
Respiratory pigment = proteins that transport oxygen, greatly increase the amount of oxygen that blood can carry
Hemoglobin is a polypeptide that is reached quaternary level of structure bc there is 2 or more polypeptides involved
Consists of two alpha chains and two beta chains
Each chain is conjugated with non protein heme group
Heme group is what binds oxygen to an iron ion at its center
If each heme is carrying one molecule of oxygen, a hemoglobin molecule can carry up to 4 oxygens at a time

Question 75

Hemoglobin Dissociation Curves: 2 graphs, one shows the pressure comparison in diff parts of the body with the amount of oxygen saturated in hemoglobin, and graph 2 shows the pressure of oxygen with diff pH and the oxygen saturation in hemoglobin

Answer 75

Here we have hemoglobin dissociation curves, which is a way to think about the relationship between hemoglobin and oxygen
Hemoglobin has those 4 polypeptide chains, have iron containing heme group and they can interact with up to 4 molecules of oxygen
Oxygen loading:
Rapid process and reversible process
When you have hemoglobin and oxygen combined = oxyhemoglobin
When hemoglobin releases oxygen = deoxyhemoglobin
After the first oxygen molecule binds to iron, the hemoglobin molecule will change shape and as a result, it more readily takes up additional oxygen molecules, which helps to enhance the saturate state
This is comparable to a concept that is discussed: coopertivavity
In which the binding event of a substrate is going to enhance the other subunits in their ability to interact with substrates at allosteric sites
Here we have hemoglobin, essential oxygen hemoglobin dissociation curves
Helps us understand the relationship between hemoglobin and the partial pressure of oxygen at diff locations
If we look at the axes:
One axes telling us the partial pressure of oxygen dissolved in the fluid that is proximal to the hemolgin, so surrounding the hemoglobin
Y axis = oxygen saturation
100% oxygen saturation in hemoglobin, that would mean 4 oxygens
Take a look at diff locations in which we have our hemoglobin
If we are at the lungs here
Then what we’re saying there is that the partial pressure of oxygen is high (100 mm Hg), and hemoglobin is fully saturated
Based on where it hits on the graph
If more oxygen present, nore oxygen is bound
When it comes to the process of the strength of that finding, the idea of cooperativity will work in both direction, just as readily as it will pick up additional oxygen in oxygen rich locations, as it starts to drop off oxygen, will be swift change in saturation, which si why there is a more sigmoid curves seen in these dissociation curves, which is the type of trend that are also see for enzymes that display cooperativity
If we are in tissue in other organs where the partial pressure is lower
Then hemoglobin becomes less saturated,
if we are at tissues during exercise, we expect the least amount of saturation of oxygen in hemoglobin bc those are areas that really depend on oxygen in order to continue going through those events and there’s also depending on the ability to release CO2 too
Here we have diff examples, lungs, tissues at rest, tissues during exercise and pw saturation of hemoglobin shifts at these diff locations
The binding strength or the way in which those shifts occur is going to be influenced by the cooperative nature of hemoglobin oxygen interaction
On the right hand side (second graph)
We have a dissociation curves that thinks about the relationship of pH of the blood with the amount of oxygen that will be found bound to the hemoglobin protein
Under standard physiological conditions, pH should be = 7.4
Here we have an example of where pH goes down to 7.2 (red line)
Our level of saturation at the same amount of partial pressure but varying pH conditions, we don’t have same exact of oxygen bound
We are going to see a little less oxygen bound when the pH is lower than when we are at normal pH conditions
This would be an example of the Boer effect
When we have decrease pH that causes the dissociation curve to shift to the right, which is the soldi line, and that response the Boer effect or Boer curve

Question 76

Factors that Influence Oxygen Unloading

Answer 76

As was evident in the dissociation curve in the left of the previous slide, hemoglobin doesn’t unload the same amount of oxygen to all tissues
Difference of tissues at rest vs. tissues art exercise
Several factors that affect the rate of dissociation events going to occur
That should make sense even without utilizing a dissociation curve
At the top hand side of this, we have normal conditions, normal body temp, proton concentration or partial pressure of carbon dioxide
As far as illustration goes, only as good as overlaying a difference
Let’s go through diff factors:
Temp influences unloading bc what we find is that active tissues are warmer than less active one
When thinking about metabolic processes, there is release of energy that cannot be used and released in the form of heat
So active tissues are warmer than less active ones which results in extraction of more oxygen from blood passing through them
Increase temp increases the amount of oxygen unloading at that sight
When it comes to pH, we can kind of consolidate panels b and c, because when it comes to active tissues, they generate CO2, and extra CO2 raises the concentration of protons when we think about how CO2 interacts with water and ultimately lowers the pH
CO2 in water produces carbonic acid which will dissociate into bicarbonate and protons
This event weakens interactions between O2 and hemoglobin and it is more pronounced in systemic capillaries than in lungs and this the Boer effect mentioned before
All of these factors will cause more oxygen unloading and these factors are going to influence the 3D structure the hemoglobin protein and as they do this they will lower the affinity than hemoglobin has on oxygen
Graph of normal temp, H+ concentration or pressure of CO2 (since they both result in more protons → more acidic → weaker interactions between hemoglobin and oxygen → more oxygen unloading) vs graph of increased body temp, H+ concentration or pressure of CO2, we see that these vents will cause the dissociation curve will shift to the right like earlier slide
these factors are usually highest within the systemic capillaries and that makes sense bc these are locations in which the goal is to release oxygen molecules
Collectively, these events lead to Boer effect (after first O2 molecule, oxygen is more easily released from hemoglobin) to enhance oxygen unloading by weakening the desire for oxygen to stay associated with hemoglobin protein

Question 77

Systemic CO2 transport (CO2 coming out of tissue into erythrocytes in systemic circuit in capillaries (to turn into bicarbonate and be released via antiport facilitated diffusion with bicarbonate coming out to plasma Cl- coming in and , release H+ to bind to heme in hemoglobin to help oxygen release from hemoglobin to tissue)

Answer 77

So let’s begin with the movement of CO2 within systemic circulation
Start with mitochondria- site of aerobic respiration
Aerobic respiration:
Breakdown of organic fuels through utilization of O2 and drives production of energy through the form of ATP
In addition to making ATP, CO2 will be a byproduct
There’s a buildup of CO2 in tissue cells
CO2 will diffuse down partial pressure gradient out of tissue cells and into the systemic capillary where it can be carried in the bloodstream
It can diffuse from tissue to systemic capillary in a few diff ways:
It can be dissolved in the plasma
It can be chemically bound to hemoglobin
When it comes to this binding event, the CO2 does the binding at the amino acid location of the hemoglobin rather than the heme, so CO2 binds to the globin, oxygen binds to the heme so there’s no competition of transfer for these two gases
bicarbonate ions in the plasma after CO2 is diffused into erythrocytes, but we need to be able to convert CO2 into bicarbonate ions first
The process of CO2 conversion into bicarbonate
Majority of CO2 is going to be hydrated, which will lead to H2CO3 (carbonic acid)
Carbonic acid = unstable, so they are going to dissociate into bicarbonate ions and protons (H+ + HCO3-)
Happening in erythrocytes, but can also take place within the plasma,
However the erythrocytes contain the enzyme carbonic hydrase, ans that helps to catalyze the reaction more readily than in the plasma
The protons that are released in this process are going to bind to hemoglobin, and this contributes to the Boer, which enhances oxygen’s release
The protons released during dissociation are not the significantly contributing to the pH of blood, bc we’re tying it up in this binding event with hemoglobin
Once you have carbonate, it needs to head into the plasma from erythrocyte, this movement is going to be coordinated between bicarbonate movement out of erythrocyte, and Cl- ion movement into the erythrocyte, to create a balance of ion transport
Referred to as a chloride shift and occurs through a protein that is found on the erythrocyte and allows for antiport facilitated diffusion
Antiport = bc the movement of these ions in opposite direction
Facilitated diffusion: no utilization of energy so not active transport but rather diffusion that’s facilitated through the utilization of a protein
Antiport facilitated diffusion as bicarbonate goes out and Cl- goes in

Question 78

Pulmonary CO2 transport (how in the pulmonary circuit, when we are releasing CO2 and getting O2 from lungs, bicarbonate from plasma goes into erythrocyte and with H+ becomes CO2 again, which makes hemoglobin free of H+, which is good as it allows for oxygen to bind to it (as H+ binding to hemoglobin when there’s already oxygen on it in systemic circuit and needs O2 to be released) and CO2 will then be diffused down pressure gradient into alveolus to be taken out of body when exaled

Answer 78

CO2 transport within pulmonary circulation
So for pulmonary circulation, notice the change in direction thats seen through protein that’s here
Bicarbonate coming in and Cl- leaving bc now we need to load that bicarbonate back into erythrocyte so we can convert it back into the form that is will take as it exits out of the bloodstream into the alveolus, which will be in the form of CO2
Once we’re in the erythrocytes, we have bicarbonate that form with H+, and forms carbonic acid
Utilizing carbonic anhydrase again which will serve to split carbonic acid into water and CO2
Have CO2 release
This reaction frees up carbon dioxide which can be diffused down its gradient along its partial pressure gradient into alveolus
Amount of CO2 transported in blood is affected to the degree of oxygen that is found there
So as a reminder, this is not due to competitive binding bc oxygen and CO2 do not bind hemoglobin in the same way and location
This phenomena is referred as the Haldane effect and reflects greater ability for hemoglobin that contains less oxygen bound to it to form carbon menahememoglobin
As CO2 comes in from the systemic blood stream, its binding causes more oxygen to dissociate from hemoglobin into tissue
This dissociation allows more CO2 to bind with hemoglobin
One more thing to notice is that when it comes to this conversion back to CO2 is that we’re utilizing the same enzyme- carbonic anhydrase
Can be used for a reversible reaction