Circulation and Gas Exchange Flashcards

Question

Cardiac Cycle: Isovolumetric Contraction

Answer 1

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

Answer 2

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

Answer 3

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)

Answer 4

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

Answer 5

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

Answer 6

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

Answer 7

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

Answer 8

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

Answer 9

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

Answer 10

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

Answer 11

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

Answer 12

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

Answer 13

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

Answer 14

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

Answer 15

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

Answer 16

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

Answer 17

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

Answer 18

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

Answer 19

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

Answer 20

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

Answer 21

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

Answer 22

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

Answer 23

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

Answer 24

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

Answer 25

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

Answer 26

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

Answer 27

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

Answer 28

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.

Answer 29

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

Answer 30

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

Answer 31

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

Answer 32

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

Answer 33

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

Answer 34

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)

Answer 35

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

Answer 36

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

Answer 37

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

Answer 38

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

Answer 39

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

Answer 40

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

Answer 41

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

Answer 42

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

Answer 43

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

Answer 44

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

Answer 45

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

Answer 46

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

Answer 47

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

Answer 48

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

Answer 49

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

Answer 50

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

Answer 51

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

Answer 52

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

Answer 53

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

Answer 54

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

Circulation and Gas Exchange Flashcards

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