EK B2 Ch4 Circulatory System Flashcards
circulatory system
transport system! transports hormones, Transports metabolic wastes to kidneys for filtration by excretory system
blood
Blood is considered a connective tissue****
- Composed of cells and plasma
- Two cell types: red blood cells and white blood cells
- Centrifugation will separate cells (in pellet) and plasma (in supernatant), pellet is lower down part and supernantant fluid floating above where plasma the watery part of blood
plasma
- ~90% water, why changing blood volume is very much about reabsorption of water*
- Contains proteins, hormones, nutrients, salts, and metabolic wastes
- Osmoregulatory proteins: maintain osmolarity, blood volume and pressure
- Albumin is a major osmoregulatory protein
- Albumin also a carrier protein for fat-soluble hormones and cholesterol
- Many antibodies in gamma-globulin fraction, fraction when spin blood called gamma-globulin fraction
- Clotting proteins (prothrombin, fibrinogen, etc.)
osmoregulatory proteins
needs to be a certain solute concentration in blood to hold enough water in blood, like with kidney proteins don’t get filtrated out, lot of filtration and fluid goes into kidney but don’t want all of the water to go into filtrate so having some osmotic pressure is so important! proteins and other solutes as well help to maintain blood volume, maintaining osmotic pressure of blood
osmosis
drive of water to go where more solute, form of passive transport
albumin 1
very big doesnt ever enter nephron!
- circles around carries fat soluble hormones and cholesterol (hydrophobic molecules not happy in blood stream itself, in aqueous part of blood)
- carrier protein for fat soluble molecules to float around in aqueous environment of blood do can hitch a ride on albumin
serum
Plasma minus clotting proteins, technical difference whether clotting proteins are present or not
gamma-globulin fraction
• Many antibodies in gamma-globulin fraction, fraction when spin blood called gamma-globulin fraction where antibodies would be if looking for antibodies, one treatment for covid ppl experiment with
Clotting proteins
• Clotting proteins (prothrombin, fibrinogen, etc.)
Red blood cells
• RBCs = erythrocytes formal name
red blood cells 2
- No nucleus or organelles (both are lost during RBC development) as they mature lose all nucleus and organelles, become specialized machines for carrying oxygen meaning get stuffed with hemoglobin
- Contain hemoglobin, which binds O2
- Hemoglobin confers red pigmentation to RBCs and blood
- RBCs are continuously generated in red marrow
- Lifespan is ~120 days
- Old and damaged RBCs are removed from circulation by the spleen and liver
hemoglobin
makes red blood cells red, so the red blood cells are born in bone marrow, center of long bone are marrow, where all red and white blood cells are generated from stem cells, red blood cells then circulate and after they circulate for about 120 days get removed by spleen and liver
anemia
- Anemia = reduced number of RBCs
- Low hemoglobin → lack of O2 → weakness and fatigue hemoglobin carries oxygen, so low of this feel weak and fatigued not getting enough oxygen
- Three general causes of anemia =
- Decreased RBC production: iron deficiency anemia, pernicious anemia (low vit. B12) • Increased RBC destruction: hemolytic anemia (e.g., sickle cell anemia)
- Loss of blood due to bleeding (hemorrhage, internal bleeding)
- Hematocrit = volume of red blood cells/ total blood volume
- Low hematocrit could signal anemia or malnutrition
3 reasons why anemia occurs
- Decreased RBC production: iron deficiency anemia, pernicious anemia (low vit. B12). every hemoglobin needs iron in it 2. Increased RBC destruction: hemolytic anemia (e.g., sickle cell anemia) -red blood cells destroyed, cells because their is an abnormality in hemoglobin, cells sickle form crescent shape cannot carry oxygen as well, role up to crescent shape, tiny ability, stick in capillaries very painful come into ER With sickling crisis genuinely need opioid painkiller, someone just telling us asked about it - get lots of transfusions, then have all these complications with transfusions, can start getting autoimmune complications, so different causes of death for sickle cell anemia 3. Loss of blood due to bleeding (hemorrhage, internal bleeding) -any kind of internal bleeding, lots of elderly ppl have anemia, clue have some slow internal GI bleed going on that needs to be investigated, also plenty of women of reproductive age get mild anemia monthly lots of ways in which anemia can trigger somethign else going onw ith bleeding
circulatory system 1
- Circulatory system moves O2 and nutrients to tissues, collects wastes
- Transports oxygenated blood from respiratory system
- Transports nutrients absorbed from digestive system
- Transports metabolic wastes to kidneys for filtration by excretory system
- Transports hormones from endocrine system
- Critical role in thermoregulation, maintains temperature in tissues
- Circulatory system is closed in vertebrates (heart and vessels form a complete loop)
- Main elements are blood, blood vessels, heart
white blood cell 1
- WBCs = leukocytes
- Generated in red marrow
- Are characterized as granular or agranular
- Granular WBCs are the -phils all given last phrase “phils”
Neutrophils
are phagocytes: eat bacteria, dead cells, and debris, most common WBC work horses of white blood system
Eosinophils
• Eosinophils respond to parasitic infections, allergic reactions (stains red w/ acidic eosin) white blood cells dedicated to responding to parasitic infections, sign so much mroe common and important in our past, here living in western context right now dont see as many but our ancestors dealt with many more parasitic infections, basophilis more improtant medating allergic or inflammatory responses
Basophils
mediate allergic and inflammatory responses (stains w/ basic dye)
Agranular
WBCs are lymphocytes (B and T cells) and monocytes/macrophages
- Lymphocytes are B and T cells and mediate the immune response= responsible for adaptive immune activity
- Monocytes/macrophages are professional eating (phagocytic) cells
- Leukemia = inappropriate expansion of WBCs in marrow = cancer
- Pus = bacteria, live and dead neutrophils and other WBCs at infection site
granular vs agranular
agranular doesn’t have dots, granular does have dots
monocytes
grow up to be macrophages but both are phagocytic, like neutrophilis go around chomping up debris
leukemia
lymphocytes are a subcaterogy of leukocytes**** so there leukemia is an issue with leukocytes, inappropritate proliferation of white blood cells or leukocytes in bone marrow***
pus
bacteria, live and dead neutrophils and other WBCs at infection site sometimes sign of infection, reason why have a lot around an area some kind of infection or pathogen* sign you are responding to it but depending how bad infection is if huge amount of pus signals huge underlying infection
platelets
- Platelets are cell fragments, not full cells! only fragments of cells are platelets!!!
- Lack a nucleus in mammals*** question passage talking about some protein found in nucleus if carry out etc ask about genetics, question researchers couldnt study this protein and ex associated types of cells so anything involving nucleus couldn’t study in platelts because do not have a nucleus
- Critical for clotting
clotting/coagulation cascade 1
• Requires Ca2+, platelets, and a zymogen activation cascade cascade:
- At site of injury, blood vessel first contracts, reducing blood flow to limit amount of gushing and blood loss
- Platelets come and stick to wounded region → attract more platelets → forms a temporary clot (so get a cut it bleeds kind of stops bleeding after a while, difference to scab later, initial stopping of gushing blood is thanks to platelets) THEN wound itself and platelets send out molecules signaling to start clotting cascade, one zymogen becomes activatd becomes proteases, then cuts next zymogen and that becomes activated and cuts the next one, whole series of reactions, know end of cascade!
- Clotting cascade forms more robust fibrous clot
- Many clotting factors are zymogens that are inactive proteases
- Zymogen is cut → becomes active protease → cuts and activates the next zymogen
6. Platelet/clotting factors cut prothrombin to thrombin
7. Thrombin cuts fibrinogen to fibrin
8. Fibrin is insoluble and precipitates from blood, forming a sticky, fibrous clot
9. Hemophilia results from defects in clotting factors
- All clotting proteases are made in the liver
prothrombin
activated in blood clotting cascade to thrombin, and then thrombin cuts fibrinogen to make fibrin*
fibrin
material that makes up scab
clotting cascade 2
- mutation in gene for any of those proteins= end up with hemophilia
10. All clotting proteins/proteases are made in the liver*
arteries
A artery A for away, carry blood away from heart
- Arteries carry blood away from heart
- Arterioles are smaller arteries
veins
VENULES= smaller veins carry blood towards from heart
3 main types of blood vessels
• Three main types of blood vessels: arteries, veins, capillaries when blood leaves heart goes to = Arteries → arteriole networks → capillary bed → venules → veins
capillaries
-walls only one cell thick, walls made of Endothelial cells
• Capillaries are the smallest blood vessel (one cell thick)
questions asked previous about circulatory, in certain disease if someone gets blood clot in capillary and clot to come loose and travel where does it go next?
so then next goes to venules, if clot forms in venules where would it go from there answer would be a vein*
blood vessel structure
Three layers in a blood vessel=
- Endothelial layer lines the vessel
- Smooth muscle layer surrounds endothelial layer
- Connective tissue layer surrounds smooth muscle layer
- Arteries/arterioles have thicker walls (carry higher pressure blood) blood is under way higher pressure
- Veins/venules have thinner walls (carry lower pressure blood) thinner walls, blood moving through them is under lower pressure
- Capillary is just endothelial layer- all exchange with tissues takes place at layer of capillaries!!! gasses diffuse, no oxygen and carbon dioxide crossing in and out of arteries or veins for that matter becuase walls are too thick
- Gases diffuse through thin capillaries, but cannot pass through thick arteries and veins
- Capillaries often have pores, larger molecules and cells can sometimes pass
arteries v veins pressure wall thin vs thick
- Arteries/arterioles have thicker walls (carry higher pressure blood) blood is under way higher pressure
- Veins/venules have thinner walls (carry lower pressure blood) thinner walls, blood moving through them is under lower pressure
capillaries can be leaky diffuse…..
capillaries can often be leaky, when start to dilate can have larger molecules leaking out into intersitial area, when dilate allows nuetrophils and other cells to escape from capillary and go out into surrounding area to help chomp up debri and bacteria
- Gases diffuse through thin capillaries, but cannot pass through thick arteries and veins
- Capillaries often have pores, larger molecules and cells can sometimes pass
Vasodilation
Vasodilation → increased vessel diameter → reduces blood pressure
Vasodilation → more heat exchange with tissue/organ smooth muscle relaxes
Vasoconstriction
smaller vessel diameter, inc blood pressure, smooth muscle contracts= what is responsible for making diameter smaller or larger
Vasoconstriction → smaller vessel diameter → increases blood pressure
Vasoconstriction → less heat exchange with tissue/organ
Vasoconstriction vs vasodilation
- Smooth muscle around blood vessels can contract and relax (mainly arteries/arterioles)
- Can regulate blood flow to each tissue as required, underlying mechanism for sympathetic vs parasympathetic smooth muscle lead to artery dilate not focused on digesting lunch don’t need as much blood flow to digestive system, so smooth muscles around arteries leading to digestive system will contract and you will get vasoconstriction, way a body prioritizes one function versus another depending on what is going on at the moment, autonomic nervous system controls that parasympathetic vs sympathetic nervous system determines priorities for blood flow
vasconstriction vs vasodilation 2
also contribute to heat being exchanged! opening up of vessels lets more heat out, vasoconstriction way of conserving heat!
- Controlled by autonomic nervous system
- Vasoconstriction → less heat exchange with tissue/organ
- Vasodilation → more heat exchange with tissue/organ
heart
- Heart has four chambers
- Two atria, left and right, receive blood from tissues
- Two ventricles, left and right, pump blood towards tissues
- Septa are muscle walls that separate ventricles and atria
- Valves between atria and ventricles prevent backflow
- Semilunar valves (pulmonic and aortic) regulate exit from RV and LV
- As blood fills atrium, pressure opens valve, blood flows into ventricle (fluid accumulationg pushes down toward AV valves, downward pressure opens up blood flwo to ventricles)
- Ventricle filled with blood–>pressure prevents PULMONIC/AORTIC valve from opening, those need to stay close when ventricle filling up, want iblood to leave LV and RV with a huge force, blood has to travel a huge distance, so has to be deliberatly forced out and pumped through ventricles, do not want blood drip dripping into ventricle and then dripping into aorta, will not have hte force to make it through the system–> what this means is semilunar valves are closed until forceful contraction from ventricles, action potentials get all the way to apex and purinkin fibers hte electrical prt of all of this, then those P. fibers cause ventricles to contrat then vencticle systole, THAT FORCES semilunar valves open so blood will go out in forceful way from ventricles what youw ant**** with big action potential energy behind it*
- Efficient pumping allows a higher body temperature and faster metabolism
heart 2
- right atrieum, to right ventrical, to pulmonary artery, to the lungs to pick up oxygen /oxygenated, then back through pulmonary veins, left atrium then left ventrical, then out through aorta* largest artery and other arteries from there
valves
obviously very important to stop backflow of lblood RA and right ventrical= tricupsid valve La and LV= bicupsid valve, also called mitral valve both atrioventricular valves, meaning between atrial and ventrical, close when ventricles are contracting so dont get blood going back up
gap junctions in heart
gap junctions in between cells that make up walls of heart
Semilunar valves
• Semilunar valves (pulmonic and aortic) regulate exit from RV and LV
- pulmonic valve right where blood leaves RV and goes to lungs
- aortic valve right where blood leaves LV and goes into aorta and rest of body
- pulmonic and pulmonary all means lungs*
Tricuspid valve
Tricuspid valve is between RA and RV
pulmonary circuit
when blood goes to lungs and back, and when blood goes out to aorta and all the way around the body through vena cava to right side of the heart is systemtic circulation, which is really most of our body
Bicuspid valve
Bicuspid valve (mitral) is between LA and LV
pulmonary artery
- carries deoxygenated blood, only artery in body that carries deoxygenated blood****
- artery because carrying blood away from the heart, carrying it to the lungs* that is why it is called the pulmonary ARTERY even though carrying less oxygenated blood–> goes to lungs–> more gas exchange occurs, blood gets oxygenated and comes back to the heart*
veins 2
carry deoxyganted blood, returning to heart to pick up oxygen again, but pulmonary veins which are bringing blood back to lungs are carrying oxygened blood* most veins in body are carrying blood already dropped off oxygen and going back to heart, only pulmonary veins are oxygenegated
major arteries and veins
- Aorta is a major artery, carries blood from LV
- Aorta splits into smaller arteries
- Veins from lower regions fuse into the inferior vena cava → RA
- Veins from upper regions fuse into the superior vena cava → RA
- Carotid artery → brain → jugular vein
- Subclavian artery → shoulders → subclavian vein
- Coronary artery → heart → coronary vein, circles around outside of heart because the muscles making up walls of heart need to be nurished by own supply of oxygenated blood, not nurished by blood pumped by heart* need own**
- Renal artery → kidney → renal vein
Carotid artery
Carotid artery → brain → jugular vein
after blood leaves these arteries
jugular vein, subclavian vein, coronary vein, renal vein
veins from lower regions… veins from upper regions….
- Veins from lower regions fuse into the inferior vena cava → RA
- Veins from upper regions fuse into the superior vena cava → RA both vena cavas are last vessels before heart itself*
difference btw fetuses and us
DIFFERENCE= blood not oxygenated at lungs, oxygenated from placenta, getting oxygen from mom’s circulatory system coming across the placenta*** so blood doesn’t have to go to lungs to pick up oxygen, so lung tissue during development is light paper consistency, good to have not much blood flow to the fetal lung because tissue is so fragile*** blood pressure would be the thing that would cause damage to tissue because tissue is so delicate, dont want ot turn a big hose on something not very strong* main differences in fetal circulation is avoiding too much blood flow to lung**
fetal hearts and circulation
hole btw aetrea called –> In fetal heart, foramen ovale is a hole in interatrial septum
- Foramen ovale lets blood flow RA → LA MEANS DOESNT GO TO LUNGS if goes straight from RA to LEFT A****
- Foramen ovale diverts blood from nonfunctional lungs
- In adults, fossa ovalis is the sealed region that covers the previous foramen ovale
- In fetus, ductus arteriosus diverts blood from pulmonary artery to aorta (bypasses lungs) another diversion, puts blood from pulmonary artery to aorta, on its way to the lung and shunted over to aorta again skipping the lungs** and skipping whole left side of heart**
- In fetus, ductus venosus receives blood flow from umbilical vein (bypasses liver)** liver fragile so needs some blood but not a full gush of blood
- Fetus gets blood from umbilical vein, gives wastes through umbilical artery umbilical vein how fetus gets its oxygenated blood** what brings the blood right into fetuses blood through placenta and then waste goes out through umbilical artery*
- materials defuse acrosse placenta, maternal blood and fetal blood do not mix together like do not go into one space and mix together, placenta has interphase fetal blood on one side and maternal in anohter, active rtansport/diffusion, from mother’s side O2 and nutrients fo from matenral blood to kid, Co2. Umbellical vein comes in and rejoins circulatory system, and then goes out with umbilical artery, goes all around fetuses body fetal heart is just service as a pump role of oxygantatin is just carried out in a completely separate location. All you need to know is blood reeners circulaiton eventualy makes its way to fetal heart
fetus circulation 2
- In fetal heart, foramen ovale is a hole in interatrial septum
- Foramen ovale lets blood flow RA → LA
- Foramen ovale diverts blood from nonfunctional lungs
- In adults, fossa ovalis is the sealed region that covers the previous foramen ovale
-but NOT ALL THE blood goes into that whole, so you can go into the RV to get into pulmonary artery, not all hte blood but some
fetus circulation 3
- In fetus, ductus arteriosus diverts blood from pulmonary artery to aorta (bypasses lungs)
- In fetus, ductus venosus receives blood flow from umbilical vein (bypasses liver) a detour around the liver, doesn’t mean that no blood goes to the liver just less goes to liver* instead of fill flow of vessels just a tiny little thing fluid able to spread out and lower hte pressure, one alternate route available during fetal development so less blood pressure expereinced by liver becuas eblood tissue is so fragile, still need some flow but little detour to get rid of hte pressure/damage*
- Fetus gets blood from umbilical vein, gives wastes through umbilical artery
electrical signaling 2
AV node, where signal delayed for a second= gives ventricals a chance to fully fill up then signal passes down towards bundle branches, the electrical signal action potental, action potental, other name for bundle branches are bundle of hiss, good to know both terms signal passes all the way down to apex of heart at bottom, comes back up around through Purkinje fibers 4. around ventricles, causes ventricles to contract, gets you ventricular sysole* the big squeezing
ECG
under numbr 2 where you have artrea contracting* memorize that what you are seeing on ECG is called a P wave*** little hill mostly yellowish, that is the p wave for atriole systole* look at number 4 when ventricles are contracting most forceful part of heart cycle, ventricles have to work really really hard out of aorta, spiky part on ECG called QRS complex***
blood pressure measurements
• Two blood pressure measurements: systole/diastole (normal ~ 120/80) 120- systolic pressure 80-diastolic pressure systolic pressure in arteries when heart is contracting during systole, the maximum pressure because heart contracting is shoving blood out into arteries, when heart is relaxing that is when what you are measuring is diastolic pressure
blood pressure in arteries and veins
- Blood pressure is highest in arteries, lower in veins
- Blood pressure decreases as blood moves away from heart (can be zero far from heart) AS MOVE AWAY FROM HEART PRESSURE DROPS* make sense heart beat, ventricles contracting is what pushes blood out of heart, as blood gets further away from that blood pressure goes down* goes all the way down to capillaries then back to veins, blood pressure really low which is why skeletal muscles getting up and moving around helps keep blood flowing through veins, veins have valves which helps back flow of blood
- Because blood pressure is low, veins have valves to prevent back flow against gravity if for some reason lose a lot of blood blood pressure drops, goes into circulatory shock, can also faint if not enough blood flow to brain
blood pressure in arteries and veins 2
- During locomotion, muscles squeeze veins and help peripheral circulation
- With no locomotion, blood can pool in veins
- Blood plasma forced out through capillaries, can lose significant volume
- Low blood flow to brain → fainting
- Acute circulation loss → circulatory shock (loss of consciousness, tissue damage, death)
- Blood pressure is regulated by vasoconstriction and vasodilation
hydrostatic and osmotic pressure in capillaries
outward flow, watery part of blood not big cells or proteins, but a lot of plasma flowing out, fluid leaves capillary goes out and baves the tissues, means flows to the tissues so net outward flow of fluid from capillary* and then there is still an osmotic pressure, meaning still solute in blood still have albumin osmoregularoty proteins they do not leave, but at beginning of capillary hydrostatic pressure out is greater than osmotic pressure that would draw fluid back in hydrostatic prssure OUT > osmotic presure in Right side of picture flips= after fluid left capillary, osmotic pressure sucks fluid back in all this solute still in blood, inward draw now by osmoatic pressure to bring fluid back in, now osmotic pressure in is greater than hydrostatic pressure out so inward flow of fluid back into capillary****
Hydrostatic and osmotic pressure 4
- Across a capillary bed, there is a net flow of plasma out of capillaries
- Hydrostatic pressure drops across the capillary bed, but osmotic pressure is constant
- At arteriole-proximal end, hydrostatic pressure OUT > osmotic pressure IN
- Fluid flows out to interstitial space
- At venous-proximal end, hydrostatic pressure OUT < osmotic pressure IN
- Fluid flows into capillaries
- Volume out exceeds volume in
- Net flow plasma fluid (~10%) into interstitial fluid
- Lymphatic system recovers plasma fluid and returns it to circulation
At arteriole-proximal end
• At arteriole-proximal end, hydrostatic pressure OUT > osmotic pressure IN
At venous-proximal end,
• At venous-proximal end, hydrostatic pressure OUT < osmotic pressure IN
Blood Pressure 2
- Blood pressure results from hydrostatic + osmotic pressure
- Hydrostatic pressure = fluid pressure on blood vessel walls (cardiac output and vascular resistance)
- Increase in cardiac output → blood pressure increases
- Decrease in cardiac output → blood pressure decreases
Blood Pressure 3
- Vasoconstriction → vascular resistance increases (less x-sectional area) and bp increases
- Vasodilation → vascular resistance decreases and bp decreases
- Blood pressure regulated by renin → aldosterone secretion
- Two blood pressure measurements: systole/diastole (normal ~ 120/80)
- Systole = heart contraction
- Diastole = heart relaxation
- High blood pressure = hypertension
- In hypertension, heart has to work harder, can cause heart degeneration
heart cycle 2
- Two circuits for blood flow: pulmonary and systemic
- Pulmonary circuit is between heart and lungs
- Systemic circuit is between heart and rest of body
- Blood returns from tissues into the RA
- RA pumps blood into RV
- RV pumps blood into pulmonary arteries
- Pulmonary arteries feed into lung capillary beds, enabling CO2 release and O2 uptake
heart cycle 3
- Blood enters pulmonary veins
- Pulmonary veins return blood to LA
- LA pumps blood into LV
- LV pumps blood into the aorta and systemic circuit
- Aorta splits into several arteries, carrying oxygenated blood (high O2, low CO2) to tissues
- Blood returns from tissues into RA (low O2, high CO2)
- Pulmonary arteries are only arteries with deoxygenated blood (most O2-depleted in body)
- Pulmonary veins are only veins with oxygenated blood (most O2-enriched in body)
pacemaker and heart contractions
- Heart contracts spontaneously via its own electrical signals, gap junctions
- Electrical signal is initiated at sinoatrial (SA) node
- Signal travels from SA node to atrioventricular (AV) node
- Bundles of His, then Purkinje fibers spread conduction through ventricles
- Atria contact first
- After a delay, ventricles contract
- Normal resting heartbeat ~70 bpm
- Double “lub-dub” heart sound is from closing valves (atrial, then venticular)
- Defects in valves causes heart murmur
- Autonomic nervous system can speed or slow contraction
- Sympathetic increases heart rate, parasympathetic decreases heart rate
- Receptors for adrenaline in heart are β-adrenergic receptors
- Beta-blocker drugs decrease heart activity, blood pressure
diastole
in cardiac cycle, period of relaxation of the heart muscle accompanied by the filling of the chmabres with blood
diastole is followed in the cardiac cycle by contraction or systeole of the heart muscle
it is when the muscle relaxes! When the muscle relaxes, the heart chamber fills with blood, and a person’s blood pressure decreases*
diastole and systole image of heart filling with blood
The main purpose of the heart is to pump blood through the body; it does so in a repeating sequence called the cardiac cycle. The cardiac cycle is the coordination of the filling and emptying of the heart of blood by electrical signals that cause the heart muscles to contract and relax. The human heart beats over 100,000 times per day. In each cardiac cycle, the heart contracts (systole), pushing out the blood and pumping it through the body; this is followed by a relaxation phase (diastole), where the heart fills with blood, as illustrated in Figure 1. The atria contract at the same time, forcing blood through the atrioventricular valves into the ventricles. Closing of the atrioventricular valves produces a monosyllabic “lup” sound. Following a brief delay, the ventricles contract at the same time forcing blood through the semilunar valves into the aorta and the artery transporting blood to the lungs (via the pulmonary artery). Closing of the semilunar valves produces a monosyllabic “dup” sound.
so what vaso dilation and vaso constriction mean for blood…..
arterioles covered with smooth muscle, when smooth muscle is very relaxed get vaso dilation
constricted- bring diameter and radius of vessel down when constricted! like cardboard tube versus stray! when relaxed call it vasodilation, when it is constricted call it vasoconstriction! the reason we want to make this distinction that when you have vasodilation what that means for the blood is that you would have very low resistance** can flow through with very low resistance, adn with vasoconstriction can see why have high resistance! so we owe a lot of this udnerstanding to Dr. Poiseuille
resistance in a tube….
means its harder because resistance is 16 X greater when 2 cm goes to 1 cm, just dropped the radius a tiny bit and resistance went up 16 X !! and that is why its so hard, so then can apply this to blood vessels!!
ex of cross sectional area (like a physics problem)
Q. 7 Which of hte following would tend to promote filtration from a capillary bed into the surrounding interstitium?
a. a dec in arterial blood pressure
b. a decrease in protein cocnetnration in blood
c. a decrease in interstitial osmotic pressure
d. an increase in interstitial hydrostatic pressure
b. a decrease in poretein cocnentation in blood
as we go left to right in this picture, talkign about a capillary pressure that would flow out* first part that says otuward flow, then inward flow is fluid coming back into the capillary** so to bakc up for a second the reason you need fluid leaving the capillary this is the poitn where all this with O and nutrients can get out and bathe the cell* that upper part of picture not even shown would be cells of the body* those arrows pointign upward reflect fluid going out delivering glucose plus oxygen to teh cell, capillary inward flow coming back into the capillary that fluid then comes in containign carbon dioxie and waste*
only at the level of the capillaries that you actually have exchange at hte level of tissues of body, where real action is all the thing circulatory system is transportign have ot get to cells* this is where and how it happens* blood pressure here represents hydrostatic pressure adn that is basically the pressure that comes from volume of blood, cardiac output pretty far from heart at this poitn but still teh force from teh heart is driving blood forward, osmotic pressure is basically the pressure caused by osmosis and that is the drive for water to go where th solute is* that is the main thing that is bringing hte fluid back into teh capillary after it has had a chance to deliver stuff to muscle cells and other stuff otuside of capillary it is really the solute inside the blood, things like big proteins big contributor, albium what sucks water and fluid with everything dissovled in it into teh capilary*
Q. 7 Which of hte following would tend to promote filtration from a capillary bed into the surrounding interstitium?
a. a dec in arterial blood pressure
b. a decrease in protein cocnetnration in blood
c. a decrease in interstitial osmotic pressure
d. an increase in interstitial hydrostatic pressure
b. a decrease in protein cocnetnration in blood
so what would make arrow on left hand side biger or less movement back in the right arrow smaller, in either of thsoe cases end up with more fluid on outside of insteritium*
we are looking for what will give us more fluid stuck on the outside, a decrease in arteriole blood pressure, that would really be making this first arrow the hydrostatic arrow smaller* because hydrostatic is from the bulk fluid pressure of the blood coming from the arteries* that arrow would be smaller, how can cross out answer choice *
b- says a dec in protein concentration in the blood, so now really thinking about arrow on righthand side, really like proteins in the blood that are pullin g the water, water wants to follow where all the solute is, so what would happen if you had fewer proteins in teh blood, if you got rid of some of those proteins the arrow would get smaller* if tha arrow gets smaler you would have more fluid NOT coming back in** more fluid staying outside of the capillary*** which is what we wnat to find*
c- osmotic pressure is always constant under normal circumstances, if under some reason it got much smaller that would facilitate fluid mlving into teh capillary becuase there would be less of an undertoe backwards* if the interstital osmotic pressure decreased*
d- if there was a whole bynchg of extra water that would push back against black arrow in opposite direction from a lot of fluid built up in interstitium, tht would hold fluid mroe in capillary and prevent it from goign out in teh same way*
if there were more hydratic pressure in interstitium the arrow out would force more resistance–> less fluid woud leave the capillary, bigger there is the more the fluid goes out, if heading into more resistance heading into a headwind then less fluid would leave th capillary*
Q7. Which of the following would tend to promote filtration from a capillary bed into the surrounding interstitium?
a. a decrease in arterial blood pressure
b. a decrease in protein concentration in blood
c. a decrease in interstitial osmotic pressure
d. an increase in interstitial hydrostatic pressure
Answer- b. a decrease in protein concentration in blood
so c. osmotic pressure is constant “Hydrostatic pressure drops across the capillary bed, but osmotic pressure is constant” from outline
and remember filtration means things leaving adn not coming back in, net movement out*
if there were more hydratic pressure in interstitium the arrow out would force more resistance–> less fluid woud leave the capillary, bigger there is the more the fluid goes out, if heading into more resistance heading into a headwind then less fluid would leave th capillary*
Q16. If a patien’s heart beats approximately 500 times in 5 minutes, and the stroke volume is 80 ml, what is the correct value for cardiac output?
cardiac output= 8 L/min
think of troke as beat of the heart, so it is volume per squeeze
Q23. All of the followign statements about blood pressure are true except:
a. bp is lower in teh vena cava than in teh aorta
b. aldosterone antagonist will counteract the effect of a high salt diet on blood pressure
c. high salt diets are likely to lead to hypertension
d. hydrostatic pressure is constant across a capillary bed
no hydrostatic pressure goes dwon down down, beucase hydrostatic pressure is related to volume, as fluid is leving the capillary there is lower volume in teh capillary*
osmotic presure is the one that is constant*
answer= d. hydrostatic pressure is constant across a capillary bed- no osmotic pressure is constant, hydrostatic pressure changes!
Amanda notes 12/6
What Happens in Patent Ductus Arteriosus?
The ductus arteriosus is a normal blood vessel that connects two major arteries — the aorta and the pulmonary artery — that carry blood away from the heart.
The lungs are not used while a fetus is in the womb because the baby gets oxygen directly from the mother’s placenta. The ductus arteriosus carries blood away from the lungs and sends it directly to the body. When a newborn breathes and begins to use the lungs, the ductus is no longer needed and usually closes by itself during the first 2 days after birth.
If the ductus doesn’t close, the result is a patent (meaning “open”) ductus arteriosus. The PDA lets oxygen-rich blood (blood high in oxygen) from the aorta mix with oxygen-poor blood (blood low in oxygen) in the pulmonary artery. As a result, too much blood flows into the lungs, which puts a strain on the heart and increases blood pressure in the pulmonary arteries.
In infants born with other heart problems that decrease blood flow from the heart to the lungs or decrease the flow of oxygen-rich blood to the body, the PDA may actually help, and the doctor might prescribe medicine to keep the ductus arteriosus open.
ductus arteriosus 2
Fetus circulation 4
Fetal circulation is different to the circulation of a newborn baby and an adult. In the fetus, not much blood passes through the lungs. The fetus is not breathing air and the lungs are filled with fluids. Rather, it receives oxygen-rich blood from the placenta via the umbilical cord.
In fetal circulation, the placenta mainly supplies blood to the left atrium, through an anatomical opening called the foramen ovale.
Aside for the patent foramen ovale, there is another important connection, the patent ductus arteriosus, the connection between the pulmonary artery and the aorta, allowing blood to travel through the pulmonary artery to bypass the lungs and go straight into the aorta. Blood can bypass the lungs because of high vascular resistance in the pulmonary arteries, allowing the blood to more easily flow into the aorta.
In the fetus, oxygenated blood flows through the umbilical vein to the liver and passes through the ductus venosus before joining with the inferior vena cava. The blood will enter the right atrium and then either go into the right ventricle or it will go through the patent foramen ovale into the left atrium, before being pumped in the left ventricle and into the (ascending) aorta.
The blood that is pumped from the right ventricle can go through the pulmonary artery to enter the lungs, but mainly bypasses the lungs straight into the (descending) aorta via the patent ductus arteriosus. Through the aorta, blood flows into the fetal body and back to the placenta via the umbilical arteries.
3 Shunts in Fetal heart (fetal circulation 5)
Through the blood vessels in the umbilical cord, the fetus gets all needed nutrition and oxygen. The fetus gets life support from the mother through the placenta.
Waste products and carbon dioxide from the fetus are sent back through the umbilical cord and placenta to the mother’s circulation to be removed.
The fetal circulatory system uses 3 shunts. These are small passages that direct blood that needs to be oxygenated. The purpose of these shunts is to bypass the lungs and liver. That’s because these organs will not work fully until after birth. The shunt that bypasses the lungs is called the foramen ovale. This shunt moves blood from the right atrium of the heart to the left atrium. The ductus arteriosus moves blood from the pulmonary artery to the aorta.
Oxygen and nutrients from the mother’s blood are sent across the placenta to the fetus. The enriched blood flows through the umbilical cord to the liver and splits into 3 branches. The blood then reaches the inferior vena cava. This is a major vein connected to the heart. Most of this blood is sent through the ductus venosus. This is also a shunt that lets highly oxygenated blood bypass the liver to the inferior vena cava and then to the right atrium of the heart. A small amount of this blood goes straight to the liver to give it the oxygen and nutrients it needs.
Waste products from the fetal blood are transferred back across the placenta to the mother’s blood.
The fetal heart
Blood enters the right atrium. This is the chamber on the upper right side of the heart. When the blood enters the right atrium, most of it flows through the foramen ovale into the left atrium.
Blood then passes into the left ventricle. This is the lower chamber of the heart. Blood then passes to the aorta. This is the large artery coming from the heart.
From the aorta, blood is sent to the heart muscle itself and to the brain and arms. After circulating there, the blood returns to the right atrium of the heart through the superior vena cava. Very little of this less oxygenated blood mixes with the oxygenated blood. Instead of going back through the foramen ovale, it goes into the right ventricle.
This less oxygenated blood is pumped from the right ventricle into the pulmonary artery. A small amount of the blood continues on to the lungs. Most of this blood is shunted through the ductus arteriosus to the descending aorta. This blood then enters the umbilical arteries and flows into the placenta. In the placenta, carbon dioxide and waste products are released into the mother’s circulatory system. Oxygen and nutrients from the mother’s blood are released into the fetus’ blood.
At birth, the umbilical cord is clamped and the baby no longer gets oxygen and nutrients from the mother. With the first breaths of life, the lungs start to expand. As the lungs expand, the alveoli in the lungs are cleared of fluid. An increase in the baby’s blood pressure and a major reduction in the pulmonary pressures reduce the need for the ductus arteriosus to shunt blood. These changes help the shunt close. These changes raise the pressure in the left atrium of the heart. They also lower the pressure in the right atrium. The shift in pressure stimulates the foramen ovale to close.
Blood circulation after birth
The closure of the ductus arteriosus, ductus venosus, and foramen ovale completes the change of fetal circulation to newborn circulation.
