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17 Cards in this Set
- Front
- Back
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1) What factors affect stroke volume? What are some of the positive and negative factors. 2) What is the afterload? (review) s3 |
1) Intrinsic effect; increased venous return (preload of cardiac muscle cells) which increases filled EDV of ventricle, is an important factor controlling stroke volume. -If slow heartbeat, gives blood more time to fill and increased force, increased venous return. -Excercise can also increase venous return, increasing in sympathetic activities as veins are innervated and SV increases, more pumping action. -Blood loss and extremely rapid heartbeat decreases SV. 2) Pressure that ventricle needs to eject blood |
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1) What does the Frank-Starling Law of heart state? 2) What 3 factors (e.g. pumps) affect the venous return? s4 |
1) Stroke volume increases as EDV increases (increased with preload) 2)-Skeletal muscle pump that allow movement, important when going against going gravity esp. -Respiratory pump, allows us to breath and move blood to heart -Sympathetic innervation, brain sending sympathetic nerves and increase venous pressure |
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1) What factors affect the force of contraction? s4 |
1) -Stroke volume -Length of muscle fiber (affected by diastolic volume; the higher, the more you strech cardiac fibers, increase the number of cross bridges) and contractility of heart |
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1) What is a starling curve and what relationship does it show? What happens in a heart failure? exercise? s5,6 |
1) Stretch (indicated by ventricualr EDV mL) on X axis, Force (stroke volume, mL) on Y axis. As stretch increases, force increases; until reaches the optimal sarcomere length. After that its overstretched where force no longer increases. -In heart failure, can stretch but won't get as much force generation. -When exercising, sympathetic nervous system allows for more force generation. |
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1) What are the extrinsic factors that influence stroke volume? s7 |
1) Contractility (increase in contractile strength) is important, its independent of stretch and of EDV -> Increased sympathetic stimuli -> Certain hormones -> Ca2+ and some drugs (ionotropy strength) |
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Recap 1) Describe the chain of sympathetic neurons (NE) action in heart 1) Describe the chain of parasympathetic (Ach) neurons action in heart s9 |
1) β1-receptors of autorhythmic cells -> Increased Na+ and Ca2+ influx -> Increased depol -> increased heart rate 2) Muscarinic receptors of autorythmic cells -> Increased K+ influx and decreased Ca2+ influx -> hyperpol cell and decrease depol -> decrease heart cell |
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Recap 1) Describe the 2 mechanisms of Ca+ influx from epinephrine and NE, to give more cross bridge formation and more contraction. S10 |
1) -> Bind to B receptors, activate cAMP second messenger system, then activates PKA and increases open time of voltage gates calcium channels by phosphorylating them, have more Ca2+ coming in from ECF, more Ca2+ in SR -> PKA also phosphorylates Phospholamban, which is an inhibitor of the sarcoendoplasmic calcium ATPase (Sirca pump); [SIRCA responsible for collecting Ca from cell and storing them for next round] -> when phosphorylated, SIRCA not inhibited; it is pumping Ca2+ into SR, and increases Ca2+ conc there. |
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1) What is an inotropic agent? 2) Does sympathetic affect contractility or HR or both? Parasymp? s12,13 |
1) Any chemical that affects contractility
-> Epinephrine and NE are positive ones. -> B blockers and Ca2+ ch blockers are negative ones (useful when heart failure so heart doesnt become too stressed) 2) Both, just HR |
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1) What are the 3 types of blood vessels in the cardivascular system and what are the functions? s16 |
1) -Arteries (and arterioles): carry blood away from heart -Capillaries: Where nutrient and gas exchange occurs -Veins (and venules): Carry blood towards heart |
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1) what are the 3 groups of arteries? s17 |
1) -Elastic artery e.g. aorta, which gains elastic energy from heart
-Muscular artery: lots of smooth muscle at wall -Arterioles: Smallest, just ahead of capillaries. Points of regulation by sympathetic nervous system. Important control of blood entering tissue |
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1) Describe the structure of the blood vessel walls. s19 |
1) -Tunica intima: Very inside layer, endothelial cells. Thin square cells. -Tunica media: Smooth muscle and elastin found here. -Tunica externa: slightly thiner; Has fibroblast and collagen fibres |
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1) Describe the structure of veins vs arteries.
s20 |
1) They have valves as collection bags, arteries don't. Not much smooth muscle cells, more fibroblast cells and extracellular matrix. |
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1) Compare the pressure in artery, arteriole, capillary, venule, vein. 2) What is an important feature of the capillary 3) What is an important feature of arterioles? s21 |
1) artery > arteriole > capillary > venule > vein. 2) Only 1 layer, endothelium; easy diffusion. 3) They are muscular, give fine control of how much blood into tissue. |
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1) Describe the movement of blood from ventricles to the arterioles 2) Describe the importance of elastic recoil of arteries s23 |
1) Ventricle contracts -> semilunar valve opens -> aorta and arteries expand and store pressure in elastic walls -> arterioles 2) Once isovolumic ventricular relaxation happens, semilunar valve shuts, preventing flow back into ventricles. Elastic recoil of arteries sends blood forward into rest of circulatory system |
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1) What do veins/venules do and what are the important features s25 |
1) Drain blood from capillaries, much less smooth muscle and connective tissue than. arteries. Have valves preventing backflow. Carry about 70% of body's blood, act as reservoir during hemorrhage. |
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1) What are metarterioles s26 |
1) Sections of capillary beds, have metarterioles, are shut pathways allowing blood to avoid going through arterial beds. Important because they are pressure release valves. Capillaries lack smooth muscle and elastic tissue reinforcement, which facilitates exchange. |
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1) Capillary bed s28 |
1) Consists of two types of vessels. -> In a vascular shunt, metarteriole directly connets an arteriole to a venule -> True capillaries are exchange vessels; oxygen and nutrients cross to cells, carbon dioxide and metabolic waste products cross into blood |
