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28 Cards in this Set
- Front
- Back
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what is the relationship between the cardiovascular system and blood vessels?
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blood vessels transport blood throughout the body and makes up the cardiovascular system.
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what is the relationship between the heart, arteries, veins, arterioles, capillaries, and venules?
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the heart pumps the blood.
the arteries transport blood away from the heart to the rest of the body. the veins transport blood to the heart to be oxygenated. capillaries are smaller vessels where gas exchange between blood and interstitial fluid happens. venules collect blood from the capillaries arterioles are the smallest branches of arteries. |
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What is the structure of a blood vessel wall?
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Tunica intima-thin innermost layer. endothelia cells.
Tunica media-middle layer. made of muscle cells. muscle activity influences vessel diameter and blood flow. Tunia externa-outermost layer. made up of connective tissue. anchors vessel into surrounding tissue. |
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Arteries VS veins
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arteries have a rounder lumen with thicker walls. also more elastic.
veins have a flater, thinner lumen. have valves. |
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What properties are assosciated with arteries? why are they meaningful?
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Elasticity. Absorbs pressure waves with each heartbeat.
Contractility. Changes in diameter depending on vasodilation and vasoconstriction. affects afterload on heart, peripheral blood pressure and capillary blood flow. |
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How are arteries categorized?
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1. Elastic Arteries-Large. Less muscle cells and more elastic fibers.
2. Muscular Arteries-Medium. More muscle cells. 3. Arterioles-Small. no tunica externa. very little tunica media. |
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How are capillaries organized?
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1.Continuous capillaries. found in all tissues except epithelia and cartilage. complete endothelial lining. permit exchange of water and solutes. restrictive permeability due to blood brain barrier. specialized continuous capillaries found in CNS and thymus.
2. Fenestrated capillaries. have pores. permits exchange between water and larger solutes. found in choroid plexus, kidneys, endocrine organs, intestinal tract. 3. SInusoids. Have gap juntions between endothelia cells. permit exchange between water and large solutes. found in liver, spleen, bone marrow, and some endocrine organs. |
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What is the structure of a capillary bed?
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Arterioles-> Capillaries->drains into venules.
precapillary sphincters control bloodflow. collaterals-more than one artery supplying a capillary bed. aterial anastomosis- joining of blood vessels. protects capillary bed because if one artery becomes blocked then the other will supply the capillary bed. |
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how is blood flow regulated in a capillary bed?
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Vasomotion. cycling of contraction and relaxation of capillary sphincters. Causes blood flow in capillaries to constantly change routes. controlled by changes in interstitial fluid (O2&CO2)
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how are veins categorized?
(veins have lower blood pressure than arteries) |
1. Venous Veins. valves. to prevent backflow. compression from muscle activity pushes blood toward heart.
2.Venules. very small. collect blood from the capillary bed. 3.Large veins. have all three tunicas. thick tunica externa. 4.medium sized veins. thin tunica media and few muscle cells. tunica externa is thickest layer with longitudinal bundles of elastic fiber. |
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Under normal functional conditions, how is blood distributed throughout the blood vessels?
How is blood redistributed following severe blood loss? |
Venous system holds 64% of blood
Pulmonary circuit 9% Heart 7% Systemic arterial system 13% systemic capillaries 7% Vasomotor center in medulla oblongata stimulates sympathetic nerves innervating smooth muscle. 1. Venoconstriction. systemic veins constrict and venous system moves blood into the arterial system. 2. Veins constrict and redistribute venous reserve, -blood flow to brain and other delicate organs can be maintained even after substantial blood loss. |
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What is the relationship between blood pressure, resistance, and blood flow?
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Blood flow is determined by resistance and blood pressure. F a (change in)P. F a 1/R.
Pressure gradient is more important than absolute value. |
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What are typical values for blood pressure within the arterial system, along capillaries, and within the venous system?
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1. Blood Pressure. arterial pressure is 100 mm hg at aorta to 35 mm hg at the beginning of a capillary.
2. Capillary Hydrostatic Pressure (CHP). is the force of blood exerted on a capillary wall. 35mm hg-18mmhg. 3. Venous Pressure.18mm hg -2mm hg |
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What factors contribute to total peripheral resistance?
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changes in blood pressure in the systemic circuit must overcome total peripheral resistance in order for circulation to occur.
Vascular resistance. ex: friction. depends on vessel diameter. larger diameter, less friction and less resistance. Viscosity. suspended materials in a liquid. Turbulence. swirling of blood. |
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As vessels transition from arteries to capillaries to veins,
o how does vessel diameter change? o how does total cross-sectional area change? o how does pressure change? o how does the velocity of blood flow change? |
1. vessel diameter diverges and becomes smaller. then converge and become larger.
2. total cross sectional area increases. then decreases. (affects blood pressure) pressure changes as cross sectional area increases, 3. blood pressure decreases (due to resistance). Venous pressure remains low. 4. velocity changes as cross sectional area increases, velocity decreases. as cross sectional area decreases, velocity is driven up. |
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What is the relationship between systolic pressure, diastolic pressure and pulse pressure?
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Systolic pressure- peak aterial pressure.
Diastolic pressure-minimum arterial pressure. Pulse pressure- difference between systolic pressure and diastolic pressure. (SP-DP=PP) |
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How do you calculate mean arterial pressure?
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MAP=DP+1/3PP
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How does elastic rebound influence blood flow?
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Arterial walls stretch during systole and recoil during diastole. keeps blood flowing during diastole.
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What other body systems help facilitate venous return?
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muscular compression. respiratory pump causes thoracic cavity to change pressure.
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What are the 3 main processes of capillary exchange?
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Diffusion. Filtration. Reabsorption.
1. diffusion of ions and molecules move from high to low concentrations. Water, ions, large solutes, lipids and lipid soluble O2 and CO2, plasma proteins. 2. Filtration. movement of fluid across a membrane. pores restrict certain solutes based on size. capillary filtration water and small solutes are forced across capillary wall. 3. Re absorption. Return of fluids into the blood stream. result of osmotic pressure- force of osmotic water movement. Blood colloid osmotic pressure- caused by suspended blood proteins that are too large to cross capillary walls. |
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Capillary exchange
What is the relationship between filtration, reabsorption, net capillary hydrostatic pressure, net capillary colloid osmotic pressure, and net filtration pressure? Do capillaries perform more filtration or more reabsorption? |
during filtration, water and solutes move OUT of the capillary and into interstitial fluid.
during reabsorption, water and solutes move INTO bloodstream. -ensures constant communication and mutual exchange. -accelerates distribution of gases and nutritents and water throughout tissues. -flushes bacteria and toxins into lymphatic system. |
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can tissue perfusion be regulated?
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through
1.peripheral resistance 2. blood pressure 3. cardiac output |
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How does auto-regulation of blood flow in tissues occur?
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homeostasis is disturbed by stress, chemical changes, or increased tissue activity->inadequate local blood pressure and blood flow to tissues->local vasodilators are released->decrease in resistance&increase in blood flow-> homeostasis restored.
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How does the nervous system regulate blood pressure and flow?
Which regulatory centers of the medulla oblongata are involved? How do baroreceptor reflexes function? How do chemoreceptor reflexes function? |
cardiovascular centers of the medulla oblongata regulate cardiac output by cardioaccelelatory and cardioinhibitory centers.
-baroreceptor. responds to changes in pressure. when pressure rises, CV centers decrease cardiac output and vasodilation occurs. When blood pressure falls, CV centers increase cardiac output and causes peripheral vasoconstriction. -chemoreceptor. responds to chemical changes. changes in carotid bodies and aortic bodies. 1. causes respiratory rate to increase and return to homeostasis. 2. cardioacceleratory centers stimulated and increased cardiac output. vasoconstriction occurs. |
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How does the endocrine system regulate blood pressure and flow?
What are the effects of epinephrine, norepinephrine, antidiuretic hormone, angiotensin II, aldosterone, erythropoietin, and natriuretic peptides? |
-Hormones released by endocrine glands can increase cardiac output and vasoconstriction. Ex: Epinephrine and Norepinephrine
-ADH is released in response to low blood volume. works to retain water by kidneys to raise blood pressure and peripheral vasoconstriction. -Antiotensin II is released in response to fall in renal blood pressure. causes thirst. -aldosterone promotes Na+ retention in kidneys -erythropoietin. stimulates red blood cell production. released by kidneys in response to low blood pressure, or O2. -Natriuretic peptides. increases Na+ secretion in kidneys. Water loss through urination. Reduce thirst. stimulates vasodilation. Blocks ADH, aldosterone, E, NE. |
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How does cardiovascular system function change during light exercise? heavy exercise?
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extensive light exercise, increases cardiac output, vasodilation, and increased venous return.
heavy exercise increases cardiac output to a maximum. restricts bloodflow to nonessential organs for adequate supply of blood to lungs, heart, and skeletal muscle. |
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How does the cardiovascular system respond to hemorrhaging?
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Short term elevation of blood pressure. peripheral vasoconstriction and increased heart rate to maintain cardiac output.
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What age-related changes occur within the cardiovascular system?
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Blood. valve deterioration causes pooling of blood in legs. decreased hemocrit, perihperal blockage by bloodclot.
Heart. Reduced maximu cardiac output. reduced circulation. reduced elasticity. accumulation of scar tissue. Blood Vessels. |
