Term
| Name the five general types of blood vessels in the cardiovascular system. |
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Definition
| arteries, arterioles, capillaries, venules, veins |
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Term
| Describe the general differences between systemic and pulmonary circulation. |
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Definition
pulmonary- arteries carry o2 poor blood and veins carry o2 rich blood from lungs to heart.
system- arteries always carry o2 blood and veins carry o2 poor blood |
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Term
| Name the innermost to outermost 3 distinct tissue layers of blood vessels walls. |
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Definition
| tunica interna/intima, tunica media, tunica adventitia |
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Term
| Describe the general composition of each of the tissue layers named above. |
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Definition
tunica interna- endothelium (simple sqaumous ET) also has subendothelial level
tunica media- elastic fibers and sheets of smooth muscle
tunica adventitia- collagen (thin layer) |
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Term
| Describe the general structure and function of simple squamous CT, dense fibrous CT, elastic CT, areolar CT, smooth muscle. |
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Definition
simple squamous CT- scale like; diffusion and secretion
dense fibrous CT- strong rope like collagen; in tendon and ligaments
elastic CT- very stretchy skin, lungs, arteries, veins, connective tissue proper, elastic cartilage, periodontal ligament, fetal tissue and other structures.
areolar CT- looks like fiberglass; loose packing , support, and nourishment
smooth muscle- smooth, can tense and relax, controls size of lumen of arterioles-arteries |
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Term
| Which layer of the blood vessel wall is continuous with the endocardium of heart? |
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Definition
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Term
| What effect does the sympathetic nervous system have on vascular smooth muscle tone? |
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Definition
Sympathetic division is responsible for maintaining vasomotor tone (constant level of nervous stimulation of muscle walls)
-when activated, vasodilation occurs and lumen diameter increases
-decreases contraction --vasoconstriction and reduces size of lumen diameter (contract) |
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Term
| Identify the three basic types of arterial vessels and describe the structural and functional differences between them. |
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Definition
elastic arteries (conducting arteries)- largest and most elastic, function as a pressure reservoir.
muscular arteries (distributing arteries)- thick tunica media, very muscular, distribute blood to specific body organs
aterioles- very small (some larger ones have all tunic layers and usually tunica media is very muscular with little elastic fiber) conduct blood from arteries to capillaries. |
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Term
| Which arterial vessels serve as a pressure reservoir between contractions of the ventricles? |
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Definition
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Term
| Which arterial vessels help to distribute blood to specific body organs or regions of the body? |
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Definition
| muscular arteries (distributing arteries) |
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Term
| Why are the arterioles called the resistance vessels of the vascular system? |
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Definition
| arterioles regulate the arterial blood pressure and blood flow into an organ. |
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Term
| Which arterial vessels play the most important role in regulating blood flow into capillary beds and in regulating blood pressure? |
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Definition
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Term
| Identify and describe the arterial vessel which directly supplies a capillary bed. |
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Definition
metarteriole- intermediate between arteriole and capillaries
or is it terminal arteriole? |
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Term
| What role do the precapillary sphincters play in regulating blood flow to the capillaries? |
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Definition
| precapillary sphincter surrounds the entry into each true capillary and acts as a valve to regulate blood flow into capillary. |
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Term
| What is the relationship between a metarteriole and a thoroughfare channel? |
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Definition
| metarteriole is continuous with thoroughfare channel |
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Term
| What is the relationship between the metabolic activity of a tissue and the number of capillaries it contains? |
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Definition
| More metabolic activity, larger number of capillaries. |
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Term
| Identify and describe the structure of the three types of capillaries. |
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Definition
continuous capillaries- endothelial cells form a continuous tube, has tight junctions but intercellular cleft which allows some fluid and solute out. in blood brain barrier, tight junction of brain is continuous
fenestrated capillaries- endothelial cells have pores, allows rapid exchange of water/small solutes between blood and interstitial fliud
sinusoid- large, irregularly shaped lumen and very leaky walls, allow passage of large molecules and blood cells, very slow blood passage |
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Term
| Identify and describe the structure of the major types of venous vessels. |
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Definition
venules- small, thin walled vessels, porous
veins- lumen is large but walls are thin, tunica media is thin, tunica externa is the thickest layer, walls are collapsed but can be stretched |
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Term
| Name the venules which directly drain capillary beds. |
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Definition
| Thoroughfare channel ( or is it postcapillary venule) |
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Term
| Which blood vessels serve as the blood reservoir? |
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Definition
| veins (65% of body's blood supply is found in veins) |
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Term
| Why are the veins considered the capacitance vessels of the cardiovascular system? |
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Definition
| because the veins are the site of where most of the blood is found and where regional blood volume is regulated |
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Term
| What is the purpose of valves in the veins? |
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Definition
| They prevent back flow of blood. |
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Term
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Definition
| The volume of blood flowing through a vessel, an organ, or an entire circulation in a given period (ml/min). |
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Term
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Definition
| Blood pressure is the force per unit area exerted on a vessel wall by contained blood, expressed in Hg. (refers to systemic arterial blood pressure in largest arteries near the heart) |
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Term
| Define peripheral resistance. |
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Definition
| The opposition to flow and is a measure of the amount of friction blood encounters as it passes through the vessels. Most friction occurs in systemic/peripheral circulation so its called peripheral resistance. |
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Term
| Describe blood viscosity, vessel length, vessel diameter. |
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Definition
blood viscosity-(constant) internal resistance to flow that exists in all fluids, blood's "stickiness". The greater the viscosity the less easy molecules can slide across each other.
vessel length- (constant) longer the vessel, the greater the resistance (blood pressure increases are you age because your blood vessels get longer)
blood vessel diameter-(frequent change)smaller the blood vessel the more fluid that comes in contact with the wall and less movement that can occur. Resistance varies inversely with the fourth power of the vessel radius.
-if radius of a vessel is doubled, resistance drops to 1/16 its original value. |
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Term
| What is delta P? How does delta P influence blood flow? |
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Definition
| Delta P is the difference in blood pressure between two points in circulation. When delta P increases, blood flow speeds up, and when delta P decreases, blood flow declines. Its inversely proportional to resistance. Resistance has a greater effect on blood. |
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Term
| Which blood vessels play the most important role in determining peripheral resistance? WHY? |
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Definition
| The small-diameter arterioles, which can enlarge or constrict in response to neural and chemical controls are the major determinant of peripheral resistance. Large arteries near the heart do not change dramatically in diameter and so do not contribute much to peripheral resistance. |
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Term
| Describe how pressure varies across the vascular system. Where is pressure highest? Lowest? |
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Definition
| Pressure is highest in the aorta, then arteries, then arterioles, then capillaries, then venules, veins and the venae cavae. highest- aorta, lowest- vena cavae. (because the nearer the fluid is to the pump the greater the pressure exerted on fluid) |
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Term
| How are blood flow, blood pressure and peripheral resistance related to each other? |
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Definition
blood flow (F)= delta P/ Resistance(R)
R is more important in influences blood flow than delta P |
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Term
| Define systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse pressure (PP). |
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Definition
systolic blood pressure- the pressure peak (120mm Hg) the end of systole, elastic arteries are strained, aortic valve opens
diastole blood pressure- end of diastole, elastic arteries are relaxing (80mmHg) aortic valve closes
pulse pressure- difference between the systolic and diastolic pressures, felt as a pulse during systole as elastic arteries are expanded by blood being forced into them by ventricular contraction |
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Term
| What adaptations enable blood to continue flowing through the veins toward the heart, in spite of the low blood pressure in the veins? |
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Definition
| respiratory pump skeletal muscle pump, layer of smooth muscle around veins that constrict under sympathetic control increasing venous return. |
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Term
| Define mean arterial pressure (MAP) and why is it important? |
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Definition
| MAP is the average blood pressure in an individual or pressure that propels the blood to the tissues. Its important because it tells us if the organs are getting enough blood. it is lower than 60 mmHg then the patient could be ischemic. |
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Term
| Given an SBP and DBP be able to calculate MAP. |
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Definition
MAP= diastolic pressure + (pulse pressure/3)
if 120/80
ex MAP= 80 + (40/3) 93mmHg |
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Term
| How do changes in cross sectional area affect the velocity of blood flow? At which level of the vascular tree is the velocity of blood flow lowest? |
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Definition
| Velocity and Cross sectional area are inversely proportional. The larger the cross sectional area, the slower the velocity. Capillaries have the largest cross sectional area and therefore the lowest blood flow velocity. (Aorto is smallest cross sectional, so highest velocity. |
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Term
| Identify the forces which help move materials into and/ or out of the capillaries. |
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Definition
| diffusion, filtration, osmosis |
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Term
| What passive transport process accounts for the exchange of dissolved gases and nutrients in the capillary beds? |
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Definition
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Term
| What processes account for the movement of fluid into and or out of capillaries? |
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Definition
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Term
| What are the specific factors that promote filtration in the capillaries? |
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Definition
| capillary hydrostatic pressure, interstitial fluid osmotic pressure |
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Term
| What are the specific factors that promote re absorption in the capillaries? |
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Definition
| blood colloid osmotic pressure, interstitial fluid hydrostatic pressure |
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Term
| What is the primary force that promotes fluid movement out of the capillaries? |
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Definition
| capillary hydrostatic pressure |
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Term
| What is the primary force that resists fluid movement out of the capillaries? |
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Definition
| blood colloid osmotic pressure |
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Term
| Identify the three factors which influence mean arterial pressure. |
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Definition
1) CO=HRxSV, enhanced CO increases MAP
2)Total Peripheral Resistance (TPR)- if TPR increases, MAP decreases
3)blood volume- if blood volume decreases then MAP decreases; but usually bv is constant through regulation and activities in kidneys |
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Term
| How are mean arterial pressure, cardiac output, and TPR related to each other? |
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Definition
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Term
| How do variations in heart rate and stroke volume influence mean arterial pressure? |
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Definition
CO=HRxSV
Since an increase of CO, increases MAP, then in increase in heart rate and stroke volume will also increase MAP. |
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Term
| Name and describe the location of the major components (ie sensory receptors, integration center, motor neurons, effector) of the reflex arcs which help regulate BP. |
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Definition
integration center (vasomotor center)- a cluster of neurons in the medualla that oversees changes in diameter of blood vessels effector
effector (vascular smooth muscle)-on organs
sensory receptor-baroceptor (in carotid sinus, aortic arch, and in large arteries of neck and thorax) or chemoreceptor, (aortic arch or large arteries in neck) |
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Term
| Describe the baroreceptor-initiated reflex for control of BP |
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Definition
When BP increases, it stretches baroreceptors, which send rapid impulse to vasomotor center. This inhibits vasomotor center, resulting in vasodilation of arterioles and veins, which decrease blood pressure.
If blood pressure is low, baroreceptors are inhibited, and sends impulse to stimulate cardioaccelatory center and stimulates vasomotor center. Then sympathetic impulse to heart goes up and heart rate, contractility, and CO all increase |
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Term
| What stimulus causes baroreceptor activity to increase? |
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Definition
| an increase in blood pressure---stretching of baroreceptor |
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Term
| What effect does increased baroreceptor activity have on the vasomotor center? on vascular smooth muscle? |
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Definition
| Increase baroreceptor activity inhibits vasomotor center and decreases contractility of vascular smooth muscle |
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Term
| Explain the effects on blood pressure of the following factors: catecholamines, ADH, renin angiotensin aldosterone system and atrial natriuretic peptide. |
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Definition
catecholamines-norepinephrine and epinephrine --enhance sympathetic fight or flight response, which vasoconstricts and increases BP (heart and arterioles)
ADH-increases blood pressure when blood pressure is extremely low, vasoconstriction in arterioles and kidney tubule cells
renin angiotensin aldosterone-when BP is low, renin is released and eventually angiotensis II stimulates intense vasoconstriction so blood pressure increases. Angiotensin II also releases aldosterone and ADH (long term regulation of blood volume increase)
Atrial natriuretic peptide- (produced by atria) causes blood volume and blood pressure to decrease, makes kidneys secrete more sodium and water from body and BV drops and vasodilation occurs. |
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