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A&P2 > Ch21 > Flashcards

Ch21 Flashcards

1
Q
  • Arteries – carry blood AWAY from the heart
  • Arterioles
  • Capillaries – site of exchange
  • Venules
  • Veins – carry blood TO the heart
A

blood vessel types

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2
Q
  • Inner lining in direct contact with blood
  • Endothelium continuous with endocardial lining of heart
  • Active role in vessel-related activities
A

tunica interna(intima) of blood vessel

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3
Q
  • Muscular and connective tissue layer
  • Greatest variation among vessel types
  • Smooth muscle regulates diameter of lumen
A

tunica media

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4
Q
  • Elastic and collagen fibers
  • Vasa vasorum
    • Capillaries that supply blood to tissues of the vessels
  • Helps anchor vessel to surrounding tissue
A

tunica externa

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5
Q
  • has 3 layers of a typical blood vessel
  • thick muscular to elastic tunica media
  • smooth muscle
    • provides for vasoconstriction-decrease in lumen diameter
    • vasodialtion- increase in lumen diam
A

arteries

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6
Q
  • Largest diameter artery but walls relatively thin
  • Function as pressure reservoir
  • Help propel blood forward while ventricles relaxing
  • Also known as conducting arteries
A

elastic arteries

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7
Q
  • Tunica media contains more smooth muscle and fewer elastic fibers than elastic arteries
  • Walls relatively thick
  • Capable of great vasoconstriction/ vasodilatation to adjust rate of blood flow
  • Also called distributing arteries
A

muscular arteries

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8
Q
  • Union of the branches of 2 or more arteries supplying the same body region
  • Provide alternate routes – collateral circulation
A

anastomoses

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9
Q
  • Abundant microscopic vessels
  • Metarteriole has precapillary sphincter which monitors blood flow into capillary
  • Sympathetic innervation and local chemical mediators can alter diameter and thus blood flow and resistance
  • Vasoconstriction can raise blood pressure
A

arterioles

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10
Q
  • smallest blood vessels conecting arterial outflow and venous return
  • microcirculation
  • exchange vessels
  • capillary beds arise form single metarteriole
A

capillaries

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11
Q

Flow from metarteriole through capillaries and into postcapillary venule

A

microcirculation(capillaries)

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12
Q
  • Primary function is exchange between blood and interstitial fluid
  • Lack tunica media and tunica externa
  • Substances pass through just one layer of endothelial cells and basement membrane
A

exchange vessels(capillaries)

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13
Q

– arise from single metarteriole

  • Vasomotion – intermittent contraction and relaxation
  • Throughfare channel – bypasses capillary bed
A

capillary beds

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14
Q
  • Continuous-Endothelial cell membranes form continuous tube
  • Fenestrated-Have fenestrations or pores
  • Sinusoids-Wider and more winding;Unusually large fenestrations
A

types of capillaries

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15
Q
  • Thinner walls than arterial counterparts
  • Postcapillary venule(Smallest venule)
  • Form part of microcirculatory exchange unit with capillaries
  • Muscular venules have thicker walls with 1 or 2 layers of smooth muscle
A

venules

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16
Q
  • Structural changes not as distinct as in arteries
  • very thin walls in relation to total diameter
  • Same 3 layers as arteries
    • Tunica interna thinner with little smooth muscle
    • Tunica interna thinner than arteries
    • Tunica externa thickest layer
  • Not designed to withstand high pressure
  • Valves – folds on tunica interna forming cusps
  • Aid in venous return by preventing backflow
A

veins

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17
Q
  • Largest portion of blood at rest is in systemic veins and venules
    • Blood reservoir
  • systemic arteries and arterioles
  • pulmonary vessels
  • systemic capillaries
  • heart
A

blood distribution(greatest to least)

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18
Q

Movement of substances between blood and interstitial fluid basic methods include diffusion, transcytosis, and bulk flow

A

capillary exchange

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19
Q
  • Substances move down their concentration gradient
  • O2 and nutrients from blood to interstitial fluid to body cells
  • CO2 and wastes move from body cells to interstitial fluid to blood
  • Can cross capillary wall through intracellular clefts, fenestrations or through endothelial cells
  • Most plasma proteins cannot cross
  • Except in sinusoids – proteins and even blood cells leave
  • Blood-brain barrier – tight junctions limit diffusion
A

Diffusion:Most important method

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20
Q
  • Small quantity of material
  • Substances in blood plasma become enclosed within pinocytotic vessicles that enter endothelial cells by endocytosis and leave by exocytosis
  • Important mainly for large, lipid-insoluble molecules that cannot cross capillary walls any other way
A

transcytosis

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21
Q
  • Passive process in which large numbers of ions, molecules, or particles in a fluid move together in the same direction
  • Based on pressure gradient
  • Diffusion is more important for solute exchange
  • Bulk flow more important for regulation of relative volumes of blood and interstitial fluid
    • Filtration – from capillaries into interstitial fluid
    • Reabsorption – from interstitial fluid into capillaries
A

bulk flow

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22
Q

balance of 2 pressures

NFP= (BHP + IFOP) – (BCOP + IFHP)

A

net filtration pressure

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23
Q
  • Blood hydrostatic pressure (BHP) generated by pumping action of heart
  • Falls over capillary bed from 35 to 16 mmHg
  • Interstitial fluid osmotic pressure (IFOP)
  • 1 mmHg
A

pressures that promote filatrion

24
Q
  • Blood colloid osmotic pressure (BCOP)
    • Due to presence of blood plasma proteins too large to cross walls
    • Averages 36 mmHg
  • Interstitial fluid hydrostatic pressure (IFHP)
    • Close to zero mmHg
A

Pressures that promote reabsorption

25
Q
  • Nearly as much reabsorbed as filtered
  • At the arterial end, net outward pressure of 10 mmHg and fluid leaves capillary (filtration)
  • At the venous end, fluid moves in (reabsoprtion) due to -9 mmHg
  • On average, about 85% of fluid filtered out of capillaries is reabsorbed
  • Excess enters lymphatic capillaries (about 3L/ day) to be eventually returned to blood
A

starling’s law

26
Q
  • total blood flow equals cardiac output
  • CO= heart rate X stroke volume

Distribution of CO depends on:

  • Pressure differences that drive blood through tissue
    • Flows from higher to lower pressure
  • Resistance to blood flow in specific blood vessels
    • Higher resistance means smaller blood flow
A

hemodynamics:factors affecting blood flow

27
Q
  • Contraction of ventricles generates blood pressure
  • Systolic(highest)/diastolic(lowest)
  • Pressure falls progressively with distance from left ventricle
A

blood pressure

28
Q

Opposition to blood flow due to friction between blood and walls of blood vessels depending on:

  • size of lumen
  • blood viscosity
  • total blood vessel length
A

vascular resistance

29
Q
  • Speed in cm/sec is inversely related to cross-sectional area
  • Velocity is slowest where total cross sectional area is greatest
  • Blood flow becomes slower farther from the heart
    • Slowest in capillaries
    • Aids in exchange
    • Circulation time – time required for a drop of blood to pass from right atrium, through pulmonary and systemic circulation and back
A

Velocity of Blood Flow

30
Q
  • Control blood pressure by adjusting heart rate, stroke volume, systemic vascular resistance, and blood volume
  • Some act faster that others
  • Some shorter- or longer-term
A

interconnected negative feedback systems

31
Q
  • In medulla oblongata
  • Groups of neurons regulate heart rate, contractility of ventricles, and blood vessel diameter
  • Cardiostimulatory and cardioinhibitory centers
  • Vasomotor center controls blood vessel diameter
  • Receives input from both higher brain regions and sensory receptors
A

location of cardiovascular center

32
Q
  • Helps regulate heart rate and stroke volume
  • Controls neural, hormonal, and local negative feedback systems that regulate blood pressure and blood flow to specific tissues
A

function of cardiovascular center

33
Q
  1. Baroreceptors – monitor pressure changes and stretch in blood vessel walls
  2. Proprioceptors – monitor movements of joints and muscles to provide input during physical activity
  3. Chemoreceptors – monitor concentration of various chemicals in the blood
  • Output from cardiovascular center flows along neurons of ANS
  • Sympathetic (stimulatory) opposes parasympathetic (inhibitory
A

reflex neural regulation of BP

34
Q
  • Pressure-sensitive receptors in internal carotid arteries and other large arteries in neck and chest
    • Carotid sinus reflex helps regulate blood pressure in brain
    • Aortic reflex regulates systemic blood pressure
  • When blood pressure falls, baroreceptors stretched less, slower rate of impulses to cardiovascular center
  • Cardiovascular center decreases parasympathetic stimulation and increases sympathetic stimulation
A

baroceptor relfexes

35
Q
  • Receptors located close to baroreceptors of carotid sinus (carotid bodies) and aortic arch (aortic bodies)
  • Detect hypoxia (low O2), hypercapnia (high CO2), acidosis (high H+) and send signals to cardiovascular center
  • Cardiovascular center increases sympathetic stimulation to arterioles and veins, producing vasoconstriction and an increase in blood pressure
  • Receptors also provide input to respiratory center to adjust breathing rate
A

chemoreceptor reflexes

36
Q
  • Hormones
    • Renin-angiotensin-aldosterone (RAA) system
    • Epinephrine and norepinephrine
    • Antidiuritic hormone (ADH)
    • Atrial natriuretic peptide (ANP)
  • Action
    • Help regulate BP and blood flow by
    • Altering CO
    • Changing systemic vascular resistance
    • Adjusting total blood volume
A

hormonal reg of BP

37
Q
  • Renin(released by kidney when blood volume falls or blood flow decreases) and angiotensin converting enzyme (ACE) act on substrates to produce active hormone angiotensin II
  • Raises BP by vasoconstriction and secretion of aldosterone (increases water reabsorption in kidneys to raise blood volume and pressure)
A

renin angiotensin aldosterone (RAA) system

38
Q
  • Released by adrenal medulla in response to sympathetic stimulation
  • Increases cardiac output by increasing rate and force of heart contractions
A

epinephrine and norepinephrine

39
Q
  • Produced by hypothalamus, released by posterior pituitary
  • Responds to dehydration or decreased blood volume
  • Causes vasoconstriction which increases blood pressure
A

ADH or vasopressin

40
Q
  • Released by cells of atria
  • Lowers blood pressure by causing vasodilation and promoting loss of salt and water in urine
  • Reduces blood volume
A

atrial natriuretic peptide (ANP)

41
Q
  • Ability of tissue to automatically adjust its blood flow to match metabolic demands
  • Demand of O2 and nutrients can rise tenfold during exercise in heart and skeletal muscles
  • Also controls regional blood flow in the brain during different mental and physical activities
  • Types of stimuli
  • Physical – temperature changes, myogenic response
  • Vasodilating and vasoconstricting chemicals which alter blood vessel diameter
A

autoreg of BP

42
Q
  • Systemic blood vessel walls dilate in response to low O2 to increase O2 delivery
  • Walls of pulmonary blood vessels constrict under low O2 to ensure most blood flows to better ventilated areas of lung
A

important diff bewtn pulmonary and systemic circulation in autoregulatory response

43
Q
  • Alternate expansion and recoil of elastic arteries after each systole
  • Strongest in arteries closest to the heart
  • Becomes weaker further from the heart
  • Normally same as heart rate
    • Tachycardia – rapid resting heart or pulse rate
    • Bradycardia – slow resting heart or pulse rate
A

pulse

44
Q
  • Pressure in arteries generated by left ventricle during systole and the pressure remaining in the arteries when the ventricle is in diastole
  • Pulse pressure=Difference between systolic and diastolic pressure
A

blood pressure

45
Q
  • Failure of the cardiovascular system to deliver enough O2 and nutrients to meet cellular needs
  • Causes characterized by inadequate blood flow to body tissues

Types

  1. Hypovolemic – due to decreased blood volume
  2. Vascular – due to inappropriate vasodilation
  3. Obstructive – due to obstruction of blood flow
A

shock

46
Q
  • ___exercise results in
    • Extensive vasodilation
    • Increased venous return
    • A rise in cardiac output
  • __ exercise results in
    • Increased blood flow to skeletal muscles
    • Restriction of blood flow to nonessential organs
A

light; heavy

47
Q
  • Carotid and aortic reflexes increase CO and peripheral vasoconstriction
  • Sympathetic nervous system elevates blood pressure
  • E and NE increase cardiac output and ADH enhances vasoconstriction
A

cardiovascular response to hemmohaging SHORT term

48
Q
  • Decline in capillary blood pressure recalls fluids from interstitial spaces
  • Aldosterone and ADH promote fluid retention
  • Increased thirst promotes water absorption across the digestive tract
  • Erythropoietin ultimately increases blood volume and improves O2 delivery
A

cardiovascular response to heorrhaging LONG term

49
Q
  • The Brain-Four arteries which anastomose insuring constant blood flow
  • The Heart-Coronary arteries arising from the ascending aorta
  • The Lungs-Pulmonary circuit, regulated by local responses to O2 levels;Opposite other tissues (declines in O2 cause vasodilation)
A

special circulation

50
Q
  • Peripheral distribution of arteries and veins is generally symmetrical
  • Except near the heart
  • Single vessels may have several names as they cross anatomical boundaries
  • Arteries and corresponding veins usually travel together
A

distribution of blood:general functional patterns

51
Q
  • Superior vena cava-Drains blood from the head and neck
  • Inferior vena cava-Drains blood from the remainder of the body
A

systemic veins

52
Q
  • Contains substance absorbed by the stomach and intestines
  • Delivers these compounds to the liver for
    • Storage
    • Metabolic conversion
    • Excretion
A

hepatic portal system

53
Q
  • Fetal blood flow to the placenta is supplied via paired umbilical arteries
  • A single umbilical vein drains from the placenta to the ductus venosus
    • Collects blood from umbilical vein and liver &Empties into the inferior vena cava
A

placental supply in fetal circulation

54
Q
  • No need for pulmonary function in the fetus
  • Two shunts bypass the pulmonary circuit
    • Foramen ovale
    • Ductus arteriosus
A

fetal circulation of the heart and great vessels

55
Q
  • Decreased hematocrit
  • Constriction or blockage of peripheral veins by a thrombus
  • Pooling of blood in the veins of the legs
  • Vessels are less elastic, prone to Ca2+ deposits and thrombi formation
  • The aging heart has reduced output, decreased activity, and scarring
A

age related changed in blood

56
Q
A

A&P2 (17 decks)

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