Lesson 9

ajv09c's version from 2015-04-29 18:44

Section 1

Question Answer
Blood vessels are instrumental in overall cardiovascular regulation
types of blood vesselsarteries arterioles cappilaries venules veins
arteriescarry blood away from heart
arteriolessmallest branches of arteries
capillariessmallest blood vessels; location of exchange between blood and interstitial fluid
venulescollect blood from cappilaries
veinsreturn blood to heart

Section 2

Question Answer
the largest blood vessels are attachedto the heart
pulmonary trunk carries bloodfrom right ventricle to pulmonary circulation
aorta carries blood fromleft ventricle to systemic circulation
capillarieshave small diameter and thin walls; chemicals and gasses diffuse across walls

Section 3

Question Answer
structure of vessel wallswalls have three layers; tunica intima, tunica media, tunica external
tunica intima inner layer; includes endothelial lining, connective tissue layer, internal elastic membrane
internal elastic membraneain arteries, is a layer of elastic fibers in outer margin of tunica intima
tunica mediamiddle layer; contains concentric sheets of smooth muscle in loose connective tissue; binds to inner and outer layers; has external elastic membrane
external elastic membraneseparates tunica media from tunica externa
tunica externaouter layer; anchors vessel to adjacent tissues in arteries; consists of collagen fibers and elastic fibers
in veins tunica externa containselastic fibers and smooth muscle cells

Section 4

Question Answer
differences between arteries and veins (arteries)arteries and veins run side by side; arteries have thicker walls and higher blood pressure; arteries have small round lumen; artery lining folds; arteries more elastic
differences between arteries and veins (veins)vein has a large flat lumen; vein lining contracts; veins have valves

Section 5

Question Answer
arteries- elasticity allowsarteries to absorb pressure waves that come with each heartbeat
arteries- contractilityarteries change diameter; controlled by sympathetic division of ans; vasodilation and vasoconstriction
vasoconstriction contraction of arterial smooth muscle by the ANS
vasodilationrelaxation of arterial smooth muscle; enlarges lumen
vasodilation and vasoconstriction affectafter load on heart; peripheral blood pressure; capillary blood flow
arteries change from heart to capillariesfrom elastic arteries; to muscular arteries; to arterioles

Section 6

Question Answer
elastic arteries akaconducting arteries
elastic artery characteristicslarge vessels (pulmonary trunk; aorta); tunica media has many elastic fibers and few muscle cells; elasticity evens out pulse force
muscular arteries akadistribution arteries
muscular artery characteristicsare medium sized; most arteries of the arterial system; tunica media has many muscle cells
arteriolessmall arteries; have little or no tunica externa; have thing or incomplete tunica media
artery diameter changes withsympathetic or endocrine stimulation in small muscular arteries and arterioles
constricted arteries opposeblood flow which creates resistance
resistance vesselsarterioles
aneurysmbuldge in arterial wall
aneurysm caused byweak spot in elastic fibers; pressure may rupture vessel if elastic component fails
strokeaneurysm in brain

Section 7

Question Answer
microscopic capillary networks permeateall active tissues
capillary functionlocation of all exchange functions of cardio vascular system
capillary function- materials diffuse between blood and interstitial fluid
capillary structureendothelial tube inside thin basement membrane
diameter of capillarysimilar to red blood cell
capillaries lacktunica media; tunica externa
continuous capillarieshave complete endothelial lining; are found in all tissues except epithelia and cartilage
functions of continuous capillariespermit diffusion of water, small solutes, and lipid soluble materials; block blood cells and plasma proteins
fenestrated capillarieshave pores in endothelial lining; permit rapid exchange of water and larger solutes between plasma and interstitial fluid
fenestrated capillaries are foundin choroid plexus, endocrine organs, kidneys, intestinal tract
sinusoids (sinusoidal capillaries)have gaps between adjacent endothelial cells; permit free exchange of water and large plasma proteins between blood and interstitial fluid; phagocytic cells monitor blood at sinusoids
sinusoids are foundin liver, spleen, bone marrow, endocrine organs

Section 8

Question Answer
capillary beds (capillary plexus)connect one arteriole and one venule
percapillary sphinctersmooth muscle cells; guards entrance to each capillary; opens and closes causing capillary blood to flow in pulses
thoroughfare channelsdirect capillary connections between arterioles and venules
thoroughfare channels controlled bysmooth muscle segments called metarterioles
collateralsmultiple arteries that contribute to one capillary bed; allow circulation if one artery is blocked
arterial anastomosisfusion of two collateral arteries
arteriovenous anastomosesdirect connections between arterioles and venules; bypass the capillary bed

Section 9

Question Answer
veins collect blood fromcapillaries in tissues and organs
veins returnblood to the heart
veins are larger indiameter than arteries
veins have thinnerwalls than arteries
veins have lowerblood pressure
venulessmall in size; collect blood from capillaries

Section 10

Question Answer
medium sized veinssimilar in size to muscular arteries
medium sized veins tunica mediathin and few smooth muscle cells
medium sized veins tunica externalongitudinal bundles of elastic fibers
large veinshave all three tunica layers; thick tunica externa; thin tunica media
venous valvesfolds of tunica intima; prevent blood from flowing backward;
compression of venous valve pushesblood toward the heart
vericose veinsveins where valves malfunction and allow blood to pool
valve opens superior to contracting muscles
valve closes inferior to contracting muscle
distribution of bloodheart arteries and capillaries-30-35% of blood volume; venous system 60-65% of blood volume
1/3 of venous blood is inlarge venous networks of the liver, bone marrow, and skin

Section 11

Question Answer
venous response to blood lossvasomotor center stimulates sympathetic nerves
venous response to blood loss- system veinsconstrict (venoconstriction) can increase blood volume in arteries and capillaries to near normal levels even in cases of severe blood loss
venous response to blood loss- veins in liver skin and lungsredistribute venous reserve (20% of total blood volume)
total capillary blood flowequals cardiac output (CO); determined by pressure and resistance in the cardiovascular system
pressure is generated by? to? the heart to overcome resistance
absolute pressure is less important than pressure gradient
pressure griant delta pcirculatory pressure; difference between pressure at the heart and pressure at peripheral capillary beds
flow (F) proportional to the pressure difference (delta p) divided by R
blood pressure (BP) arterial pressure (mm Hg)
capillary hydrostatic pressureCHP; pressure within the capillary beds
venous pressurepressure in the venous system
circulatory pressuredelta P across systemic (about 100 mm Hg)
circulatory pressure must overcometotal peripheral resistance
total peripheral resistanceR of entire cardiovascular system
Total peripheral resistance is caused byvascular resistance; blood viscosity; turbulence

Section 12

Question Answer
vascular resistance due tofriction between blood and vessel walls
vascular resistance depends onvessel length and vessel diameter
adult vessel lengthis constant; angiogenesis usually does not occur in adults
vessel diameter varies by vasodilation and vasoconstriction
viscosity R caused by molecules and suspended materials in a liquid
Whole blood viscosityis about four times that of water
water viscsity and molasses viscositywater is 1 molasses is 300
turbulenceswirling action that diusturbs smooth flow of liquid
turbulence occursin heart chambers and great vessels
turbulence sledom occursin smaller vessels unless they have wall damage;
asthersclerotic plaques causeabnormal turbulence