final chp. 21 Flashcards
blood vessels
arteries, arterioles, capillaries, venules, veins, aorta, pulmonary trunk
arteries
carry blood away from the heart
arterioles
smallest branches of arteries
capillaries
smallest blood vessels, thin walls
material exchange between blood and interstitial fluid
venules
collect blood from capillaries
veins
return blood to the heart
aorta
send blood from left ventricle to systemic circulation
elastic
pulmonary trunk
send blood from right ventricle to pulmonary circulation
major vein
tunica intima (inner layer)
present in all vessels
internal elastic membrane: endothelial cells with CT sheath
tunica media (middle layer)
sheets of smooth muscle in loose CT in the external elastic membrane
tunica externa (outer layer)
present in large vessels
has collagen and elastic fibers, anchors vessel to adjacent tissues
found in veins smooth muscle
arteries vs veins
run side by side,
thick walls, higher pressure, small, round
round vs flat, thin, large lumen
rippled vs smooth endothelium that contracts
arteries have an internal & external elastic membrane
collage, elastic fibers
veins have smooth muscle cells and valves
smooth muscle tissue
found in blood vessels and airways
non striated
regulates BP and airflow
long, slender & spindle shaped with a nucleus
smooth muscle contractions
thin filaments attached to dense bodies that transmit contractions from cell to cell
smooth muscle excitation contraction coupling
Ca 2+ in sarcoplasm triggers contraction
Ca 2+ binds to calmodulin in the sarcoplasm
this activates myosin light chain kinase (MLCK)
MLCK breaks down ATP to initiate contraction
capillary beds (plexus)
connect arteriole to venule
precapillary sphincters guard entrances, control blood flow
have multiple arteries (collaterals)
thoroughfare channels
direct connections between arterioles and venules controlled by smooth muscle segments
arterial anastomoses
fusion of two collateral arteries
filtration at capillary beds
driven by hydrostatic pressure that drives material out through the capillary wall
leaves large solutes in the bloodstream
reabsorption at capillary beds
happens due to OP (osmotic pressure)
NFP = CHP vs BCOP
net filtration pressure
capillary hydrostatic pressure vs blood colloid osmotic pressure
hepatic portal system
detours venous blood from GI tract to liver then to the heart
hepatic portal vein: splenic and mesenteric veins
gastric and portal vein merge together
portal vein
delivers glucose and amino acids from the GI tract directly to the liver before sending it to the heart
