blood vessels pt.1 Flashcards
efferent vessels
arteries
carry blood aways from the heart. Blood is oxygenated except in pulmonary circulation and umbilical vessels of fetus
arteries
afferent vessels
veins
Vessels carrying blood back to heart. Blood is deoxygenated except for pulmonary circulation and umbilical vessels of fetus
veins
Connects smallest arteries to smallest veins, creating a circuit. In direct contact with tissue cells
capillaries
Usually round with thick wall. carries blood away from the heart. efferent vessels
arteries
Usually flattened with a thin wall. Carries blood toward the heart. Has more smooth muscle. afferent vessels
Veins
tunic layers of veins and arteries (3)
tunica intima, tunica media, tunica externa
space all vessels provide for blood to pass through. surrounded by endothelium/tunica intima
lumen
capillary only have an _______ layer surrounded by sparse amounts of ____ _____.
endothelium, basal lamina
Innermost layer containing endothelial cells. Has connective tissues with elastic fibers.
Tunica intima aka tunica interna
In _____, the tunica intima has an outer marginal layer of ____ ____ (internal elastic membrane).
arteries, elastic fibers
Middle layer containing concentric sheets of smooth muscle.
tunica media
Contraction of smooth muscle in tunica media causes _________, a decrease in vessel diameter. Relaxation of smooth muscles cause _________, an increase in vessel diameter.
vasoconstriction, vasodilation
Separates tunica media from tunica externa
external elastic membrane
Connective tissue sheath forming outer most tunic layer in typical blood vessel. Anchors vessel to surrounding tissues.
Tunica externa/tunica adventitia
Layer contains collagen and scattered elastic fibers in artery. Generally thicker in veins than tunica media.
tunica externa aka tunica adventitia
Arteries, arterioles, capillaries, venules, veins
general blood vessel classes (5)
Large vessels close to the heart that stretch and recoil when heart beats. Includes pulmonary trunk, aorta, and branches.
elastic arteries
Medium-sized arteries which distribute blood to skeletal muscles and internal organs.
muscular arteries
Poorly defined tunica externa. Tunica media is only 1–2 smooth muscle cells thick
arterioles
Only blood vessels to allow exchange between blood and interstitial fluid. Very thin walls allow easy diffusion.
capillaries
Small veins. Lack a tunica media and resemble expanded capillaries. Collect blood from capillaries
venules
Thin tunica media with smooth muscle cells and collagen fibers. Thickest layer is tunica externa with longitudinal collagen and elastic fibers
medium-sized veins
Includes superior venae cava, inferior venae cava and tributaries. Contain all three vessel wall layers. Thin tunica media surrounded by thick tunica externa.
large veins
In between artery tunica layers. Absent or minimal in vein. Allows expansion/contraction
external elastic membranes
