A&P Exam 2 Flashcards
(273 cards)
what are large arteries called?
elastic conducting arteries
what are medium arteries called?
muscular distributing arteries
what are small arteries called?
resistance arteries or arterioles
what are small veins called? medium veins?
post capillary venues, and muscular venues
what makes up the tunica intima
simple squamous epithelium cells, the basement membrane, and in arteries an internal elastic membrane
what makes up the tunica media?
smooth muscle, collagen, elastic fibers, and external elastic membrane in arteries
what is the tunica externa or adventita made of?
lost connective tissue and the vasa vasorum
describe the elastic (conducting arteries, where are they located?
in the pulmonary trunk, aorta, carotids, subclavian arteries, common iliac arteries. they are pressure reservoirs
describe muscular (distributing) arteries
they distribute blood to specific organs, have a thicker tunica media in proportion to their lumen
describe arterioles
no elastic laminae, has little tunica externa, has a thicker tunica media compared to elastic arteries (proportionally), and have the greatest point of control over where the blood is distributed
where is the pressure largest in the veins and arteries?
the largest veins and arteries
which veins/arteries have the most elastic fibers?
the larger ones
which veins/arteries have more smooth muscle?
venules and arterioles
atherosclerosis
hardening of large conducting arteries due to a buildup of plaque in the vessels
what allows for diffusion within capillaries?
simple squamous epithelium
describe precapillary sphincters
they regulate flow into “true” capillaries, are made up of single smooth muscle cells, allow for the micromanagement of volume in capillary beds, and controls routing of blood through organs.
what occurs when pre capillary sphincters relax? contract?
when they relax, they allow perfusion through the capillaries, when they contract, they block the blood from going through the capillary bed and bypass it.
describe continuous capillaries
they’re the least permeable, most common, have tight junctions which hold endothelial cells together, and have intercellular clefts
describe fenestrated capillaries
hold large amount of materials that need to be rapidly filtered, are in the kidneys and small intestines
describe sinusoid capillaries
the most permeable capillary, don’t have a basement membrane, large molecules/entire cells move in an out of circulation, are in spleen, bone marrow, and liver
what are some characteristics of veins and venules?
large lumen, low pressure, slow (steady) flow, blood reservoirs
describe muscular venules
1-2 layers of smooth muscle in tunica media, have a thin tunica externa
describe medium veins
have a thin tunica media, and thick tunica externa, tunica interns forms the venous valves (varicose veins form as a result of not forming these valves)
what propels venous blood back to the heart?
skeletal muscle pump