Ch 20 - Blood Vessels Flashcards
tunica intima and what its made of
the endothelium of the blood vessel; made of simple squamous epithelium
tunica media
circular smooth muscle in the blood vessel, wraps around tunica intima
which type of vessel (artery or vein) has a thicker tunica media
the arteries
tunica externa
connective tissue that makes up the outside of the blood vessel
which vessel type has a thicker tunica externa (artery or vein)
vein
which vessel type was a wider lumen (artery or vein)
vein (more blood in veins at rest than in arteries)
What do veins have that arteries don’t
- unidirectional valves
- skeletal muscle pumps
what are the two layers that make up capillaries
basement membrane and endothelial cells
arterioles are controlled by the ___
ANS
arterioles are always slightly ___ at all times
constricted; this way there’s room for vasodilation if needed
capillaries are just wide enough to allow _____ passage of RBCs
single-file
pre-capillary sphincters are isolated to the ______. This occurs during exercising or fight-or-flight
mesenteric vasculature (associated with the intestines)
when sphincters are closed, blood passes through the _____ and bypasses _____
metarteriole; true capillaries
4 routes that molecules pass through capillaries
- Diffusion through endothelial cell membranes (O2, CO2)
- Intercellular clefts
- Pinocytotic vesicles
- Fenestrations
what is the exception to the ways that molecules pass through capillaries
the blood-brain barrier. no fenestrations, or clefts, completely tight junctions, glucose is “ushered” across the walls
