Flashcards in blood vessels Deck (19):
what is the inner most layer of the blood vessels?
tunica interna- it is single layer of squamous epithelial cells also called endothelium.
what is the tunica externa?
outer most layer of the blood vessel made of collagen fibers.
what is the middle layer of the blood vessels?
tinica media-smooth muscle and elastic connective tissue
which type of blood vessel takes blood away from the heart?
what do arteries do?
arteries squeeze blood to force it forward, they have a high blood pressure and a very thick tunica media.
what are conducting (elastic) arteries and what is the function?
aorta and major branches conduct large amounts of blood to large body regions. they have lots of elastic tissue to allow them to expand.
which type of artery is medium sized, distributes blood to specific body areas or organs, has less elastic tissue?
distributing (muscular arteries)
what are arterioles and what is the function?
arterioles are tiny arteries that send blood into capillaries, often have smooth muscle, arranged as sphincters.
what are tiny blood vessels in tissues of organs and what is the function?
capillaries- form networks in organs called capillary beds. only have tunica interna
what are continuous capillaries?
cells have no holes in them, most capillaries are this way
which type of capillary has epithelial cells, has holes that makes them "leaky"?
which type of capillary has huge holes in and between cells super leaky and what is an example?
sinusoid capillary- example:liver
what is the name for little veins that drain capillary beds?
venules (same as veins just smaller)
what is the function of veins?
takes blood back to the heart (venules also)
what kind of tunica do veins have?
thin tunica media
-veins cant squeeze blood
-veins are stretch but not elastic
-veins have very low blood pressure.
-veins run through skeletal muscles
how do veins prevent blood from "falling"?
they have an internal valve
what makes blood move forward?
contraction of skeletal muscles moves blood forward