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Side ASide B
three principle categories of blood vessels
arteries, veins & capillaries
efferent vessels- carry blood away from heart
afferent vessels- carry blood back to heart
microscopic, thin walled vessels that connect the smallest arteries to teh smallest veins
walls of arteries are composed of 3 layers of
lines inside of the vessel- exposed to blood- consists of simple squamos epith called endothelium
mid layer- thickest-smooth muscle, collagen,elastic tiss- strengthen the vess and prevent bp...
changes in diameter of a blood vessel
outer most layer- loose connect tiss often merges w. neigh vess anchors the vess and provides...
small vessels that supply blood to at least the outer half of the wall of a larger vessel
a.k.a arteries. bc relatively strong resilient tiss struct that resists high bp- constructed...
conducting ( elastic or large) arteries
BIGGEST-expand during ventricular systole to receive blood& recoil during diastole.sub to highest...
Distributing (muscular or medium) arteries
smaller branches that distrib blood to specif organs- interestate highway- 40 layers of smooth...
resistance ( small) arteries
too variable in # and location to be given individual names- 25 layers of smooth musc & relatively...
smallest of the resistance arteries 40-200Mm w/ only one to 3 layers of smooth muscle
short vessels that link arterioles and capillaries. have individual muscle cells spaced a short...
encircles entrace to 1 capillary. constrict. shuts off blood flow through their respect cap&diverts...
baroreceptors(press sensors) respond to changes in bp- wall of intern carotid artery- monitor...
oval recept-3x5mm-sensory fivers of vagus&gloss nerves-monitor blood CO2 O2 and PH
one to three chemorecptors located in oartic arch near arteries in head & arms- monitor blood...
composed of only an endothelium & bment memb-walls .2-.4 mm
where are capillaries scarce?
tendons & ligaments & absent from epithelia, cornea, and lens, and most cartilage
3 types of capillaries
continuous, fenestrated, sinusoids
occur in most tissues- enothelial cells-tight juncts-uninterrupted tube- exhibit pericytes
filtration pores-allow for rapid passage of molecs butretain blood cells & platelets in bstream-kidnesys,endoglands,small...
irregular, highly porous blood spaces in such tissues as liver, spleen& b. marrow-twisted-conform...
lie external to endothelium- contractile proteins- diff into endothelial & smooth mesc cells...
capillaries organized into these networks- 10 to 100 caps/metarteriole. they continue > thoroughfare...
leads directly to a venule
a.k.a veins- thin walled & flaccid-exp easily to accom an inc vol of blood- greater capactiy...
smaller veins are calledexih
smallest veins-exch fluid with the tissues- very porous
receive blood from postcap venules- up to 1mm in diam- have tunica media of 1 or 2 layers...
up to 10mm-most veins w. individ names-exhibit infoldings of tunica interna to meet in midd...
failure of venous valves- ppl who stand long time-obesity and preg can promote- press on large...
varicose veins of anal canal
veins w. esp thin walls, large lumens, and no smooth musc- ex. coronary sinus of heart- NOT...
greater than 10mm- venae cavae, pulmon veins, internal jug, renal veins