General Anatomy of Blood Vessels Flashcards Table View


three principle categories of blood vessels arteries, veins & capillaries
arteries efferent vessels- carry blood away from heart
veins afferent vessels- carry blood back to heart
capillaries microscopic, thin walled vessels that connect the smallest arteries to teh smallest veins
walls of arteries are composed of 3 layers of tunics
tunica interna lines inside of the vessel- exposed to blood- consists of simple squamos epith called endothelium
tunica media mid layer- thickest-smooth muscle, collagen,elastic tiss- strengthen the vess and prevent bp from rupturing them & to provide vasomotion
vasomotion changes in diameter of a blood vessel
tunica externa outer most layer- loose connect tiss often merges w. neigh vess anchors the vess and provides pass4small nerves, lymph vess& smaller blood vess
vasa vasorum small vessels that supply blood to at least the outer half of the wall of a larger vessel
resistance vessles a.k.a arteries. bc relatively strong resilient tiss struct that resists high bp- constructed to w/stand surges
conducting ( elastic or large) arteries BIGGEST-expand during ventricular systole to receive blood& recoil during diastole.sub to highest bp& have elastic tiss
Distributing (muscular or medium) arteries smaller branches that distrib blood to specif organs- interestate highway- 40 layers of smooth musc
resistance ( small) arteries too variable in # and location to be given individual names- 25 layers of smooth musc & relatively little elastic tiss
arterioles smallest of the resistance arteries 40-200Mm w/ only one to 3 layers of smooth muscle
metarterioles short vessels that link arterioles and capillaries. have individual muscle cells spaced a short distance apart each forming a precap sphinct
precapillary sphincter encircles entrace to 1 capillary. constrict. shuts off blood flow through their respect cap&diverts blood to tiss or organs elsew
cartoid sinuses baroreceptors(press sensors) respond to changes in bp- wall of intern carotid artery- monitor bp
carotid bodies oval recept-3x5mm-sensory fivers of vagus&gloss nerves-monitor blood CO2 O2 and PH
aortic bodies one to three chemorecptors located in oartic arch near arteries in head & arms- monitor blood comp
blood capillaries 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
continuous capillaries occur in most tissues- enothelial cells-tight juncts-uninterrupted tube- exhibit pericytes
fenestrated capillaries filtration pores-allow for rapid passage of molecs butretain blood cells & platelets in bstream-kidnesys,endoglands,small I, choroid plex
sinusoids irregular, highly porous blood spaces in such tissues as liver, spleen& b. marrow-twisted-conform to shape of surround tiss-gaps
pericytes lie external to endothelium- contractile proteins- diff into endothelial & smooth mesc cells & thus contrib to vess growth & repair
capillary beds capillaries organized into these networks- 10 to 100 caps/metarteriole. they continue > thoroughfare channel
thoroughfare channel leads directly to a venule
capacitance vessles a.k.a veins- thin walled & flaccid-exp easily to accom an inc vol of blood- greater capactiy for blood contain. than arter. steady flow of blood
smaller veins are calledexih tributaries
postcapillary venules smallest veins-exch fluid with the tissues- very porous
muscular venules receive blood from postcap venules- up to 1mm in diam- have tunica media of 1 or 2 layers of smooth musc & a thin tunica ext
medium veins up to 10mm-most veins w. individ names-exhibit infoldings of tunica interna to meet in midd of lumen forming venous valves
varicose veins failure of venous valves- ppl who stand long time-obesity and preg can promote- press on large veins & obstruct drainage to legs.
varicose veins of anal canal hemorrhoids
venous sinuses veins w. esp thin walls, large lumens, and no smooth musc- ex. coronary sinus of heart- NOT capable of vasomotion
large veins greater than 10mm- venae cavae, pulmon veins, internal jug, renal veins
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