Shared Flashcard Set

Details

Chapter 21
Blood vessels and circulation
26
Anatomy
Undergraduate 2
02/02/2018

Additional Anatomy Flashcards

 


 

Cards

Term
Tunica Intima
Definition
the inner layer of a blood vessel
-arteries only have an internal elastic membrane
Term
Tunica media
Definition
the middle layer of a blood vessel, commonly the thickest layer
-contains concentric sheets of smooth muscle in loose connective tissue
-arteries only-exernal elastic membrane separates tunica media from tunica externa
Term
Tunica Externa (tunica adventitia)
Definition
the outer layer of a blood vessel
-it is a connective tissue sheath
-in veins, thicker than tunica media, contains elastic fibers and smooth muscle cells
Term
Vasoconstriction
Definition
contraction of arterial smooth muscle
Term
vasodilation
Definition
relaxation of arterial smooth muscle
Term
Elastic arteries (conducting arteries)
Definition
-large vessels (pulmonary trunk and aorta)
-transport large volumes of blood
Term
Muscular arteries (distribution arteries)
Definition
-medium sized
-superficial arteries-pressure points
Term
Arterioles
Definition
-small, little to no tunica externa
-thin or incomplete tunica media
-resistance vessels
Term
Capillaries
Definition
smallest vessels with thin walls, only vessels that can exchange materials with interstitial fluid
Term
Continuous capillaries
Definition
-Complete endothelial lining, found in all tissues except epithelia and cartilage
-permit diffusion of water, small solutes, and lipid-soluble materials into ISF
-prevent loss of blood cells and plasma proteins
Term
Fenestrated capillaries
Definition
-have pores in endothelial lining
-permit rapid exchange of water and large solutes between plasma and ISF
-found in choroid plexus, endocrine organs, kidneys, and intestinal tract
Term
Sinusoids
Definition
Gaps between adjacent endothelial cells in the liver, spleen, bone marrow, and endocrine organs
-Permit free exchange of water and large plasma proteins
Term
Capillary beds
Definition
-Connect arterioles to venules
Term
Thoroughfare channels
Definition
direct capillary connections between arterioles and venules
Wall in initial part of passageway controlled by smooth
muscle segments (metarterioles or precapillary arteriole)
Term
Collaterals
Definition
multiple arteries that contribute to one capillary bed
Term
Arterial anastomoses
Definition
fusion of 2 collateral arteries
Term
Arteriovenous anastomoses
Definition
direct connections between arterioles and venules
-regulated primarily by sympathetic innervation (cardiac centers in medulla oblongata)
Term
Angiogenesis
Definition
formation of new blood vessels under direction of vascular endothelial growth factor
Term
Vasomotion
Definition
Contraction and relaxation cycle of capillary sphincters
Term
Venules
Definition
very small veins, lack tunica media
collect blood from capillaries
Term
medium-sized veins
Definition
-Thin tunica media and few smooth muscle cells
-Tunica externa with longitudinal bundles of elastic fibers
Term
Large veins
Definition
-all 3 tunica layers
-thick tunica externa
-thin tunica media
-include superior/inferior vena cava
Term
Distribution of blood
Definition
Heart, arteries, capillaries: 30-35% of blood volume
Venous system: 65-70% of blood volume in liver, bone marrow, and skin
Term
Capacitance
Definition
Ability of a blood vessel to stretch
Term
Venoconstriction
Definition
Systemic veins constrict, decreases the amount of blood in the venous system, increases the volume within the arterial system and capillaries
Term
Venous valves
Definition
 Folds of tunica intima
 Prevent blood from flowing backward
 Pressure is so low, cannot overcome gravity
 Any compression of vein pushes blood toward heart- improves venous return
Supporting users have an ad free experience!