BIOL G220: Ch. 23 Flashcards
Lectures and terms from Ch. 23: Blood Vessels
three classes of blood vessels
arteries
veins
capillaries
arteries carry blood…
away from the heart and become progressively smaller as they branch and finally result in capillaries
veins return blood..
to the heart and become progressively larger as they merge and are closer to the heart
tunics
layers covering blood vessels
tunics (inner to outer)
- tunica intima
- tunic media
- tunica externa
tunica intima
composed of endothelium and a subendothelial layer of areola connective connective tissue
endothelium
simple squamous epithelium lining the blood vessel lumen
tunic media
comprised of circularly arranged smooth muscle;
Sympathetic input causes smooth muscle to contract resulting in _____ whereas parasympathetic input results in ____
vasoconstriction; vasodilation
tunica externa
connective tissue that helps anchor the blood vessel to an organ
larger blood vessels require the own ___ ___
blood supply
smaller arteries that supply the larger arteries are called ___ ____, which run through the tunica externa
vaso vasorum
artery vs. vein: lumen diameter
artery: narrower than vein lumen
vein: wider than artery lumen; often appears collapsed when cut in cross section
artery vs. vein: general wall thickness
artery: thicker than companion vein
vein: thinner than companion artery
artery vs. vein: cross-sectional shape
artery: retains its circular cross-sectional shape
vein: cross section ends to flatten (collapse) if no blood is in the vein
artery vs. vein: thickest tunic
artery: tunica media
vein: tunica externa
artery vs. vein: elastic and collagen fibers in tunics
artery: more than in vein
vein: less than in artery
artery vs. vein: valves
artery: valves
vein: present in most veins
artery vs. vein: blood pressure
artery: higher than in veins (larger arteries is typically > 90 mm Hg)
vein: lower than arteries (about 2 mm Hg)
artery vs. vein: blood flow
artery: transports blood away from heart
vein: transports blood to heart
artery vs. vein: blood oxygen levels
artery: systemic arteries transport blood high in oxygen, pulmonary arteries transport blood low in oxygen
vein: systemic veins transport blood low in oxygen, pulmonary veins transport blood high in oxygen
types of arteries (3)
- elastic arteries
- muscular arteries
- arterioles
elastic arteries
largest arteries with elastic fibers in all three tunics allowing arteries to stretch under increased pressure generated by blood ejected from the heart
elastic arteries branch into..
muscular arteries