Ch 19 The Cardiovascular System Blood Vessels Part A

Delivery system of dynamic structures that begins and ends at the heart

Carry blood away from the heart oxygenated except for pulmonary circulation and umbilical vessels of a fetus

Contact tissue cells and directly serve cellular needs

Carry blood toward the heart

Tunica intima, tunica media, and tunica externa

Central blood containing space

Endothelium sparse basal lamina

Endothelium lines the lumen of all vessels
in vessels larger than 1mm, a subendothelial CT basement membrane is present

Smooth muscle and sheets of elastin
sympathetic basomotor nrve fibers control vasoconstriction and vasodilaiton of vessels

Collagen fibers protect and reinforce
larger vessels cotain vasa vasorum to nourish the external layer

Large thick walled arteries with elastin in all three tunics
aorta and its major branches
large lumen offers low resistance
act as pressure reservoirs expand and recoil as blood is ejected from the heart

Distal to elasticarteries deliver blood to body organs
have thick tunica media with more smooth muscle
active in vasoconstriction

Smalllest arteries
lead to capillary beds
control flow into capillary beds via vasodilation and vasoconstriction

Microsopic blood vessels
walls of thin tunica intima one cell thick
pricytes help stabilize their walls and control premeability
size allows only a singl RBC to pass at a time

All tissues except for cartilage epithelia cornea and lense of eye