7/18/2019 Circulatory System

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Circulatory system

Arteries

tunica externica-collogen fbers

tunica media-smooth muscle, elastic fbers

tunica intima- endothelial cells

Small lumen

no valves -except the aorta

(#histology)

Veins

Valves (to prevent bac!o")

arger lumen

Capillary- single layer o$ endothelial cells -rapid di%usion

&lood- blood is the only li'uid tissue, and has regulatory $unctions(body

temperature, stabilies p, contains bu%ers), de$ends the body against in$ections

example phagocytosis*

Component o$ blood-plasma, cells($ormed elements+ blood cells platelets)

lasma is the li'uid part o$ the bood (./ percent is "ater, . percent-0 percent o$

that is "aste products, gases, hormones, ions, nutrients and vitamins, the

remaining 1 percent is plasma proteins (albumins, globulins and fbrinogen)

&lood cells- red, "hite, platelets (all three arise $rom stem cells in the bone marro")

(#page 230 &45 SC4 / and 0)

6ed blood cells-Arithrocytes

7hite blood cells- granulocytes(cystoplasms are flled "ith granules) and

agranulocytes