The circulary system = HEART // BLOOD VESSELS // BLOOD => Maintains homeostasis !
1. The components and functions of blood
Blood = Specialized CONNECTIVE TISSUE with 3 crucial tasks : TRANSPORTATION / REGULATION / DEFENSE
M~5-6L – W~4-5L (= 8% of body weight)
Plasma (55%) = Liquid component
Formed elements (45%) = cellular components (RBCs, WBCs, Platelets)
PLASMA (55%) =vWater & dissolved solutes
Plasma : transport medium for BCs and platelets : 90% water – rest = solutes,mainly PROTEINS :
Albumins:
o keep water balance between blood & interstitial fluid
o Manufactured in the liver = also binds to & transports biluribin & drugs
Globulins :
o Tansports various substances
o Beta-Globulins : binds to lipid molecules (eg. cholesterol) => forms a “LIPOPROTEIN” eg. LDL (Low-density
lipoproteins) (=bad cholesterols) and HDLs (=good choleterols).
o Gamma-Globulins : help protect against illness & infections
Clotting proteins :
o minimize bloodloss & help restore homeostasis after injury
Also contains ELECTROLYTES (eg Ca & Ka to controll cell function/volumes), HORMONES (chemical messengers from
endocrine system), NUTRIENTS, WASTE products (eg urea, carbon dioxide), GASES (eg oxygen).