circulation

LDL (Low Density Lipoproteins)

people at risk for atherosclerosis may have fewer LDL receptors in the liver, leads to higher LDL levels; LDL carriers are more likely to penetrate arterial endothelium

HDL (High Density Lipoproteins): cholesterol may

also be transported through the blood as high density lipoproteins (HDLs)

HDLs are

too large to penetrate arterial endothelium; HDL levels are generally higher in people who get regular aerobic exercise → lower risk of developing atherosclerosis

blood clotting: when a blood vessel is damaged, a number of physiological processes are initiated that promote hemostasis

vasoconstriction, formation of a platelet plug, and production of a web of fibrin

platelet plug: release of thromboxane A2 from platelets

makes other platelets sticky; the second layer of platelets undergoes platelet degranulation

a platelet plug is formed in the damaged vessel & further strengthened by a

meshwork of insoluble protein fibers known as fibrin

conversion of fibrinogen to fibrin occurs through two different pathways

intrinsic pathway and extrinsic pathway; these pathways converge to stimulate conversion of prothrombin to thrombin because thrombin converts fibrin

dissolution of clots: as the damaged blood vessel wall is repaired, additional

enzymes are activated to break up the clot; plasminogen →plasmin

blood typing: on the surface of all cells in the body, there are certain molecules (usually proteins) that

serve as “self” markers; antigens

blood typing:

red blood cells express a few antigens

type A

A antigens only

type B

B antigens only

type AB

A & B antigens

type O

neither A or B antigens

erythropoietin stimulates the production of

erythrocytes; secreted by the kidney in response to lower oxygen levels in the blood.

dissolution of clots: other drugs are effective anticoagulants

EDTA binds up Ca2+, heparin inactivates thrombin, aspirin inhibits the production of prostaglandins

plasma proteins are

7-9% of the plasma

plasma proteins: albumin exerts

osmotic pressure & is required to maintain blood volume & pressure

plasma proteins: globulins transport

lipids & fat soluble vitamins & have immune functions

plasma proteins: fibrinogen is

important for blood clotting

ischemic heart disease: a tissue is said to be ischemic when

it receives an inadequate supply of oxygen; reduced blood flow

angina pectoris: temporary insufficiency of

oxygen to the heart

anginal pain is a

sudden, sever, & pressing pain that begins behind the breast bone & can radiate to the left shoulder & arm

classic angina (exertional angina)

large coronary vessels are obstructed by atherosclerosis; increased exertion precipitates the angina

atherosclerosis

fatty deposits develop underneath the lining of the blood vessels