BIOL 121 Lecture Notes - Lecture 31: Hmg-Coa Reductase, Mean Arterial Pressure, Adenylyl Cyclase
Document Summary
Factors that determine pp: stroke volume, speed of ejection of sv, arterial compliance. Pulse pressure (pp) = systolic pressure (sp) diastolic pressure (dp) Mean arterial pressure (map) = dp + (1/3)pp. As norepi and epi bind beta-1 adrenergic receptors, (a g-protein coupled receptor) on the plasma membrane of cardiac muscle cells. Inhibiton of hmg coa reductase (rate-controlling enzyme of pathway that produces cholesterol. Increases # of ldl receptors (more cholesterol being absorbed into liver, less blood. Other effects: reduced vascular inflammation, reduced platelet aggregation, stabilization of atherosclerotic plaque, mild immunosuppression. Capillaries are composed of a single layer of epithelial cells (no smooth muscle/elasticity). Total cross sectional area of arteries = ~40 cm2, while total cross sectional area of capillaries = 1,400 cm2. Proteins are exchanged between capillaries and interstitial fluid is done via endo- and exocytosis. O2 & co2 diffuse freely across the endothelial cell membranes.
