Blood Vessel Physiology Flashcards
(13 cards)
What determines blood flow?
Blood flow = Pressure gradient ÷ Resistance
What factors increase resistance to blood flow?
Smaller vessel radius (most important), longer vessel length, and higher blood viscosity.
What are the types of blood vessels?
Arteries (carry blood away), arterioles (resistance vessels), capillaries (exchange), venules (collect blood), veins (return to heart).
What role do arteries play in circulation?
They act as pressure reservoirs, maintaining blood flow during diastole through elastic recoil.
What is systolic vs. diastolic pressure?
Systolic = pressure during ventricular contraction; Diastolic = pressure during relaxation.
What is pulse pressure and MAP?
Pulse Pressure = Systolic - Diastolic
MAP = Diastolic + 1/3(Pulse Pressure)
How is arteriole diameter regulated?
Locally by metabolites and myogenic responses; systemically by sympathetic input and hormones like epinephrine and angiotensin II.
What are vasodilators released by endothelial cells?
Nitric oxide (vasodilator) and endothelin (vasoconstrictor).
How does exchange occur at capillaries?
Mainly by diffusion and bulk flow (filtration from capillaries; reabsorption back into them).
What drives filtration and reabsorption?
Filtration: capillary hydrostatic pressure; Reabsorption: plasma osmotic pressure from proteins.
What mechanisms increase venous return?
Skeletal muscle pump, respiratory pump, sympathetic venoconstriction, and increased blood volume.
What factors affect blood pressure?
Cardiac output (CO), total peripheral resistance (TPR), blood volume, vessel elasticity, and viscosity.
What maintains blood pressure homeostasis?
Baroreceptor reflex (short-term via ANS) and hormones like RAAS, ANP, and ADH (long-term).
