Circulatory System Flashcards
Arteries
thick muscular walls
relatively small lumen
elastic tissue for stretch and recoil - maintains high pressure
endothelium is folded allowing more stretch
all carry oxygenated blood except from pulmonary arteries
renal artery
hepatic artery
pulmonary artery
aorta
Veins
wider lumen very little elastic and muscle tissue (lower pressure) valves prevent backflow blood flow helped by contracting muscles All carry deoxygenated except pulmonary veins hepatic (portal) vein renal vein vena cava pulmonary vein
Capillaries
one cell thick and very near cells in exchange tissues - short diffusion pathway
many of them = large surface area
Tissue Fluid formation
hydrostatic pressure at start of capillary bed is greater than in tissue fluid
fluid forced out of capillaries and into spaces around the cells forming tissue fluid
hydrostatic pressure in capillaries reduced at the venule end
increased conc. plasma proteins and fluid loss results in more negative water potential at the venule end than tissue fluid
TF water re enters the capillaries from tissue fluid at venule end
excess is drained into lymphatic system and is bypassed back into circulatory system