blood pressure and flow Flashcards
function of arteries
carry blood away from the heart
pressure reservoirs
rapid transit passageway to organs
what do the arteries contain and their functions
extracellular collagen and elastin to withstand high pressures generated by the heart
smooth muscle cells to constrict and dilate to change resistance
how do arteries ensure smooth blood flow
the elastic tissues are stretched during systole and store pressure energy
this is returned to the blood during elastic recoil in systole and pushes it forward
function of the arterioles
they are major resistance vessels, have greater capacity to vasoconstrict and dilate to regulate blood flow and BP
how do arterioles differ in structure to arteries
they are a thick smooth muscle layer with little to no elastic tissue, much smaller radius
structure of capillary and how it relates to function
single layer of epithelial cells with fenestrations to facilitate exchange
extensive network to maximise diffusion through small distance and large SA
function of the veins
volume reservoir with a high capacity to stretch and store blood
venous return to the heart
what are veins made of
smooth muscle, elastin, fibrous connective tissue allowing stretch
where are valves found and their function
in veins to prevent back flow
what assists venous return
gravity-above the heart
skeletal muscle contraction- below the heart
define blood pressure
amount of force exerted by blood on the vessel wall
what is the pressure gradient
the difference in pressure between the beginning and end of the vessel
what does blood flow through vessels depend upon
pressure gradient and vascular resistance
what are the 3 starlings forces on a capillary
high BP at arterial end - squeezes out water and small solutes
osmotic pressure at venule end- pulls water back into capillaries
oncotic pressure- large proteins use osmosis to pull water back into capillary
