physio - vasculature

endothelium, elastic tissue, smooth muscle, fibrous connective tissue

the 4 layers of blood vessel structure

endothelium (material of blood vessel)

thin single layer of epithelial cells on basement membrane

elastic tissue (material of blood vesel)

has elastin protein; allows for stretch

smooth muscle (material of blood vessel)

contract or relax to control vessel diameter

fibrous connective tissue (material of blood vessel)

has collagen protein, tensile strength, is durable

elastic arteries

aorta, pulmonary arteries, major aorta branches are examples of ______

elastic arteries

act as “pressure reservoir” - can store and release pressure; stretch when ventricles contract and recoil when ventricles relax

muscular arteries

thick layer of smooth muscle, which allows for vasodilation and vasoconstriction; deliver blood to organs

arterioles

“little arteries” with a smooth muscle layer, precapillary sphincters contract to direct capillary bed flow (_____ are at the top of capillary bed)

capillaries

smallest vessels in body; passage of single red blood cell; they are exchange sites

continuous, fenestrated, sinusoid

3 types of capillaries

continuous (capillary type)

have leaky junctions between endothelial cells; most common in body; paracellular movement

fenestrated (type of capillary)

have large pores/fenestrations; kidney, small intestine

sinusoid (type of capillary)

very large pores; most permeable; proteins and even cells can pass through (bone marrow, spleen, liver)

bulk flow

large number of molecules move in the same direction; passive process; involves pressure differentials

hydrostatic pressure (PH)

pressure exerted by fluid in vessel

colloid osmotic pressure (π)

pressure due to colloidal suspension of molecules in blood

Starling forces

hydrostatic pressure and colloid osmotic pressure

P_H > π

net filtration occurs; net fluid exit

P_H < π

net absorption occurs; net fluid entry

lymphatics

excess filtered fluid moves into _______

larger

lymphatic capillary is ______ than blood capillary

endothelial cells of lymphatic capillary

_____ have overlapping ends which makes them more permeable than blood capillary

bulk flow

capillary exchange occurs via ______

lymphatic vessels

lymphatic capillaries connect to ______

vascular tone

smooth muscle in a state of partial contraction

vasoconstriction

decrease diameter

vasodilation

increase diameter 

systolic

highest pressure in arteries during ventricular systole

diastolic

lowest pressure in arteries during ventricular diastolep

pulse

traveling pressure wave

sympathetic innervation

most blood flow control by ________

systemic veins and venules (blood reservoirs)

at any given time, most blood is here

compliance (ability of hollow organ to stretch)

veins have high _______

skeletal muscle pump

muscle contractions compress vessels and promote flow

venous valves (skeletal muscle)

flap-like cusps comprised of endothelium and connective tissue

respiratory pump

pressure changes promote flow (inhale - diaphragm moves down, decrease thoracic pressure and increase abdominal pressure; flow moves toward thoracic cavity)

baroreceptors

Mean arterial pressure is monitored by _______ in aorta and other arteriesB

Baroreceptor reflex

know baroreceptor reflex

increased

increase blood pressure leads to _______ firing of baroreceptors in carotid arteries and aorta; lowering sympathetic output (lowering heart rate, force of contraction, etc.) and lowering blood pressure

decreased

decreased blood pressure leads to ________ firing of baroreceptors in carotid arteries and aorta; increasing sympathetic output (increase heart rate, force of contraction, etc.) and increasing blood pressure