plasma
fluid medium of blood
hemoglobin
iron containing protein that carries oxygen
platelets
cell fragments that clot the blood
arteries
transport oxygenated blood
branch out to arterioles
veins
transport deoxygenated blood back to heart (along with waste products)
have valves to prevent backflow
capillaries
one cell thick
exchange points of nutrients and waste products
tunica adventitia
outer covering
connective tissue, collagen, elastic fibers
allow stretching for blood flow
tunica media
middle layer
thicker in arteries than veins
tunica intima
inner layer
elastic membrane lining and smooth endothelium
veins don’t have the elastic membrane and contain valves here
continuous capillaries
muscle, fat, nervous tissue
joined by tight non-permeable junctions
fenestrated capillaries
endocrine glands, kidneys
have intracellular perforations called fenestrae
discontinuous capillaries
liver, bone marrow
have open spaces between cells and are permeable to passage of blood cells
pericyte
a cell type which partially encircles most capillaries that shares a common membrane with endothelial cells
blood flow
measured in mL/min
equivalent to cardiac output
arteriosclerosis
hardening of arterial walls
systolic pressure
pressure at peak of ventricular CONTRACTION
diastolic pressure
pressure when ventricles are RELAXED
resistance to blood flow
changes in vessel diameter are the most important factor when measuring
if an organ needs to adjust its blood flow, cells surrounding the vessels release vasoactive substances that can either constrict or dilate the resistance vessels
mean arterial pressure
the average BP produced by the heart
