cardiovascular blood vessels Flashcards
what are arteries
arteries carry blood away from the heart
what do arteries form eventually
capillaries
capillaries
tiniest blood vessels
function of capillaries
direct exchange of fluids with tissue cells, supplying nutrients and removing waste
vessel types
arteries
capillaries
veins
purpose of arteries design
high pressue design
what makes up arteries
tunica intima
tunica media
tunica externa
what is tunica intima made up of
endothelium
what is the lumen
a hollow area made from endothelium
clinical conditions that affect tunica intima
when conditions damage intima, it causes a release of chemicals from the endothelial cells that promote an inflammatory response with results like plaque and clotting
what makes up tunica media
smooth muscle cells and elastin sheets
function of tunica media
it is the autonomic nervous sys control of blood pressure
purpose of tunica externa
support
what is the tunica externa made of
supportive connective tissue, nerves
thick
arterial types
elastic
muscular
arterioles
what can elastic arteries do
stretch and recoil to absorb pulsating pressure
function of muscular arteries
distribute blood to different body and organ areas
when are muscular arteries most active
in vasoconstriction/vasodilation
blood pressure
what are arterioles made of
single layer of smooth muscle around the endothelium
how is the blood flow regulated to capillary beds
through neural, hormonal, and chemical signals
what is arteriosclerosis
hardening of arteries, which causes a decreased elasticity
result of arteriosclerosis
increased pressure damages smaller arterioles
increased ventricular effort
capillary types
continuous
fenestrated
sinusoidal
describe continous types
tight junctions between endothelial cells
few intercellular clefts for passage
ex of continous
blood brain barrier
blood brain barrier
chemical passage buffered through cell cytoplasm
describe fenestrated
small opening provide two way exchange with tissues
ex of fenestrated
hormone pickup
nutrient delivery
waste removal
describe sinusoidal
big gapes between endothelial cells permitting rapid interaction/flow between organ tissue cells and vessel contents
ex of sinusoidal
leaky capillaries of the liver, spleen, bone marrow where large proteins and blood cells can be easily exchanged between the blood and interstitial compartments
capillary beds
smallest vessels work as groups fed by arterioules then wind up as venules
what fine tunes organ blood to areas
sphincter valves
veins
low pressue, start small and get larger as they join and move blood toward the heart
venules
post capillary flow. very thin tunica media and externa allow fluid/ wbc exchange
how much of blood will form reservoir if needed
65%
what prevents back flow
venous valves
vericose veins
valves distort, leak, and swelling occurs in previous section of vein
what increases risk of vericose veins
long time standing, obesity, restricted venous return, stress of pregnance
where are vericose veins most common
lower limbs, abdomen
in anal, hemorrhoids
venous sinuses
enlarged area of endothelium but no tunics for collecting blood
ex of venous sinuses
dural sinuses
vascular anastomoses
arterial anastomoses
venous anastomoses
arterial anastomoses
arteries may divide to form smaller ones but recombine to increase supply to an area
venous anastomoses
veins normally combine to form larger ones but sometimes redivide to increase drainage from an area
blood flow formula
F=DELTA P / R
define blood flow= F
volume of blood flowing through a vessel, organ, or entire circulation
define blood pressure = P
force exerted on a vessel wall containing blood
define triangle symbol = DELTA P
if pressure changes, either up or down, it is written as triangle P
define resistance = R
opposition to flow and is a measure of the amount of friction blood encounters
what does peripheral resistance refer to
resistance away from the heart
what method do arteries, arterioles, capillary beds etc use to decrease R
vasodilate
