BLOOD VESSELS Flashcards
primary site of action of vasoactive agents
post-capillary venules
vasoactive agents
histamine, serotonin
what tunica is thickest in veins
tunica externa/adventitia
what % of blood in veins at any time
65-70%
blood reservoir
veins, spleen, liver, bone marrow, skin
what does sympathetic input do to veins
vasoconstriction; moves blood out of reservoir into arteries
which tunica is thickest in muscular artery
tunica media (many SMCs)
T or F: BP in veins is too low to overcome gravity
T
what forms venous valves
infolding of tunica intimacy
where can you find venous valves
veins of lower limbs
function of valves
prevent backflow
what forces venous blood against gravity
contraction of adjacent skeletal muscles
T or F: there is huge vascular resistance in capillaries
T; very small diameter
valves open when P is…
higher below
valves close when P is…
higher above
varicose veins
veins enlarge in diameter, valves can’t touch, blood pools in these veins
core of valves
sub endothelial CT
deep vs superficial veins: arteries
deep veins have accompanying systemic arteries; superficial veins (subcutaneous) don’t have accompanying arteries
temperature regulation
shunting blood between deep and superficial veins
what route back to the RA will blood take if you’re hot
superficial; throw off heat (red skin)
what side has brachiocephalic trunk
right
how many branches of aorta supply head, neck, arms
3 (brachiocephalic trunk, left common carotid, left subclavian)
which part of the descending aorta is NOT paired
visceral branches in abdominal aorta
what do the unpaired arteries in the abdomen supply
digestive tract (think: 1 for 1 long tube)
what divides the thoracic and abdominal descending artery
diaphragm
what arteries supply the legs
R and L external iliac arteries
what arteries supply kidney
paired abdominal parietal (contained in body wall)
T or F: all veins are paired in parietal and visceral
T; all paired to drain body wall and contained organs
major vein draining into IVC
hepatic vein; from liver (and blood from intestines)
name of system that drains stomach, intestinal blood
hepatic portal system
how many hepatic veins drain into IVC
usually 3
T or F: there is a vein to drain the stomach (gastric vein)
F; goes through liver
T or F: only the arterial system has brachiocephalic trunk
T; in venous its not called trunk; but has 2 brachiocephalic veins
arteries
carry blood Away from heart
right side of heart -> ____ circulation
pulmonary
left side of heart -> ____ circulation
systemic
is circulation in parallel or series
parallel
circulatory system is delivery system except at
capillaries
T or F: arteries always carry oxygenated blood
F; not in pulmonary arteries (deoxygenated away from heart)
4 functions of tunica intima
selectively permeable barrier
nonthrombogenic (makes anticoagulants; thromobomodulin, TPA)
modulates vascular resistance (NO, ACE release; but acts on media)
regulate immune response (leukocyte adhesion)
what branch of NS innervates tunica media
sympathetic
what layer has vaso vasorum
adventitia
T or F: sympathetic innervation of tunica media always causes constriction
F; dilation to skeletal muscles, heart; constrict to skin (pale)
branches of aorta that are elastic arteries
brachiocephalic trunk, common carotids, subclavian, common iliac
what tunica has elastin in elastic arteries
media
form of elastin in elastic arteries
fenestrated sheets
T or F: you can see elastic laminas in elastic arteries
F; inconspicuous
how do elastic arteries modulates BP
lower systole, bump up diastole
what produces elastin in elastic arteries
SMCs
examples of muscular arteries
gastric, renal, skeletal muscle
do muscular arteries have IEL and EEL
Yes; prominent
how many layers of SMCs in small arteries
3-6
how many layers of SMC in arterioles
1-2
what vessels change resistance to control BF into capillaries
arterioles
composition of capillaries
endothelium + BM
T or F: capillaries may have smaller diameter than RBC
T; RBC may bend
what cells contribute to capillary repair
pericytes
3 types of capillaries
continuous, fenestrated, sinusoids
what type of capillary in lung, brain, muscle
continuous
what junctions in continuous capillaries
desmosomes, tight junctions
continuous capillaries: transport method
transcytosis
where can you find fenestrated capillaries
endocrine, small intestine, choroid plexus, kidney
function of fenestrae
rapid exchange of small proteins
how do fenestra form
pinocytotic vesicles span membrane
T or F: fenestrae are dynamic
T; number & size change with activity
BM in sinusoids
discontinuous
function of sinusoids
rapid exchange of large solutes
where would you find sinusoids
liver, spleen, bone marrow, lymph nodes
function of large diameter in sinusoids
slows BF, more time for molecular exchange
function of arteriovenous anastomosis
shunt blood from A to V; skip capillary bed
where would you find arteriovenous anastomoses
skin, erectile tissue
what is used in precapillary sphincter to adjust flow
SMCs
what channel provides direct route from arteriole to venule
met arteriole/ throughfare channel
circulating ___ provides sympathetic input
epinephrine, norepinephrine
where does epinephrine come from
adrenal glands
what 2 molecules vasodilation
NO, CO2
what tunica controls resistance
media; contraction/relaxation of SMCs
