Chapter 20 Flashcards
Composed of simple squamous epithelium and releases substances to regulate contraction/relaxation of tunica media
tunica interna
used for vasodilation and vasoconstriction, made of smooth muscle
tunica media
made of areolar connective tissue, anchors to other structures
tunica externa
smaller tunica internal, thick tunica media, thin tunica externa
arteries
large tunica interna/lumen, thin tunica media, thick tunica externa
veins
largest arteries containing lots of elastin in tunica media, used to stretch and recoil
elastic arteries
Where are elastic arteries found?
aorta, pulmonary trunk, common carotid artery, subclavian artery, common iliac artery
medium sized arteries that distribute blood to certain body parts, used for vasodilation and vasoconstriction more smooth muscle
muscular arteries
Where are muscular arteries found?
most arteries
Smallest, think tunica media, always vasoconstrictor
arterioles
where are arterioles found?
off of muscular arteries
term for always vasoconstricted
vasomotor tone
smallest veins; companion vessel to arterioles, drains capillaries
venules
malfunction in valve of vein, blood pools up
varicose veins
companion vessels to muscular arteries, most have valves that dump blood to large veins
medium veins
companion to elastic arteries, most don’t have valves because they’re near the heart; act as blood reservoirs
large veins
connect arterioles to venules, optimal for exchange of substances between blood and body tissue
capillaries
What is the lining of continuous capillaries?
simple squamous epithelium
what is the basement membrane of continuous capillaries?
have small gap junctions called intercellular clefts
allows small solute movement
intercellular clefts
where are continuous capillaries found in?
capillaries within muscle, CNS, skin, thymus, lungs
Thin areas on endothelial layer called fenestrations which allow plasma proteins and small solutes to pass through
fenestrated capillaries
Where are fenestrated capillaries found?
small intestine, ciliary process, choroid plexus, kidney, endocrine glands
Have large openings between them, incomplete layer which allows for passage of large solutes
Sinusoids
Where are sinusoids located?
red bone marrow, liver, spleen, adrenal gland, parathyroid gland
contract and relax involuntarily in capillary bed
precapillary sphincter
Pressure of fluid on wall on capillary
hydrostatic pressure
What pulls water towards higher concentration of solute in capillary bed
osmotic pressure
Difference between osmotic and hydrostatic pressure
Net filtration rate
What are vasodilators caused from?
high CO2 low nutrients
Substances that dilate arterioles and relaxation of precapillary sphincter
vasodilator
force of blood against the inner walls of blood vessels
blood pressure
substances that constrict arterioles and contract precapillary sphincters, decrease blood flow
vasoconstrictors
highest blood pressure
arterial blood pressure
maximum pressure on blood vessel wall; arteries stretch
systolic pressure
minimum pressure on blood vessel wall; arteries recoil
diastolic pressure
net pressure created by the heart each time it contracts; only arteries; measures stretch and recoil capabilities
pulse pressure
how do you find pulse pressure?
systolic - diastolic pressure
average blood pressure within arterial system; makes sure tissues are adequately perfused
mean arterial pressure
change in blood pressure from 1 end of the BV to another end
BP gradient
no pulses of blood, pressure lowered compared to arteries, pressure drops more when moving through capillary bed
Capillary blood pressure
pressure is very low b/c walls of veins are thinner, little stretch/recoil
venous blood pressure
rate of blood flow back to the heart
venous return
pump within limbs that when muscles contract, blood moves up from legs and arms to abdominopelvic area
skeletal muscle pump
What are the 2 pumps that assist in venous return?
skeletal muscle, respiratory
Pump within thoracic cavity
respiratory pump
Decreases pressure and moves blood to thoracic cavity
inhale
increases pressure and moves blood into heart
exhale
amount of friction the blood experiences as it is transported through blood vessels
resistance
opposition to flow that blood encounters in vessels
peripheral resistance
What are 3 factors that affect resistance?
blood viscosity, blood vessel length and radius
What happens to resistance if blood viscosity is thick? thin?
thick=more
thin=less
What happens to resistance of vessel length is longer?
more resistance
What happens to resistance of blood vessel diameter is small? large?
small=more
large=less
increase cardiac output = MAP ____
increase
Vessel diameter increase = MAP _____
increase
resistance decreases = _____ blood flow
increase
Where is the cardiovascular center located?
medulla oblongata
Stretch receptors change, changes AP frequency
baroreceptors
how much stretch in aortic arch
aortic arch baroreceptors
how much stretch in internal carotid artery
carotid baroreceptors
regulate heart activity (cardiac output)
cardiac center
Affects the myocardium and SA node to increase heart rate
sympathetic nerve activity
affect SA node and AV node to decrease heart rate
Parasympathetic activity
regulates the degree of vasoconstriction and vasodilation of blood vessels
Vasomotor center
What hormones increase blood pressure?
epinephrine and norepinephrine
What is norepinephrine and epinephrine stimulated by?
Sympathetic nervous system
increase in stretch= ___ action potentials
more
decrease in stretch = ____ action potentials
less
