Exam 4: Chapter 15 Flashcards
what four things are blood vessels composed of?
endothelium
elastic tissue
smooth muscle
fibrous tissue
what are arteries composed of?
all four!!
-most elastic vessel
-thickest wall
what are arterioles composed of?
endothelium & smooth muscle
what are capillaries composed of?
single layer of endothelium
-sits on top of basal lamina
what are venules composed of?
endothelium & fibrous tissue
what are veins composed of?
all four!!
which of the four vessels is known as a volume reservior?
veins
-holds more than 1/2 of the bodies blood
which of the four vessels is known as a pressure reservoir?
arteries
-can stretch & eject blood
which vessel has the thickest wall?
arteries
which vessel is the main site of regulation? how is it regulated?
arterioles
-vasoconstriction & vasodilation
-contains a precapillary sphincter
what does a precapilary sphincter do?
control movement in & out of capillary beds
-helps change diameter
-OPEN: increase blood amount (blood goes to capillaries)
-CLOSED: decrease blood amount (blood goes to venous system)
which vessel has the smallest diameter?
capillaries
which vessel has the lowest velocity?
capillaries
which vessel contains pericytes? what are they?
capillaries
-contractile cells that surround capillaries to control leakiness
-more pericytes = less leaky
which vessel contains valves to ensure 1-way flow?
veins
which vessel has the lowest pressure?
veins
which vessel makes up the majority of vessels in the body?
veins
what is angiogenesis?
synthesis of new blood vessels
-wound healing, uterine lining
-occurs in malignant tumors
what is blood pressure?
how strong blood moves through vessels
how blood pressure created?
through ventricular contraction
-semilunar valves open and eject blood into arteries
-arteries expand and store pressure in elastic walls, then recoils
what is systolic pressure?
TOP (120)
-aortic pressure during ventricular contraction
what is diastolic pressure?
BOTTOM (80)
-aortic pressure during ventricular relaxation
how is BP measured?
sphygmomanometer
-cuts off blood flow & then released to make an aggressive flow
-first set of noise = systolic pressure
-silence after noise = diastolic pressure
what is pulse?
how many times the heart beats
-ventricular ejection
what is the equation for pulse pressure?
systole - diastole
EX: 120-80 = 40mmHg
what is considered hypotension?
less than 90/60
what is considered hypertension?
over 140/90
what is arteriole pressure?
driving pressure for blood flow
what is the equation for MAP?
diastole + 1/3 (pulse pressure)
EX: 80 + 1/3 (40) = 93.3mmHg
what is MAP proportional to?
CO & R
should MAP be closer to a systolic pressure or diastolic pressure?
diastolic
-longer period of relaxation than contraction
as blood volume increases, what happens to BP?
BP increases
how to you compensate when BP is high?
vasodilation
-decreases R
-decreases MAP
-decreases BP
decrease CO
-decreases HR & SV
-decreases MAP
-decreases BP
what organ regulates BP?
kidneys
-more water will decrease BP
is there more kidney excretion or reabsorption when BP is high?
excretion
-get rid of excess water
what three things are considered vasoconstrictors?
NE (alpha receptors)
vasopressin
angiotensin 2 (AGT2)
what five things are considered vasodilators?
E (beta2 receptors)
NO
low O2 (high CO2, high K+, high H+)
histamine
natriuretic peptides (ANP)
what does myogenic autoregulation do?
adjusts blood flow in smooth muscle w/o any outside influences
-it can do it on it’s own
what are the steps of myogenic autoregulation?
- increase BP
- increase stretch
- activate mechanoreceptors (cation channels)
- depolarization
- opens Ca2+ channels, Ca2+ enters from ECF and SR
- Ca2+ binds calmodulin
- activate myosin light chains
- muscle contracts -> vasoconstriction
what is active hyperemia?
increased blood flow due to increases metabolism
-tissues are more active due to vasodilation
what is reactive hyperemia?
increased blood flow due to occlusion (blockage)
-causes vasodilators to activate
why is blood flow altered?
so blood goes to organs in higher metabolic need
how are arterioles arranged?
parallel
what is arteriole flow dependent on?
resistance
-if one has more resistance, blood is shunted to the other
if the heart works harder, what happens to coronary flow?
coronary flow increases
what happens when O2 is low in the body?
vasodilators activate to decrease R = increase blood flow
what are baroreceptors?
-mechanoreceptor
-tonically active
-found in the carotid arteries and aorta
what is the CVCC?
in the medulla oblongata
-control center in CNS that controls BP
what is the baroreceptor reflex when BP is decreasing?
- decreasing BP
- decrease firing rate of baroreceptor
- sensory neurons
- CVCC
- increase SYMP (alpha receptors, vasoconstriction)
- decrease PARASYMP
- overall increase in BP
what happens when BP is decreasing and one arteriole is constricted but we want to keep it constricted?
we can change a single variable
-changing CO will bring the BP back to normal without altering resistance
what is orthostatic hypotension?
occurs when you go from a lying position to a standing position
-BP decreases due to a redistribution of blood in the body
-triggers baroreceptor reflex
-extensive bedrest can make the reflex less effective
what happens the amount of capillaries when theres an increases metabolic activity?
more capillaries
what are continuous capillaries?
MAJORITY
-have small pores
-passes solutes, gases, glucose
-does NOT pass proteins, cells
what are fenestrated capillaries?
-have medium size pores
-more fluid can pass through
-found in kidneys and small intestine
what are sinusoid capillaries?
-have large pores
-proteins and cells can pass
-found in bone marrow, liver, spleen
why do capillaries have the lowest velocity?
due to the several branches that creates a larger area
-allows for easier diffusion
what is diffusion?
moves small solutes
-bigger the conc. gradient = faster diffusion
what is transcytosis?
moves large solutes
-uses vesicular transports
what is bulk flow?
movement of fluid due to hydrostatic and osmotic pressure
what is hydrostatic pressure? (P(H))
pressure exerting on walls
-POSITIVE net pressure
what is colloid osmotic pressure? (pie)
plasma proteins in capillaries
-NEGATIVE net pressure
which one, hydrostatic or osmotic pressure, does filtration?
hydrostatic pressure
-flow OUT of capillary
-higher at arterial end
-usually larger
which one, hydrostatic or osmotic pressure, does absorption?
colloid osmotic pressure
-flow INTO capillary
-higher at venous end
-attracts water
-constant at both ends!!!
what does the lymphatic system do for the circulatory system?
returns fluid that is lost at capillaries
-contains white blood cells
what is lymph?
no RBC
-fluid
what are lymph nodes?
collections of white blood cells
-start immune response
what is atherosclerosis?
elevated cholesterol (not water soluble)
-must be combined with lipoproteins to be in the body
what is HDL-C?
GOOD
-decreases atherosclerosis
-removes LDL-C
what is LDL-C?
BAD
-accumulates b/w endothelium and other layers
-turns into plaque in the vessels = occlusion
what is primary hypertension?
no clear cause
-genetic
what is secondary hypertension?
due to another dysfunction in the body (kidney, endocrine)
what does hypertension do to the body?
increases afterload to overall increase BP
what are four ways you can treat hypertension?
block AGT2
block Ca2+ channels
diuretics (more excretion)
beta blockers
