2 week 11

Question 1

blood pressure/MAP = ___ x ___

Answer 1

cardiac output x peripheral resistance

Question 2

what happens to MAP when you increase CO?

Answer 2

MAP increases when TPR remains constant

Question 3

what happens to MAP when CO remains constant?

Answer 3

MAP increases if TPR increases

Question 4

whats Ohm’s law?

Answer 4

small decrease in BP = big decrease in CO = increase in peripheral resistance (HEART FAILURE)

Question 5

diff bw venous pressure and central venous pressure?

Answer 5

VP: average VP within venous compartment

CVP: pressure in thoracic vena cava (near right atrium)

Question 6

how does the skeletal muscle pump increase CVP?

Answer 6

• alternate contraction and relaxing, muscles act as pumps that help drive blood toward the central veins
• ex, when contract, distal valves close and proximal valves open, so blood flows to heart. when relax, distal valves open and proximal valves close, so blood moves away from heart.

Question 6

how does the respiratory pump increase CVP?

Answer 6

• inhale: diaphragm down, rib cage expands. blood moves from abdomen (high pressure) to chest (low pressure) and fills heart.
• exhale: pressure gradient reverses, but reverse flow is prevented by valves in abdominal veins. since chest = higher pressure than right atrium, blood enters heart.

Question 7

how does blood volume contribute to MAP?

Answer 7

• blood volume determined by fluid intake/fluid loss.
• fluid loss can be passive or regulated at kidneys.
• +fluid intake = +blood volume = +blood pressure

Question 8

describe fast vs slow response to HIGH blood volume/pressure.

Answer 8

fast: cardiovascular system vasodilates to decrease CO.

slow: kidneys produce more urine to decrease blood volume.

Question 9

describe short vs long term response to LOW blood volume/pressure.

Answer 9

short: baroreflex increases sympa activity to increase CO and TPR.

long: vasoconstriction of kidney vessel stops urine production to increase blood volume/pressure.

Question 10

what is orthostatic hypotension? what is it caused by?

Answer 10

• drop in BP upon standing → dizziness
• caused by venous pooling (which lowers CVP and MAP)

Question 11

what do veins do to increase CVP?

Answer 11

• reserve volume by being highly compliant (vasoconstricting!)

Question 12

how does fluid flow across the capillary wall?

Answer 12

• from arteriole to venule.
• hydrostatic pressure = forces fluid OUT (filtration, BP) and decreases as move from arteriole to venule.
• oncotic pressure = forces fluid back IN (absorption, dilute protein) and remain constant.
• see slide 20

Question 13

what happens to the ~3L of fluid leaks out of the capillaries each day, moves into the extracellular space?

Answer 13

taken up by lymphatic system (eventually return to right atrium)

Question 14

how do barorecpetors measure increases in pressure?

Answer 14

• action potentials
• increased pressure = increased AP frequency

Question 15

T or F: baroreceptors connect to the CNS?

Answer 15

true! medulla > cerebral cortex > outflow via parasympa system > SA node to moderate heart rate

Question 16

if BP is low, ___ activity increases.

if BP is high, ___ activity increases.

Answer 16

sympa

parasympa

Question 17

what does increased metabolic rate do for vascular resistance?

Answer 17

• oxygen gets consumed faster (concentration decreases in extracellular fluid)
• arterioles vasodilate to increase blood flow and oxygen delivery
• INTRINSIC

Question 18

what does decreased blood flow do for vascular resistance?

Answer 18

• CO2 removal rates drop (concentration increases in extracellular fluid)
• arterioles vasodilate to increase blood flow and CO2 removal
• INTRINSIC

Question 19

what does exercise do to blood flow, CO, heart rate, SV, MAP, and TPR?

Answer 19

• +blood flow, +CO, +heart rate, +SV
• small +MAP because -TPR due to vasodilation

Question 20

what is ischemic heart disease?

Answer 20

build up of plaque leading to low blood flow and imbalance between the supply of oxygen and the myocardial demand

Question 21

diff bw ischemic and hemorrhagic strokes?

Answer 21

• ischemic = build up of plaque or clot
• hemorrhagic stroke = burst of blood vessels, blood accumulates in brain leading to constriction

Question 22

what do cholesterol lowering drugs do to cholesterol?

Answer 22

allow it to be excreted via feces

Question 23

T or F: high LDL cholesterol = low # of events

Answer 23

false – high = high events (and vice versa)

Question 24

what are atherosclerotic plaques? diff bw stable and unstable plaques?

Answer 24

• atherosclerotic plaques = fat buildup bw muscle and endothelial layer of blood vessels
• stable = THICK cap protecting it… less likely to rupture until blood vessel is squeezed shut, leading to stroke/heart attack.
• unstable = THIN cap protecting it… can lead to rupture, fat spills into blood vessel leading to clog that can cause strokes/heart attack.

Question 25

physiological signs of heart attack? (3)

Answer 25

1. chest pain
2. ST elevation (heart cannot repolarize)
3. myocardial enzyme elevation (creatine kinase and troponin)

Question 26

what is an angioplasty?

Answer 26

injection of catheter into coronary arteries (and inject dye to see blood flow)

Question 27

what is a coronary artery stent/bypass graft?

Answer 27

• stent = balloon catheter
• graft = take vein from leg and attach bw aorta + coronary arteries, bypassing blocked vessels

Question 28

T or F: in heart failure, the left ventricle becomes dilated and thin.

Answer 28

true!

Question 29

problem with heart transplants and artificial hearts?

Answer 29

only one cardiac output

Question 30

cardiac rehab reduces risk of all-cause mortality by __% and cardiac mortality by __%

Answer 30

27
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