Boron Cardiac Physio Review

Question 1

resistance in series

Answer 1

R + R + R

blood flow in given organ

• single artery supplies organ
• goes to ateries > arterioles > capillaries > veins

Question 2

resistance in parallel

Answer 2

1/R + 1/R + 1/R

systemic circulation
-arteries that branch off aorta to organs

Question 3

three kinds of pressure in circulation

Answer 3

1 driving pressure - axial
2 transmural pressure - radial - intravascular vs. tissue pressure
3 hydrostatic pressure - gravity on column of fluid

Question 4

CO = ?

Answer 4

HR x SV

Question 5

poiseuilles law

Answer 5

flow = deltaP x r^4 / 8nl

r  = radius
n = viscosity
l = length of vessel

flow directly proportional to pressure difference and inversely to radius of vessel to the fourth and inversely to length and viscosity

Question 6

reynolds number

Answer 6

determines when blood flow becomes turbulent

• laminar below 2000
• turbulent above 3000

Question 7

increases in reynolds number

Answer 7

**more turbulent flow

decreased blood viscosity - decreased hematocrit, anemia

increased blood velocity - narrow vessel

also increased vessel diameter

Question 8

pulse pressure

Answer 8

difference between SBP and DBP

Question 9

four factors generating presure in circulation

Answer 9

1 - gravity
2 - compliance of vessels
3 - viscous resistance
4 - inertia

Question 10

gravity

Answer 10

P difference when difference in height

-ex/ when patient standing

Question 11

standing pressure

Answer 11

high in feet
reference at heart
low in head

Question 12

driving pressure when standing?

Answer 12

remains the same in head and heart

• difference between SBP and DBP
• slightly higher at heart

Question 13

gravity does not affect

Answer 13

driving pressure that governs flow

Question 14

palpatory method of BP

Answer 14

radial artery at wrist

-systolic ONLY

Question 15

auscultatory method of BP

Answer 15

systolic and diastolic

Question 16

fick principle

Answer 16

allows you to measure CO

CO = O2 consumption / O2 arteries - O2 veins

Question 17

highest cross sectional area

Answer 17

capillaries

Question 18

slowest velocity of blood

Answer 18

capillaries

Question 19

blood volume distribution

Answer 19

20% systemic arterial
65% systemic venous
10% pulmonary
5% heart chambers

Question 20

arteries

Answer 20

resistance vessels

Question 21

veins

Answer 21

volume reservoirs

-capacitance vessels

Question 22

compliance

Answer 22

distensibility of blood vessels
-greater in veins (if low pressure)

-change in volume with change in pressure

Question 23

veins at “arterial pressure”

Answer 23

not as compliant
-sudden increase in volume leads to large increase in transmural pressure

case with saphenous vein in CABG

Question 24

transmural pressure

Answer 24

distending force - increases circumference of vessel

Question 25

laplaces law

Answer 25

describe how tension in vessel wall increases with transmural pressure -for given transmural pressure - wall tension gets larger as radius increases

Question 26

convection

Answer 26

main mechanism for net transfer of fluid across capillary membrane determined by hydrostatic pressure and colloid osmotic pressure starling equation used

Question 27

standing

Answer 27

increased capillary pressure - due to increased hydrostatic forces -results in edema

Question 28

pulmonary edema

Answer 28

pulmonary HTN - increased hyrostatic pressure -with left-sided heart failure

Question 29

nephrotic syndrome

Answer 29

loss of protein | -decreased plasma colloid oncotic pressure - edema

Question 30

pregnancy

Answer 30

plasma protein synthesis too slow | -decreased plasma colloid oncotic pressure - edema

Question 31

during ischemia

Answer 31

blood vessels deteriorate | -with reperfusion - local edema

Question 32

lymph flow

Answer 32

dependent on interstitial pressure

Question 33

slow APs

Answer 33

SA and AV nodes

Question 34

fast APs

Answer 34

atrial myocytes purkinje fibers ventricular myocytes

Question 35

phase 0

Answer 35

upstroke - Ca slow - Na and Ca fast

Question 36

phase 1

Answer 36

rapid repolarization - inactivation of Na and Ca - activaiton of K

Question 37

phase 2

Answer 37

plateau phase | -Ca and Na

Question 38

Phase 3

Answer 38

repolarization | -K

Question 39

Phase 4

Answer 39

electrical diastolic phase - most negative - maxi diastolic potential - SA, AV nodes - changes in K, Ca, and F currents - produce pacemaker activity

Question 40

If

Answer 40

non-selective cation channels

Question 41

SA node phase 4

Answer 41

outward K inward I-f slight inward Ca

Question 42

SA node phase 0

Answer 42

depolarization | -calcium

Question 43

three ways to slow SA node

Answer 43

- decrease phase 4 steepness - max diastolic potential more negative - threshold more positive

Question 44

acetylcholine on SA and AV nodes

Answer 44

PS activity -slows pacemaker - all three mechanisms 1 - decreases If - reduces phase 4 steepness 2 - opens GIRK channels - increasing K conductance - making maximum diastolic potential more negative 3 - reduces I-Ca in SA node - reduces steepness of phase 4 and moves threshold more positive

Question 45

ACh on AV node

Answer 45

not usually the pacemaker -PS innervation slows conduction velocity -inhibition of I-Ca that makes threshold more positive

Question 46

sympathetics on heart

Answer 46

increase heart rate - increase I-f in nodal cells - increase phase 4 steepness - increase I-Ca - steepens phase 4 depolarization and makes threshold more negative **no large change in maximum diastolic potential

Question 47

sympathetics in heart muscle

Answer 47

atria and ventricles - positive inotropic - contraction - 4 ways 1 - increased I-Ca - more Ca in muscle cell - greater Ca induced Ca release 2 - increase sensitivity of SR Ca release channel to cytoplasmic Ca 3 - enhance Ca pumping into SR - stimulate SERCA Ca pump 4 - increased I-Ca presents more Ca to SERCA - so SR Ca stores increase over time **all more Ca to troponin C - more forceful contraction