Boron Cardiac Physio Review II

Question 1

sinus arrhythmia

Answer 1

normal - with respiration

Question 2

re-entry

Answer 2

depolarization travels in circle

requires:
1 - closed conduction loop
2 - region of unidirectional block
3 - sufficiently slow conduction of APs around loop

**often with diverse tachyarrhythmias

Question 3

unidirectional block

Answer 3

impulses travel in one direction but not in the opposite one

Question 4

depolarization induced triggered activity

Answer 4

induced automaticity in non-pacemaer cells

I-Ca triggers slow positive deflection of Vm - early afterdepolarization

may trigger extrasystole

Question 5

run of three or more ventricular extrasystoles

Answer 5

pathologic

-V-tach?? compare to dubin

Question 6

long QT syndrome

Answer 6

prone to develop torsades de pointes

-hypokalemia, hypocalcemia, or medications

Question 7

Ca overload

Answer 7

digitalis intox

• SR sequesters too much Ca
• transient inward current - delayed afterdepolarization

-can produce spontaneous action potential

Question 8

ischemia and anoxia

Answer 8

decreased ATP

• ATP K channels more
• cells less excitable
• slow/blocks conduction

Question 9

myocardial infarction

Answer 9

peaking of T waves followed by T wave inversion

-then elevation of ST segment

Question 10

elevation of ST segment

Answer 10

myocytes at epicardium - become depolarized by cellular anoxic injury

• injured cell more positive resting potential
• but, has same plateau as uninjured cells
• difference in voltage is depressed everywhere but at the ST segment (elevates it)

Question 11

coronary artery spasm

Answer 11

also produce ST elevation

Question 12

ST segment depression and T wave inversion

Answer 12

ischemia

-anginal episodes

Question 13

deep Q waves

Answer 13

irreversible cell death (necrosis)

Question 14

AV valves

Answer 14

tricuspid (right)

mitral (left)

Question 15

semilunar valves

Answer 15

pulmonary (right)

aortic (left)

Question 16

four phases of cardiac cycle

Answer 16

1 inflow phase
2 isovolumetric contraction
3 outflow phase
4 isovolumetric relaxation

Question 17

systole

Answer 17

phase 2 and 3

isovolumetric contraction and outflow

Question 18

diastole

Answer 18

phase 4 and 1

isovolumetric relaxation and inflow

Question 19

dicrotic notch

Answer 19

when aortic valve closes

-dip in aortic pressure

Question 20

S1 heart sound

Answer 20

closure of AV valves

Question 21

S2 heart sound

Answer 21

closure of aortic and pulmonary valves

Question 22

S3 heart sound

Answer 22

diastolic filling gallop

Question 23

S4 heart sound

Answer 23

artial sound - presystolic gallop

Question 24

stroke volume = ?

Answer 24

EDV - ESV

Question 25

ejection fraction = ?

Answer 25

SV / EDV

Question 26

pressure-volume loop

Answer 26

plot of ventricular pressure and volume against time

Question 27

starlings law

Answer 27

longer muscle fiber causes more mechanical energy

-muscle length proportional to EDV

Question 28

contractility mesures

Answer 28

rate of pressure development

velocity of ejection

Question 29

enhanced contractility

Answer 29

increases stroke volume

Question 30

positive inotropic agents

Answer 30

increase Ca

• sympathetics
• cardiac glycosides (digitalis)
• high extracellular Ca
• low extracellular Na
• increased HR

Question 31

negative inotropic agents

Answer 31

decreased Ca

• Ca channel blockers
• low extracellular Ca
• high extracellular Na

Question 32

increased baroreceptor activity

Answer 32

inhibits the cardioacceleratory areas of medulla

Question 33

sympathetics to heart

Answer 33

increased heart rate and contractility

SA node, atria, and ventricles

**at rest - more PS

Question 34

parasympathetics to heart

Answer 34

decreases heart rate at SA
inhibit conduction through AV
also decreases contractility to some extent

Question 35

sympathetics in blood vessels

Answer 35

kidney and skin - vasoconstriction

Question 36

parasympathetics to blood vessels

Answer 36

sailvary and GI glands, erectile tissue

indirect vasodilation - NO

Question 37

sympathetics to blood vessels in skeletal m

Answer 37

vasodilation - cholinergic

vasoconstriction - adrenergic

Question 38

chromaffin cells

Answer 38

in adrenal medulla

-release epinephrine

Question 39

sympathetics in pacemaker cells

Answer 39

beta1

• stimulate If
• stimulate Ca current
• increased rate of diastolic depolarization and negative shift in threshold
• increased HR

Question 40

sympathetics in myocardial cells

Answer 40

beta1

• positive inotropic - contractility
• increased Ca channels

Question 41

parasympathetics in pacemaker cells

Answer 41

• M2 - open K channels - more negative max diastolic potential
• decreases I-f
• decreases I-Ca - reduced rate of diastolic depolarization

reduced heart rate

Question 42

parasympathetics in myocardial cells

Answer 42

minor negative inotropic effect

• counter adrenergic
• raising Ca - NO - inhibit L-type channels - decreased Ca influx

Question 43

alpha1

Answer 43

vasoconstriction

Question 44

beta2

Answer 44

vasodilation

Question 45

afterload

Answer 45

force against which ventricles eject blood

Question 46

preload

Answer 46

end-diastolic volume

Question 47

heart rate increases

Answer 47

diastole shortens greater extent than systole

-decreased EDV