heart valves and cardiac cycle + pace makers and action potentials

Question 1

S1 sound is closure of which valves

Answer 1

AV valves (Tricuspid and mitral)

Question 2

S2 sound is closure of

Answer 2

aortic and pulmonic valves

Question 3

S3 occurs when in diastole and why

Answer 3

early, from a sudden deceleration of blood flow into left ventricle from the left atrium

Question 4

S4 late or early in diastole

Answer 4

late diastole,
Occurs in ventricular non-compliance

Question 5

stenosis = late in diastole
regurgitation = early in diastole

both are characterized by

Answer 5

stenosis = narrowing/thinning of the valves

regurgitation = valve can not close properly, allowing for blood flow

Question 6

stroke volume =

Answer 6

volume of blood pumped out of the L ventricle during systolic cardiac contraction

Question 7

3 factors that affect stroke volume

Answer 7

contractility, afterload, and preload

increase with contractility and preload

decrease with afterload

Question 8

Which ions increase contractility (SV)

Answer 8

o Catecholamine stimulation via B1 receptor (-> Ca2+ release)
o Intracellular [Ca2+]
o Intracellular [Na+] (due to activity of Na+/Ca2+ exchanger)

Question 9

Contractility decreases with

Answer 9

o Extracellular [Na+] (due to activity of Na+/Ca2+ exchanger)
o B1-blockade
o HF with systolic dysfunction
o Acidosis
o Hypoxemia/hypercapnia

Question 10

preload depends on which 2 factors

Answer 10

venous tone
circulating volume

Question 11

afterload depends on which 2 things

Answer 11

wall tension (more wall tension = more afterload)

hypertension

Question 12

myocardial oxygen demand depends on: contractility, afterload, and what else (2 more)

Answer 12

HR
Ventricular wall tension

Question 13

cardiac output =

Answer 13

= SV + HR

Question 14

name the phases of the cardiac cell cycle (7)

Answer 14

1. Atrial contraction
   Systole
2. Isovolumetric contraction
3. Rapid ventricular ejection
4. Reduced ventricular ejection
   Diastole
5. Isovolumetric ventricular relaxation
6. Rapid ventricular filling
7. Reduced ventricular filling

Question 15

atrial contraction = SA node or AV node firing

Answer 15

starts with SA node firing

Question 16

atrial contraction = which wave on ECG

Answer 16

P wave

Question 17

atrial contraction = contraction of both L and R atria T or F

Answer 17

T

Question 18

Isovolumetric Contraction on the ECG

Answer 18

QRS complex

Question 19

Isovolumetric Contraction: ventricle pressure exceed or decrease compared to atria

Answer 19

exceed pressure in the atria

Question 20

why is blood volume constant in the ventricles during Isovolumetric Contraction

Answer 20

the AV valves and the semilunar valves are closed, so the blood volume within the ventricles stay the same

Question 21

rapid ventricular ejection = semilunar valves open

explain why (pressure in the Ventricle, aorata, and pulmonary artery

Answer 21

pressure in the ventricles exceed the pressure in the aorta and pulmonary arteries, so the semilunar valves open

Question 22

sudden ejection of blood from the ventricles also known as what stage of cardiac cycle

Answer 22

rapid ventricular ejection

Question 23

Reduced ventricular ejection corresponds with what on ECG

Answer 23

T wave

Question 24

how does reduced ventricular ejection differ from RAPID ventricular ejection

Answer 24

blood outflow in reduced is not due to contraction BUT inertial energy of the blood

so blood moves out at a slower rate

Question 25

during ventricular diastole does aortic valve or pulmonary valve close first

Answer 25

aortic valve closes first

Question 26

ventricular diastole = which wave on ECG

Answer 26

END of T wave

Question 27

dicrotic notch is caused by

Answer 27

a fall in the aortic pressure, bc Blood starts to flow back from the aorta to the ventricles due to the fall in pressure in the ventricles

Question 28

in Isovolumetric ventricular relaxation which valves are open

Answer 28

NONE ISOvolumetric = valves are always shut

Question 29

in Rapid ventricular filling explain pressure bw atria and ventricles

Answer 29

the atrial pressure exceeds the ventricular pressure

Question 30

when (stage of cardiac cycle) would you likely hear S3 sounds

Answer 30

Rapid ventricular filling due to volume overload or ventricular dilation

Question 31

explain Reduced ventricular filling

Answer 31

Most of the blood in the ventricles comes from passive filling (before the atria contract)

Question 32

what are pacemaker cells

Answer 32

cardiac cells that can spontaneously create action potentials

Question 33

SA node a primary or latent pacemaker cell?

Answer 33

primary (only primary pacemaker)

Question 34

SA node rate = 60-100bpm AV node = ?

Answer 34

40-60bpm

Question 35

why is it important that the AV node depolarize slower than SA node

Answer 35

bc it allows ventricles to contract after filling with blood

Question 36

location of bundle of His

Answer 36

through septum bw ventricles - dividing into L and R branches

Question 37

do Purkinje fibers depolarize slowly or rapidly to assure that both ventricles contract at the same time

Answer 37

rapidly

Question 38

bundle of His and Purkinje fibers bpm =

Answer 38

40-60bpm

Question 39

Action Potential Phases in Pacemaker Cells (three phases)

Answer 39

(phase 4): Slow depolarization (phase 0) Rapid depolarization (phase 3) Repolarization

Question 40

explain Slow depolarization

Answer 40

1. (phase 4) Slow depolarization - sodium moves into cell through channels that open in response to hyperpolarization, and slowly depolarizes cell until threshold potential is met

Question 41

explain (phase 0) Rapid depolarization

Answer 41

strong inward calcium current, responsible for rapid depolarization

Question 42

explain (phase 3) Repolarization

Answer 42

strong potassium current moves out of cell; responsible for repolarization

Question 43

which law: the greater the diastolic filling (preload), the greater the quantity of blood pumped (stroke volume)

Answer 43

Frank-Starling Law more preload= greater stroke volume