Ex2 L5 CVS

Question 1

Force the muscle can generate is dependent on

Answer 1

Length of muscle

Question 2

Optimal length of muscle

Answer 2

Resting length

Question 3

Bicep muscle is example of

Answer 3

Length-tension relationship

Question 4

Optimal length of cardiac muscle

Answer 4

The more stretched it is (more filled ventricle = more force)

Question 5

Cardiac muscles are physically coupled via

Answer 5

Desmosome

Question 6

Cardiac muscles are coupled via

Answer 6

Physically + electrically

Question 7

Cardiac muscle cells are coupled electrically via

Answer 7

Gap junctions

Question 8

Autorhythmic cells

Answer 8

Spontaneously fire action potentials

Question 9

Unique aspect of autorhythmic cells

Answer 9

They require no triggering event

Question 10

Instead of action potential, autorhythmic cells have

Answer 10

Pace (maker) setter potential

Question 11

Responsible for all triggering events of cardiac muscle

Answer 11

Autorhythmic cells

Question 12

What makes pace setter cell different from other cells?

Answer 12

Constant leak of sodium into cell

“Leak sodium channels”

Question 13

Why do pace maker cells not have a stable membrane potential?

Answer 13

Leak sodium channels

Question 14

What helps slow depolarization move to threshold?

Answer 14

T-type calcium channels

Question 15

Responsible for slow depolarization of cardiac cells

Answer 15

Leaky sodium channels

Question 16

At threshold, what channels open?

Answer 16

Long-type Calcium Channels

Question 17

Once L calcium channels open, what happens?

Answer 17

Calcium rushes into cell, fast depolarization

Question 18

At peak of self-induced action potential, what occurs?

Answer 18

Calcium channels close
Potassium channels open
Potassium moves out of cell

Question 19

Repolarization of autorhythmic cells occurs as a result of

Answer 19

Potassium channels open, Ca2+ channels close

Question 20

What happens during Repolarization of autorhythmic cells

Answer 20

K moves out of cell

Question 21

Cardiac action potential - rapid depolarization is due to

Answer 21

Opening of “fast” Na+ channels

Question 22

Difference between AP of normal cells vs cardiac cells

Answer 22

Plateau phase, no discernible repolarization phase

Question 23

Trigger of depolarization in cardiac cells

Answer 23

Autorhythmic cells

Question 24

After depolarization of cardiac cells, what happens?

Answer 24

Sodium channels close

Question 25

After depolarization + Na channels close, what occurs?

Answer 25

Plateau phase

Question 26

Plateau phase of cardiac cells

Answer 26

Calcium channels open - ca2+ move in | Potassium channels open - K moves out

Question 27

Main difference between normal AP and cardiac AP is a result of

Answer 27

Sustained depolarization - d/t Calcium

Question 28

Sustained depolarization allows for

Answer 28

Enough time for all cardiac cells (intercalated together) to depolarize as a single unit

Question 29

Important for both autorhythmic and cardiac cells

Answer 29

Calcium

Question 30

Locations of autorhythmic cells

Answer 30

1. SA node 2. AV node 3. Bundle of His (septum)

Question 31

Pathway of autorhythmic cells

Answer 31

SA —> AV —> Bundles of His

Question 32

Characteristic of Bundle of His

Answer 32

Deep fibers - Purkinje fibers — penetrate into walls of both ventricles (contraction at same time)

Question 33

Wave of APs - direction in heart

Answer 33

Begins at apex of heart and moves up ventricular wall

Question 34

SA Node is also known as

Answer 34

Pacemaker of heart

Question 35

What happens if SA node is too slow?

Answer 35

AV node will “fire first” | Ventricles do not benefit from atrial contraction

Question 36

Reason for difference in frequency between autorhythmic cells

Answer 36

Length of time cells spend in slow depolarization phase

Question 37

SA node speed

Answer 37

70-80 APs/minute

Question 38

AV node speed

Answer 38

40-60 APs/minute

Question 39

Bundle of His speed

Answer 39

20-40 APs/minute

Question 40

Time between SA —> AV node firing

Answer 40

AV nodal delay | 100 ms

Question 41

Reason for AV nodal delay

Answer 41

Time to allow maximal filling of ventricles

Question 42

Where does the SA node firing go?

Answer 42

1. Interarterial pathway (to LA) 2. Intermodal pathway (to AV node) 3. RA

Question 43

What defines systole/diastole

Answer 43

Ventricular contraction

Question 44

P wave

Answer 44

Depolarization of SA node + atria

Question 45

T wave

Answer 45

Repolarization of ventricles

Question 46

QRS complex

Answer 46

Depolarization of both ventricles

Question 47

Pause between P and QRS complex

Answer 47

AV Nodal Delay

Question 48

ECG without P wave

Answer 48

AV node fired before SA node | SA too slow or silent for a beat

Question 49

Pause between QRS and T wave

Answer 49

Blood is moving from ventricles into arteries

Question 50

ECG represents

Answer 50

Electrical events in heart

Question 51

R-R interval

Answer 51

Heart rate

Question 52

Passive filling occurs during

Answer 52

Ventricular + atrial diastole

Question 53

Ventricular filling is mostly

Answer 53

Passive

Question 54

Last bit of blood that goes into ventricles at end of diastole

Answer 54

Atrial kick

Question 55

Contraction of ventricles occurs

Answer 55

Following QRS

Question 56

Both AV valves shut when?

Answer 56

Ventricular pressure rises above atrial pressure

Question 57

First heart sound

Answer 57

AV valve closure

Question 58

All valves are shut

Answer 58

``` Isovolumetric contraction (Ventricles are contracting against constant volume) ```

Question 59

Aortic valve opening occurs

Answer 59

When ventricular pressure surpasses aortic pressure

Question 60

Ventricular ejection

Answer 60

Occurs after ventricular pressure > aortic pressure, arterial/pulmonic valve opens, rush of blood into aorta

Question 61

T wave

Answer 61

Repolarization/relaxation of ventricles | Decrease in V pressure

Question 62

Measure of cardiac performance

Answer 62

Ejection fraction

Question 63

Difference between SV and CO

Answer 63

``` SV= one beat CO = one minute ```

Question 64

Aortic/pulmonic valve closure

Answer 64

V pressure < aortic pressure

Question 65

Second heart sound

Answer 65

Aortic/pulmonic valve closure

Question 66

Isovolumetric relaxation

Answer 66

Atrial pressure < ventricular pressure < aortic pressure; all valves shut

Question 67

Dicrotic notch

Answer 67

Aortic valve shuts —> bump in aortic pressure

Question 68

Systolic blood pressure is an indirect measurement of

Answer 68

Ventricular pressure

Question 69

DBP is an indirect measure of

Answer 69

Conditions of arteries (elasticity) | Total Blood volume

Question 70

Cardiac suction

Answer 70

Dip in atrial pressure (atria are filling while ventricles are emptying)