Electrical Activity of Heart School Questions

Question 1

Able to generate impulses

Membrane Potential is UNSTABLE

Answer 1

SA node

Question 2

Period when ventricles are completely unexcitable

Answer 2

ARP

Question 3

ARP Corresponds approximately to period of

Answer 3

Ventricular Repolarization

Ventricular Contraction

Question 4

During ? period a new AP CANNOT be elicited

Answer 4

ARP

Question 5

During ? period a new AP can be elicitied

Answer 5

Relative Refractory Period

Question 6

“Tetany”, a period of constant contraction does not occur in Myocardium because ? is of each cell is LONG or SHORT

Answer 6

Refractory Period

Long

Question 7

Natural Rate of Rhythmic Discharge is greated in?

Answer 7

SA node

Question 8

Coronary Blood Flow is ? by activation of SNS

Answer 8

increased

Question 9

Rate of Conduction of Purkinje Fibers is ? by activation of SNS

Answer 9

increased

Question 10

What happens to slope of the Frank-sturling curve with INCREASED activation of the Frank Sterling Curve

Answer 10

Increased

Question 11

Activation of SNS or PNS will INCREASE slope of Frank Sterling curve?

Answer 11

Increased

Question 12

HR will ? with slowing of AP through AV node

Answer 12

Decrease HR

Question 13

Dry mouth is sign of ? stimulation

Answer 13

SNS

Question 14

Hypertension is sign of ? stimulation

Answer 14

SNS

Question 15

Profuse Sweating is sign of ? stimulation

Answer 15

SNS

Question 16

Slowing of the HR is sign of ? stimulation

Answer 16

Parasympathatic NS

Question 17

Where is the Conduction Velocity slowed down?

Answer 17

AV node

Question 18

The conduction Velocity of AV node

Answer 18

0.12 s

Question 19

The conduction velocity in the in Purkinje Fibers is ______ , than in the AV node

Answer 19

Faster

Question 20

Summation of Contractions (produce more contractions) can occur in Skeletal or Cardiac Muscle?

Answer 20

Skeletal

Question 21

Summation of Contraction cannot occur in

Answer 21

Cardiac Myocytes

Question 22

Absolute Refractory Period is longer in

Answer 22

Cardiac Myocytes

Question 23

PHASE 0 AP change mediated by

Answer 23

Increased Membrane Permeability to Na

Question 24

Phase 2 AP change mediated by

Answer 24

Voltage Gated Ca2+ ion channels

Question 25

Depolarization phase of AP mediated by

Answer 25

Voltage Gated Na+ ion channels open

Question 26

Prolonged period of Slow Repolarization

Answer 26

Plateau Phase

Question 27

Prolonged Depolarization is due to ? remaining open

Answer 27

Ca2+ channels

Question 28

Unlike other Cardiac Muscle, the entry of ? into PACEMAKER CELLS, is responsible for depolarization phase of AP

Answer 28

CA2+

Question 29

Increased Extracellular Ca 2+ causes : ____ contractility ____ HR

Answer 29

Increased Contraction | Increased HR

Question 30

Proper Sequence of Cardiac Excitation Ending

Answer 30

Bundle of His --> Purkinje Fibers

Question 31

the only point of contact between the Atria and Ventricles is

Answer 31

AV node

Question 32

Chambers in which Purkinje Fibers Distribution the AP

Answer 32

Both Ventricles

Question 33

Factors which decreased the contractility of the heart are known as

Answer 33

Negative Inotropic

Question 34

If membrane potential moves towards 0, because of Ionic concentrations ? one wide contractility will

Answer 34

Decrease?

Question 35

Spontaneous depolarization is caused be | Efflux of

Answer 35

Efflux of K+

Question 36

Membrane potentials in proper sequence

Answer 36

``` Threshold Voltage Na+ Open K+ open Na Close Membrane Depolarization K+ close ```

Question 37

Low resistance pathways between myocardial cells that allow for the spread of action potentials are

Answer 37

Gap junctions

Question 38

Main Difference between Excitation-Contraction Coupling in Skeletal and Cardiac Muscle is

Answer 38

Entry of small amt of Ca2+ from ECF is essential for CARDIAC CONTRACTION

Question 39

Entry of small art of Ca2+ from ECF is essential for

Answer 39

Cardiac Contraction

Question 40

Spread of cardiac excitation between contracting cells is ensured by

Answer 40

Gap Junctions | Desmosomes

Question 41

The ECG is a recording of a single cell point in time single AP true or false

Answer 41

FALSE

Question 42

During which phase of ECG shown are both atria depolarized

Answer 42

a (first segment)

Question 43

During which phase of ECG show Depolarization of Ventricles

Answer 43

B-C-D (Second segment, QRS)

Question 44

ECG - depolarization of Ventricles

Answer 44

``` "e' T wave (last segment, opposite of A) ```

Question 45

Complete depolarization of atria and ventricles

Answer 45

T

Question 46

known name of wave | Depolarization of AV NODE

Answer 46

A

Question 47

ECG | AV node delay can be mostly seen in

Answer 47

P-Q Segment

Question 48

which wave is due to depolarization of ventricles? | true quesiton

Answer 48

T wave

Question 49

which wave is not visible on EKG form?

Answer 49

AV node depolarization

Question 50

wave | depolarization of R+L atria

Answer 50

P wave

Question 51

? ekg for tiem to traverse atria------->purkinje cells

Answer 51

P-R interval

Question 52

QRS complex represents

Answer 52

Depolarization of R+L ventricles

Question 53

repolarization of atria

Answer 53

QRS complex

Question 54

rEpolarization of ventricles

Answer 54

T wave

Question 55

absent p wave

Answer 55

Lack of SA node conductivity

Question 56

qrs complex is spread of excitation from ___complex thru the ____

Answer 56

AV node | Ventricles

Question 57

Reduced Ventricular Ejection fraction wave

Answer 57

T WAVE

Question 58

EKG, stimulation of the Sympathetic nervous system

Answer 58

shortens Q-T interval