Unit 2 Exam Lab 8

Question 1

The correct sequence of the wave of depolarization that passes through the heart is:

1 = atrioventricular (AV) node

2 = sinoatrial (SA) node

3 = Purkinje fibers

4 = bundle of His

5 = bundle branches

Answer 1

2,1,4,5,3

Question 2

A resting membrane potential of -85 mV means that

Answer 2

the inside of the cell is more negative with respect to the outside of the cell.

Question 3

During membrane depolarization, ______move _____ the cell through _____.

Answer 3

Na+, into, voltage gated channels

Question 4

During membrane repolarization, _____ move _____ the cell through _____.

Answer 4

K+, out of, voltage gated channels

Question 5

mass of cells that function as one

Answer 5

functional syncytium

Question 6

cells capable of spontaneously depolarizing

Answer 6

pacemaker cell

Question 7

pacemaker cell located in an unexpected site

Answer 7

ectopic pacemakers

Question 8

baseline for ECG

Answer 8

isoelectric line

Question 9

anatomical structure responsible for spread of wave of depolarization from cell to cell in cardiac tissue

Answer 9

intercalated dics

Question 10

anatomical structure that prevents the spreading of action potentials directly from atrial myocardium to the ventricular myocardium

Answer 10

exoskeleton, fibrotendonous rings

Question 11

which type of cardiac cells demonstrate slow response action potentials

Answer 11

SA node, AV node, ecotopic pacemaker cells

Question 12

which type of cardiac cells demonstrate fast response action potentials

Answer 12

bundle of his, bundle of branches, purkinje fibers, atrial muscle cells, ventricular muscle cells

Question 13

Which of the following can serve as pacemaker cells in the heart?

Answer 13

SA node, AV node, ecotopic pacemaker cells found in sites other than in the SA and AV nodes

Question 14

The intracellular concentrations of _____ are greater than the extracellular concentrations in both pacemaker and non-pacemaker cells.

Answer 14

K+

Question 15

The extracellular concentrations of _____ are greater than the intracellular concentrations in both pacemaker and non-pacemaker cells.

Answer 15

Na+ and Ca2+

Question 16

Which of the following statements best describe the movement of Na+ across the membrane during the prepotential stage of slow response action potentials.

Answer 16

Na+ diffuses slowly from the outside to the inside through leakage channels.

Question 17

Which of the following statements best describe the movement of K+ across the membrane during the prepotential stage of slow response action potentials?

Answer 17

K+ has reduced permeability for diffusing from the inside to the outside

Question 18

Which of the following statements best describe the movement of Ca++ across the membrane during the prepotential stage of slow response action potentials?

Answer 18

Ca++ diffuses slowly from the outside to the inside through leakage channels.

Question 19

During depolarization phase of slow response action potentials:, Na+:

Answer 19

is not involved in slow response action potential depolarization

Question 20

During depolarization phase of slow response action potentials:, K+:

Answer 20

is not involved in slow response action potential depolarization

Question 21

During depolarization phase of slow response action potentials:, Ca++:

Answer 21

diffuses rapidly from the outside to the inside of the cell

Question 22

During repolarization of slow response action potentials, Na+:

Answer 22

is not involved in slow response action potential repolarization

Question 23

During repolarization of slow response action potentials, K+:

Answer 23

diffuses rapidly from the inside to the outside of the cell

Question 24

During repolarization of slow response action potentials, Ca++:

Answer 24

is not involved in slow response action potential repolarization

Question 25

Which of the following best describes the role of Na+ movement through leakage channels at the resting membrane potential prior to a fast response action potential?

Answer 25

Na+ has limited permeability during resting membrane potential.

Question 26

Which of the following best describes the role of K+ movement through leakage channels at the resting membrane potential prior to a fast response action potential?

Answer 26

K+ diffuses from the inside to the outside through leakage channels.

Question 27

Which of the following best describes the role of Ca++ movement through leakage channels at the resting membrane potential prior to a fast response action potential?

Answer 27

Ca++ is not involved in development of the resting membrane potential.

Question 28

During depolarization of fast response action potentials, Na+:

Answer 28

diffuses rapidly from the outside to the inside of the cell

Question 29

During depolarization of fast response action potentials, K+:

Answer 29

is not involved in fast response action potential depolarization

Question 30

During depolarization of fast response action potentials, Ca++:

Answer 30

is not involved in fast response action potential depolarization

Question 31

During the plateau phase of fast response action potentials, Na+:

Answer 31

is not involved in fast response action potential plateau phase

Question 32

During the plateau phase of fast response action potentials, K+:

Answer 32

diffuses from the inside to the outside of the cell

Question 33

During the plateau phase of fast response action potentials, Ca++:

Answer 33

diffuses slowly from the outside to the inside of the cell

Question 34

During repolarization of fast response action potentials, Na+:

Answer 34

is not involved in fast response action potential repolarization

Question 35

During repolarization of fast response action potentials, K+:

Answer 35

diffuses rapidly from the inside to the outside of the cell

Question 36

During repolarization of fast response action potentials, Ca++:

Answer 36

is not involved in fast response action potential repolarization

Question 37

During the prepotential stage of slow response action potentials, the membrane potential becomes ____ negative on the inside with respect to the outside.

Answer 37

less

Question 38

Increasing the prepotential slope _____ the rate of spontaneous depolarizations of pacemaker cells, while decreasing the prepotential slope _____the rate of spontaneous depolarizations of pacemaker cells.

Answer 38

increases; decreases

Question 39

Distinguish between the steepness of the prepotential slope associated with pacemakers cells found in the the S-A node and the slope of the prepotential of pacemaker cells found in the the A-V node. Pacemaker cells in S-A node have a _______ slope than pacemaker cells in A-V node and therefore have a ______ rate of spontaneous depolarization.

Answer 39

steeper; faster

Question 40

An electrocardiogram is a record of: (2)

Answer 40

-electrical impulse conduction through the heart.

-extracellular recording of the sum of all the electrical activity of the heart over time

Question 41

P wave

Answer 41

atrial depolarization

Question 42

T wave

Answer 42

ventricular repolarization

Question 43

QRS complex

Answer 43

ventricular depolarization

Question 44

Lead 1

Answer 44

Left arm and right arm

Question 45

Lead 2

Answer 45

Right arm and left leg

Question 46

Lead 3

Answer 46

Left arm and left leg

Question 47

Einthoven’s Law

Answer 47

Lead II=Lead I+Lead III

Question 48

Increased P wave

Answer 48

Damaged atrial cells

Question 49

Increased PR interval

Answer 49

interference with conduction between SA node and purkinje fibers

Question 50

Increased QRS duration

Answer 50

non-sinultaneous activation of ventricles

Question 51

Decreasing the heart rate _____ QT interval.

Answer 51

increases

Question 52

Increasing the heart rate _____ cycle length.

Answer 52

decreases

Question 53

Which of the following conditions are or can be associated with a left mean electrical axis deviation?

Answer 53

-left ventricular hypertrophy
-systemic hypertension
-obesity
-pregnancy

Question 54

Which of the following conditions are associated with a right mean electrical axis deviation?

Answer 54

-right ventricular hypertrophy
-pulmonary hypertension

Question 55

impairment of conduction between the SA node and purkinje system

Answer 55

atrioventricular block

Question 56

impairment of conduction through the bundle branches, ventricles activated at different times

Answer 56

bundle branch block