Ekg Chap 2

Question 1

Two groups of cardiac cells

Answer 1

Myocardial cells
pacemaker cells

Question 2

Myocardial cells

Answer 2

“working cells”
Found in the thin muscular layer of the atrial wall, and thicker muscular layer of the ventricular wall

Question 3

What do myocardial cells contain

Answer 3

Myofibrils: contractible protein filament called actin and myosin

gives the indicator to contract and relax

Question 4

Pacemaker cells

Answer 4

found in the electrical conductivity of the heart

responsible for the spontaneous generation of electrical impulses

Question 5

Automaticity

Answer 5

Function - electrical

Pacemaker cells of the electrical conduction system

Question 6

Excitability

Answer 6

Function - electrical

responding to an electrical stimulus

All cardiac cells

Question 7

Conductivity

Answer 7

Function - electrical

conduct an electrical impulse to adjacent cardiac cell

All cardiac cells

Question 8

Contractility

Answer 8

Function - Mechanical

cardiac cells to contract in response of an electrical stimulus

Myocardial cells

Question 9

What happens during P-wave

Answer 9

SA node fires, causing atrial DEPOLARIZATION (atrium contracts)

Na+ enters, potassium gets out
negative to positive
resting to depolarized

Question 10

What happens during P-Q

Answer 10

Signal travels to AV node, which fires after blood leaves the atria completely

atria DEPOLARIZATION complete
Na+ is already inside
Positive

Question 11

What happens during QRS

Answer 11

Signal travels down Bundle of His and to the bundle branches
Purkinje fibers, causing ventricles to contract
Atra relaxing too

Ventricular depolarization begins
Na+ going out, potassium going in
Positive to negative

Question 12

Ventricular What happens to S-T

Answer 12

Ventricular depolarization complete

Positive to negative

Question 13

What happens to T wave

Answer 13

Ventricular repolarization begins

Question 14

Isoelectric line (flat line)

Answer 14

Ventricular repolarization is complete
Negative

Question 15

SA node

Answer 15

right upper atrium

60-100 beats/min

Pacemaker of heart

Question 16

Interatrial tract (bachmann/s bundle)

Answer 16

conducts impulse from SA node to left atrium

Question 17

Internodal tracts

Answer 17

three conduction tracts which conduct impulse from SA node through right atrium to AV node

Question 18

AV node

Answer 18

serves as backup pacemaker firing 40-60 beats/min

slows conduction of electrical impulse through AV node to allow time for atrial contraction, delay in AV node (flat line in PR)

Question 19

Bundle of His

Answer 19

Connects AV node to bundle branches

Question 20

Bundle branches

Answer 20

Right/left branch which conducts electrical impulses to the right/left ventricle

Question 21

Purkinje fibers

Answer 21

end of bundle branches, conducts electrical impulses to the ventricular myocardium

are capable of serving as backup pacemaker 30-40 beats/min or less

Question 22

P-wave represents which chamber of heart

Answer 22

Atria

Question 23

QRS wave represents which chambers of heart

Answer 23

ventricles

Question 24

ECG graph paper
Horizontal line measures

Answer 24

Time

each small square horizontally measures 0.04seconds

Question 25

ECG graph paper
Vertical line measures

Answer 25

Height/ amplitude/ voltage

1mm height

Question 26

How to count beats per minute on graph paper

Answer 26

Each “R” multiplied by 10, is a beat per minute