Chapter 3

Question 0

Conductivity

Answer 0

Ability of myocardial cells to conduct electricity after stimulation

Question 1

Contractility

Answer 1

Heart tissue contracts in response to electrical stimuli

Question 2

Automaticity

Answer 2

Ability to initiate its own beats; will allow heart to beat when completely removed from body

Question 3

Rhythmicity

Answer 3

Capability of maintaining regularity of such pace making activity

Question 4

4 parts to the conduction system of the heart

Answer 4

SA node
AV node
Bundle of his
Purkinje fibers

Question 5

Components of EKG complex

Answer 5

P wave- atrial contraction

QRS complex- ventricular contraction

T and ST segment- ventricular relaxation

Question 6

P wave

Answer 6

First positive deflection in EKG complex

Question 7

Q wave

Answer 7

First negative deflection in QRS complex; large one represents myocardial death

Question 8

R wave

Answer 8

Second positive deflection

Question 9

S wave

Answer 9

Second negative deflection

Question 10

T wave

Answer 10

Third positive deflection; may be inverted in ischemia

Question 11

U wave

Answer 11

4th positive deflection immediately following T wave; not always visible

Question 12

J point

Answer 12

Junction between end of QRS and beginning of ST Segment

Question 13

Who invented practical EKG?

Answer 13

William Einthoven in 1924

Question 14

Einthoven’s law

Answer 14

Sum of the heights of QRS in leads I and III equals the height of QRS in lead II