Week 1

Question 1

Polarization / Depolarization

Answer 1

The inside of a cardiac cell being kept negatively charged / cardiac cells losing their internal negative charge

Question 2

Pacemaker Cells

Answer 2

Small cells that depolarize spontaneously over and over again at a particular rate; serve as the source of a wave of depolarization that initiates one complete cycle of cardiac contraction and relaxation

Question 3

SA Node

Answer 3

Cluster of pacemaker cells that are located up in the right atrium

Question 4

What type of cells constitute the majority of heart tissue?

Answer 4

Myocardial cells; responsible for heavy labor of repeatedly contracting and relaxing & delivering blood to body

Question 5

3 Characteristics of an EKG wave:

Answer 5

Duration (mili seconds), Amplitude (mV), Configuration (shape)

Question 6

Horizontal axis / what does 1 small square measure / 1 large square?

Answer 6

Time / .04 seconds / .2 seconds

Question 7

Vertical Axis / Small Square / Large Square

Answer 7

Voltage / .1 mV / .5 mV

Question 8

Delay after the P-wave is caused by / why is it necessary?

Answer 8

Electric activity is held up at AV node / necessary to allow right atrium to finish contracting before the ventricles contract

Question 9

Pathway of electricity through the heart

Answer 9

SA node in R atrium –> AV node –> Bundle of HIS –> R and L bundle branches –> Terminal Purkinje Fibers

Question 10

Q-Wave:

Answer 10

First downward deflection = depolarization of the septum

Question 11

R-wave:

Answer 11

First upward deflection; 2nd upward deflection = R prime

Question 12

S-wave:

Answer 12

1st downward deflection after an upward deflection

Question 13

Describe Leads 1-3:

Answer 13

1: L arm pos, R arm neg, 0 degree angle. 2: Legs pos, R arm neg, 60 degrees. 3: L arm neg, legs pos, 120 degrees.

Question 14

Describe the Augmented Leads:

Answer 14

AVL: L arm pos, all other limbs neg, -30. AVR: R arm pos, all other limbs neg, -150. AVF: legs neg, all other limbs pos, 90.

Question 15

Best leads for viewing the inferior surface of the heart?

Answer 15

2, 3, AVF

Question 16

Where are the 6 precordial leads placed?

Answer 16

(1) 4th IC space R of sternum, (2) 4th IC space L of sternum, (3), btw 2 & 4, (4) 5th IC space MC line, (5) btw 4 & 6, (6) 5th IC space MA line

Question 17

Length of PR Interval:

Answer 17

.12 sec - .2 seconds (3-5mm)

Question 18

Length of QRS Complex:

Answer 18

.06-.1 seconds

Question 19

Contractility:

Answer 19

Ability of cardiac muscle to convert electrical signal into mechanical action

Question 20

Automaticity:

Answer 20

Ability of cardiac cell to depolarize spontaneously

Question 21

Excitability:

Answer 21

Ability of cardiac muscle to respond to stimuli and generate Action Potential

Question 22

Fast Response Action Potentials - found in what cells / caused by influx of ______________?

Answer 22

Cardiac cells that are NOT pacemaker cells (myocytes, Purkinje fibers, bundle branches, etc) / Caused by influx of Sodium

Question 23

Slow Response Action Potentials - found in what cells / caused by influx of __________?

Answer 23

Cardiac cells that are pacemaker cells (cells in SA and AV node) / Caused by influx of Calcium