Cardio Intro

Question 1

the fundamental electrical event of the heart

Answer 1

depolarization

Question 2

cardiac cells restoring their resting polarity

Answer 2

repolarization

Question 3

every wave on the ECG is the manifestation of _____ and _____

Answer 3

depolarization
repolarization

Question 4

what is the electrical power source of the wave of depolarization?

Answer 4

pacemaker cells

Question 5

the hard wiring of the heart that carries currents rapidly and efficiently to distant regions of the heart

Answer 5

electrical conducting cells

Question 6

the largest part of the heart tissue that is responsible for the heavy labor of relaxing, contracting and pumping blood

Answer 6

myocardial cells

Question 7

the pacemaker currents of which node bring cells to threshold more rapidly?

Answer 7

SA node

Question 8

what is the inherent rate of the SA node?

Answer 8

100 depolarizations per minute

Question 9

why do we want the SA node to reach threshold first?

Answer 9

we want it to drive the heartbeat forward

Question 10

cardiac muscle wants to fire in an ordered and rhythmic fashion. what is this called?

Answer 10

myogenic

Question 11

what is the condition in which cardiac muscle cells fire without a functioning SA node pacemaker and is chaotic and ineffective?

Answer 11

fibrillation

Question 12

why can the heart still beat properly even if its connections to the CNS are completely severed?

Answer 12

because the SA node has automaticity

Question 13

SA node is the first to _____ but the slowest to _____

Answer 13

depolarize
repolarize

Question 14

during sympathetic, what ions are increased?

Answer 14

K+ and Ca+

Question 15

what do norepi and epi during sympathetic affect?

Answer 15

atria and ventricles

Question 16

during parasympathetic, what ion leaks out of the SA node?

Answer 16

K+

Question 17

what does acetylcholie during parasympathetic affect?

Answer 17

atria

Question 18

what deflection does a positive charge moving towards a positive electrode give?

Answer 18

upward/positive deflection

Question 19

what deflection does a positive charge moving perpendicular to a positive electrode give?

Answer 19

no deflection

Question 20

what deflection does a positive charge moving away a positive electrode give?

Answer 20

downward/negative deflection

Question 21

electricity flows from _____ to _____

Answer 21

negative
positive

Question 22

lead V1 should be mostly _____

Answer 22

negative

Question 23

lead V6 should be mostly _____

Answer 23

positive

Question 24

what will be seen on the ECG if the heartbeat is initiated in the SA node and the atria contract?

Answer 24

P wave

Question 25

what is it called when the impulse slows as it passes through the AV node from the atria to the ventricles?

Answer 25

atrial kick

Question 26

why is the atrial kick important?

Answer 26

allows atria time to finish filling the ventricles

Question 27

what will be seen on the ECG during the rapid impulse through the His-Purkinje system?

Answer 27

PR interval

Question 28

what generates the QRS complex on the ECG?

Answer 28

depolarization of septum and ventricular walls

Question 29

what represents repolarization of the ventricles on the ECG?

Answer 29

ST segment and T wave

Question 30

what does the horizontal axis of the ECG measure?

Answer 30

time

Question 31

on the horizontal axis, how many seconds is one small box?

Answer 31

0.04 seconds

Question 32

on the vertical axis, how many millivolts is 1 large box?

Answer 32

0.5 mv

Question 33

what is the normal size of the P wave?

Answer 33

0.5 - 2.5 small boxes tall and wide

Question 34

how long in seconds is a normal PR interval?

Answer 34

0.12 - 0.20 seconds

Question 35

the first negative deflection following the PR segment is always known as what?

Answer 35

Q wave

Question 36

the first positive deflection following Q wave or PR segment is always known as what?

Answer 36

R wave

Question 37

the negative deflection that extends below baseline after the R wave is known as what?

Answer 37

S wave

Question 38

how long is a narrow QRS complex?

Answer 38

less than 3 small boxes

Question 39

what does a narrow QRS complex indicate?

Answer 39

signal came from above the AV node

Question 40

what does a wide QRS complex indicate?

Answer 40

previous AMI

Question 41

what does the ST segment represent?

Answer 41

refractory period

Question 42

what does the T wave represent?

Answer 42

repolarization of the ventricles

Question 43

what is the max amplitude of the T wave in the limb leads?

Answer 43

5mm (1 big box)

Question 44

what is the max amplitude of the T wave in the chest leads?

Answer 44

10mm (2 big boxes)

Question 45

what measure the time of ventricular depolarization and repolarization?

Answer 45

QT interval

Question 46

what is the normal duration of the QT interval?

Answer 46

9-11 small boxes

Question 47

what does the U wave represent?

Answer 47

repolarization of the purkinje fibers

Question 48

what is the max amplitude of the U wave?

Answer 48

1 mm (1 small box)