Rapid Interpretation of EKGs - Chapter 1 highlights

Question 1

Resting myocytes (aka polarized) have what electrical charge?

Answer 1

negative

Question 2

When myocytes contract, what is their electrical charge?

Answer 2

positive

Question 3

As the positive wave of depolarization within the myocytes flows toward a positive electrode, there is a _________ deflection recorded on EKG.

Answer 3

positive (or upward)

Question 4

The generation of pacemaking stimuli by the SA node is known as what?

Answer 4

automaticity

Question 5

What does the P wave represent?

Answer 5

atrial depolarization (contraction)

Question 6

The AV valves have two functions, what are they?

Answer 6

1. prevent backflow of blood to the atria

2. electrically insulate the ventricles from the atria

Question 7

When the conducting pathway gets to the AV valves, where does it go from there?

Answer 7

the AV node

it sits between the AV valves

Question 8

Which AV valve is between the right atrium and right ventricle?

Answer 8

tricuspid valve

(tRIcuspid is RIght side)

[got that one from the book, but i’m sure jake’s eye is twitching anyway]

Question 9

Which AV valve is between the left atrium and the left ventricle?

Answer 9

mitral valve

mitraL is Left side

Question 10

Cell to cell conduction of depolarization through the myocardium is carried by what kind of ions?

Answer 10

fast-moving sodium ions

Question 11

Slow conduction through the AV node is carried by what ions?

Answer 11

slow-moving calcium ions

Question 12

The AV node is connected to what?

Answer 12

the His bundle

Question 13

What comes after the His bundle?

Answer 13

the right and left bundle branches

Question 14

What are the His bundle and bundle branches “bundles” of?

Answer 14

purkinje fibers

Question 15

Purkinje fibers use what type of ions for the conduction of depolarization?

Answer 15

fast-moving sodium ions

Question 16

What do the purkinje fibers depolarize?

Answer 16

the ventricular myocytes

Question 17

Do the purkinje fibers penetrate into the myocardium?

Answer 17

no.

(the terminal filaments of the Purkinje fibers spread out just beneath the endocardium, and thus depolarization begins at the inside lining and proceeds toward the outside surface (epicardium) of the ventricles)

Question 18

What does the QRS complex represent?

Answer 18

depolarization of the ventricles

Question 19

What is the name of the horizontal segment of baseline that follows a QRS complex?

Answer 19

the ST segment

Question 20

From the beginning of the ST segment to the end of the T wave, what does this represent?

Answer 20

ventricular repolarization?

yes, ventricular repolarization

Question 21

In regards to ventricular repolarization, what phase is the ST segment and what phase is the T wave?

Answer 21

ST segment - plateau phase

T wave - rapid phase

Question 22

The QT interval (from the beginning of the QRS complex to the end of the T wave) represents what?

Answer 22

ventricular systole

Question 23

The whole representation of the P wave, QRS complex, the T wave, and the baseline that follows until another P wave appears is known as what?

Answer 23

a cardiac cycle

Question 24

Calcium ions cause what?

Answer 24

myocyte contraction

Question 25

The outflow of potassium ions causes what?

Answer 25

repolarization of myocytes

Question 26

Sodium ion movement produces what?

Answer 26

cell to cell conduction in the heart

except the AV node, which uses slow-moving calcium ions