Chapter 1: Basic Principles Flashcards

1
Q

Which scientist and in what year made a dead frog’s legs dance by electrical stimulation for the first time?

A

Luigi Galvani, 1790 (p. 1)

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2
Q

Which scientists and in what year discovered that the beating of the heart is due to a rhythmic discharge of electrical stimuli?

A

Kollicker and Mueller, 1855 (p. 2)

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3
Q

How did Kollicker and Mueller make this discovery?

A

They laid a motor nerve to a frog’s leg over its isolated beating heart, and saw that the leg kicked with each heartbeat. (p. 2)

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4
Q

Who invented the ECG as we know it?

A

Dr. Willem Einthoven

p. 4

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5
Q

What did Dr. Einthoven call his invention?

A
the ElectroKardioGram (EKG) which is the German spelling 
(p. 5)
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6
Q

The EKG records the…

A

…electrical activity of contraction of the myocardium.

p. 7

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7
Q

The interiors of ________ are ________ (“_________”) at rest, but when “depolarized” their interiors become ________ and the myocytes ________.

A
myocytes 
negative ("polarized") 
positive
contract
(p. 8)
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8
Q

Depolarization may be considered an advancing ____ of ________ charges within the heart’s myocytes.

A

wave
positive
(p. 9)

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9
Q

The cell-to-cell conduction of depolarization through the myocardium in initiated by fast moving ______ ions.

A

sodium

p. 9

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10
Q

The myocyte interiors regain their _______ ________ ______ during the ______________ phase.

A

resting negative charge
repolarization
(p. 10)

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11
Q

In reality, repolarization begins ___________ _____ depolarization, but the “initial” repolarization does not ______ __ ___.

A

immediately after
record on EKG
(p. 10)

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12
Q

Sensors called __________ are placed on the skin to detect the heart’s electrical activity.

A

electrodes

p. 11

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13
Q

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

A

positive
positive (upward)
(p. 12)

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14
Q

The generation of pacemaking stimuli is known as…

A

…automaticity.

p. 13

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15
Q

Other focal areas of the heart that have automaticity are called “____________ ____”.

A

“automaticity foci”

p. 13

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16
Q

Atrial depolarization (and ___________) is a spreading ____ of ________ charges within the atrial myocardial cells.

A

contraction
wave
positive

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17
Q

Each depolarization wave emitted by the SA node spreads through ____ _____, producing a _ ____ on EKG.

A

both atria
P wave
(p. 14)

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18
Q

In reality, the contraction of the atria _____ ______ than the duration of the _ ____.

A

lasts longer
P wave.
(p. 15)

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19
Q

The atrioventricular valves do two major things:

A
  • prevent backflow to the atria
  • electrically insulate the ventricles from the atria
    (p. 16)
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20
Q

The __ ____ is the ____ conducting path between the atria and the ventricles.

A

AV node
only
(p. 16)

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21
Q

Why does the wave of depolarization slow down when it enters the AV node?

A

To allow time for the blood in the atria to enter the ventricles.
(p. 19)

22
Q

What portion of the EKG represents the pause as depolarization slows at the AV node?

A

The isoelectric line following the P wave.

p. 19

23
Q

What ions are responsible for slowing conduction at the AV node?

A

calcium ions

p. 19

24
Q

After conducting slowly through the AV node, depolarization _______ ______ through the ______ of ___ and the ____ and _____ ______ ________.

A

rapidly shoots
Bundle of His
left and right Bundle branches
(p. 20)

25
The ventricular conduction originates at the ______ __ ___, which penetrates the AV valves, then immediately __________ (in the ________________ ______) into the left and right bundle branches.
Bundle of His bifurcates interventricular septum (p. 20)
26
The bundle of His, and bundle branches are "bundles" of...
...rapidly conducting Purkinje fibers. | p. 20
27
Purkinje fibers use ____-______ ______ ions for the conduction of depolarization.
fast-moving sodium | p. 20
28
The terminal filaments of the Purkinje fibers rapidly distribute depolarization to the...
...ventricular myocytes. | p. 21
29
The rapid passage of depolarization down the ventricular conducting system is too ____ to record on EKG; however, depolarization of the ventricular myocardium records as a ___ ______.
weak QRS complex (p. 21)
30
The terminal filaments of the Purkinje fibers spread out just beneath the ___________ that _____ both ventricular cavities, therefore ventricular depolarization begins at the ______ and proceeds toward the outside surface (__________).
endocardium, lines lining, epicardium (p. 21)
31
The Purkinje fibers ______ and _________ just beneath the endocardial lining, but they barely _________ into the myocardium.
branch, subdivide, penetrate | p. 21
32
The entire ventricular conduction system, i. e. the... ... is composed of...
...bundle of His through the terminal filaments... | ...Purkinje fibers that use fast-moving Na+ ions for conduction. p. 22
33
The Q wave, which is not always _______, is the first ________ deflection of the complex.
present downward (p. 23)
34
By convention, if there is any UPWARD deflection in a QRS complex that appears before a Q wave...
...it is not a Q wave, because the Q wave is always the first wave in the complex. (p. 23)
35
The upward _ ____ is followed by a downward _ ____.
R wave S wave (p. 24)
36
An upward wave is ALWAYS called...
...an R wave. | p. 24
37
What do we call a complex with a downward wave and no upward waves?
A QS wave; when there is no upward wave, we cannot determine whether it is a Q wave or an S wave, so it is called a QS wave. BUT, it is considered to be a Q wave when we look for Q's. (p. 25)
38
The T wave represents the...
...rapid phase of ventricular repolarization. | p. 27
39
Repolarization is accomplished by...
...potassium (K+) ions leaving the myocytes. | p. 27
40
Why is the QT interval a good indicator of repolarization?
Because repolarization comprises most of the QT interval. | p. 28
41
As a simple rule of thumb, the QT interval is considered normal when it is...
...less than half of the R-to-R interval at normal rates. | p. 28
42
Following depolarization, repolarization is due to the controlled _______ of __ ions from the myocytes.
outflow K+ (p. 30)
43
Cell-to-cell conduction (of depolarization) through the __________ is carried by ___ ____, however, __ ____ conduction is due to the ____ movement of ___ ions.
myocardium, Na+ ions, AV node, slow, Ca++ (p. 30)
44
Lead I is created by placing a positive electrode on... | ...and the negative electrode on the...
...the left arm ...right arm. (YouTube https://www.youtube.com/watch?v=URBREKIUALk)
45
Lead II is created by placing a positive electrode on... | ...and the negative electrode on the...
...the left foot | ...right arm.
46
Lead III is created by placing a positive electrode on... | ...and the negative electrode on the...
...the left foot. | ...left arm.
47
Phase 0 of the cardiac cycle of contraction begins with rapid depolarization due to...
...opening of voltage-gated fast sodium channels. | Powerpoint by Dr. Miller; "Basic EKG, Fall 2016"
48
Phase 1 is reached when the membrane potential is at its most ________ state.
positive | Powerpoint by Dr. Miller; "Basic EKG, Fall 2016"
49
The phase 2 plateau is due to opening of...
...voltage-gated slow calcium channels and closing of some of the potassium channels. (Powerpoint by Dr. Miller; "Basic EKG, Fall 2016")
50
Phase 3 is repolarization, which is due to...
...opening of voltage-gated K channels and closing of calcium channels. (Powerpoint by Dr. Miller; "Basic EKG, Fall 2016")
51
``` Events in the Cardiac Cycle: Phase 1: Phase 2: Phase 3: Phase 4: Phase 5: Phase 6: Phase 7: ```
1 - atrial systole, then mitral/tricuspid valves close producing S1 2 - isovolumetric contraction, then aortic/pulmonic valves open 3 - rapid ejection 4 - reduced ejection, then aortic/pulmonic valves close 5 - isovolumetric relaxation, then mitral/tricuspid valves open 6 - rapid filling 7 - reduced filling