Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology Exam 2: Lectures 8-16 > Lecture 8 > Flashcards

Lecture 8 Flashcards

1
Q

What is the SA composed of?

A

special cardiac muscle fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What do SA fibers connect directly to?

A

atrial fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The AV node receives signal from SA node ____ seconds after origin

A

.03

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Signal is delayed in AV node for _____ sec

A

.09

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

A final delay of _____ sec occurs in the penetrating bundles

A

.04

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

There is a _____ sec delay from the initial origin of the signal onset of ventricular contraction

A

.16

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the resting membrane potential of SA node fiber

A

-55 to -60 mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Fast sodium channels are already ______ at resting membrane potential of SA node. Slow sodium-calcium channels can _____

A

inactivated (blocked); open

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is ventricular fiber resting potential?

A

-85 to -90 mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is generated by action potentials in the SA node?

A

sinus rhythm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Action potentials that originate anywhere else are said to from an ______

A

ectopic focus or pacemaker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Where is the vagus nervous distributed?

A

SA and AV nodes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the neurotransmitter of vagus nerve?

A

acetylcholine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does acetylcholine do to heart rate?

A

decreases rate of rhythm of SA node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Acetylcholine ________ excitability of the AV junctional fibers, _______ transmission of the cardiac impulse into the ventricles

A

decreases; slowing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What increase permeability of fiber membranes to potassium ions?

A

acetylcholine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where is sympathetic innervation distributed to?

A

all parts fo the heart, mainly the ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the neurotransmitter of sympathetic innervation?

A

norepinephrine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does norepinephrine do?

A

stimulates beta 1 adrenergic receptors
increases depolarization rate
may increase permeability of fiber membranes to sodium and calcium ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the P wave?

A

atrial depolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the QRS wave?

A

ventricular depolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the T wave?

A

ventricular repolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

When does the P wave occur?

A

beginning of the contraction of the atria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

When does the QRS complex occur?

A

at the beginning of the contraction of the ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

When does repolarization of the ventricles?

A

end of the T wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How long is the P-Q (P-R) interval?

A

0.16 sec

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How long is the Q-T interval?

A

0.35 sec

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

The negative terminal of the recording limb lead I is connected to where?

A

right arm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

The positive terminal of the recording limb lead I is connected to where?

A

let arm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

The recording limb lead I looks at what?

A

heart from left to right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

The negative terminal of ECG of the recording limb lead II is connected to where?

A

right arm

32
Q

The positive terminal of ECG of the recording limb lead II is connected to where?

A

left leg

33
Q

Recording limb lead II looks at what?

A

heart from upper right to lower left

34
Q

The negative terminal of recording limb III is connected to where?

A

left arm

35
Q

The positive terminal of recording limb III is connected to where?

A

left leg

36
Q

The recording limb III looks at what?

A

heart from upper left to lower leg

37
Q

What is Einthoven’s triangle?

A

two arms and left leg form apices of triangle

38
Q

Normally in the ventricles, current flows from _______ to _____ primarily in the direction from the base of the heart toward the apex for most of the heart cycle until the very end

A

negative to positive

39
Q

The electrode nearer the base is ______ and the electrode nearer the apex is _____

A

negative; positive

40
Q

In the recording limb lead I where the right arm connects to the Ches is negative with respect to the point where the left arm connects, the ECG records ______

A

positive

41
Q

In recording limb lead II when the right arm is negative with respect to the left leg, the ECG records

A

positive

42
Q

In recording limb lead III when the left arm is negative with respect to the left leg, the ECG records

A

positive

43
Q

What is a vector?

A

an arrow that points in the direction of the electrical potential generated by the current flow, with the arrowhead in the positive direction

44
Q

Length of the arrow of a vector is drawn ______ to the voltage of the potential

A

proportional

45
Q

Axis for Lead I

A

two electrodes on two arms
R= negative
L= positive

46
Q

What is the direction of the axis for lead I?

A

0 degrees

47
Q

What is the axis for lead II?

A

electrodes on right arm and left leg
A: negative
L: positive

48
Q

What is the direction fo the axis for lead II?

A

60 degrees

49
Q

What is the axis for lead III?

A

electrodes on left arm and left leg
A: negative
L: positive

50
Q

What is the direction of the lead for lead III?

A

120 degrees

51
Q

When the vector in the heart is in a direction almost ______ to the axis of the lead, the voltage recorded in the ECG of this lead is very _____

A

perpendicular; low

52
Q

When the heart vector has almost the ____ axis as the axis of the lead, the entire voltage of the vector will be _____

A

same; recorded

53
Q

The ______ vector of the generated potential at a particular instant is called the _________ mean vector

A

summated; instantaneous

54
Q

The reference vector is ______ and extends toward a person’s ______ side; this reference direction= _____ degrees

A

horizontal; left; 0

55
Q

The QRS vector is about _____ degrees in relation to the zero reference point

A

+59

56
Q

What is the greatest portion of ventricular mass to repolarize first?

A

entire outer surface of the ventricles, especially near the apex

57
Q

What areas of the T wave normally repolarize last?

A

endocardial areas

58
Q

Ventricular vector during repolarization is _____ the apex of the heart

A

toward

59
Q

Normal T-wave in all three bipolar leads is ____

A

positive

60
Q

Where does atrial depolarization begin?

A

sinus node

61
Q

Where is vector direction in the p-wave?

A

in the direction of the axes of the three standard bipolar limb leads

62
Q

True or false: the ECG is normally negative in all three leads in the p-wave

A

false, they are usually positive

63
Q

Spread of depolarization through atrial muscles is _____ than in the ventricles

A

slower

64
Q

In the atrial t-wave the ________ area is the first part to become depolarized

A

sinus node

65
Q

In the atrial t-wave at the beginning of repolarization the sinus node is _____ with respect to the rest of the atria

A

postive

66
Q

Atrial t-wave is almost always obscured by what?

A

QRS wave

67
Q

What are abnormal ventricular conditions that cause axis deviation?

A 
change in position of heart in the chest 
hypertrophy of one ventricle 
bundle branch block
fluid in pericardium 
pulmonary emphysema
68
Q

What is the most common cause increased voltage in the standard bipolar leads?

A

hypertrophy of the ventricle

69
Q

What decreases voltage in abnormal voltages of the QRS complex?

A

caused by cardiac myopathies

caused by conditions surrounding the heart

70
Q

How long does the normal QRS lasts?

A

0.06 to 0.08 seconds

71
Q

in hypertrophy or dilation of the left or right ventricle, QRS may be prolonged to _______

A

0.09 to 0.12 seconds

72
Q

What are the abnormalities causing current of injury?

A

mechanical trauma
infectious processes
ischemia

73
Q

What are the effect of current of injury on the QRS complex?

A

abnormal negative current flows from infarcted area and spreads toward the rest of the ventricles

74
Q

What is the J point?

A

reference point for analyzing current of injury

75
Q

Where does the J point occur?

A

at the end of the QRS wave and is the point at which all parts of the ventricle become depolarized (including the injured areas)

Physiology Exam 2: Lectures 8-16 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions