Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Physiology > Cardiac Mechanics and EKG > Flashcards

Cardiac Mechanics and EKG Flashcards

(75 cards)

Start Studying
1
Q

pacemaker cells

A

initiate depolarization, autorhythmic

SA node, AV node, purkinje fibers

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

contractile cells

A

forceful contraction

myocardium

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

what helps the heart to function as one unit?

A

gap junctions by sending charge on to the next quickly

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

phase 0 action potential cardiac

A

depolarization

voltage gated Na channels

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

phase 1 action potential cardiac

A

initial repolarization

closing VGNa

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

phase 2 action potential cardiac

A

plateau

opening VGCa

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

phase 3 action potential cardiac

A

repolarization

opening VGK

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

phase 4 action potential cardiac

A

resting membrane potential

K+ leak channels

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

what changes during action potential in cardiac muscle cells?

A

permeability

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

absolute refractory period

A

0.2-0.25 s

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

relative refractory period

A

0.05 s

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

do skeletal muscles or cardiac muscles have longer refractory periods?

A

cardiac muscles

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

what is the mechanism of cardioplegic solution?

A

increases extracellular K+

depolarizes and then cannot repolarize

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

two ways to alter contraction

A

augmenting force

decreasing force

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

two ways to augment force of contraction

A 
increase calcium (beta agonist)
sensitizing contractile machinery
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how does the beta agonist increase calcium?

A

activates PKA that phosphorylates VGCC and makes them more likely to be open

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

way to decrease force of contraction

A

decrease calcium

beta blocker

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

what is special about pacemaker cells

A

contain fewer contractile fibers
no organized sarcomeres
faster conducting rate

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

If- funny current other name

A

hyperpolarization activated cyclic nucleotide gated

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

funny current mechanism

A

resting potential is unhill curve and is caused by leaky sodium current

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

which action potential phase is absent in SA and AV nodes compared to cardiac muscle cells

A

phase 2

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

intrinsic depolarization rate SA node

A

60-80bpm

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

intrinsic depolarization rate AV node

A

40-55bpm

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

intrinisic depolarization rate purkinje fibers

A

15-35bpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what type of cells have funny current?
pacemaker
26
chronotropic
increase heartrate
27
lusitropic
increase rate of relaxation
28
phospholambin
inhibits SERCA
29
beta 1 agonist
increases HR by increasing cAMP
30
what nerve is the parasympathetic mediated through?
vagus nerve
31
2 ways that parasym works to decrease HR
increases K+ current (hyperpolarize) | inhibits AC and decreases cAMP and PKA
32
conduction velocity SA node
1m/s
33
conduction velocity AV node
0.05 m/s
34
total time from SA node to bundle branch
0.16
35
conduction velocity purkinje fibers
1.5-4.0m/s
36
conduction velocity muscle cells
0.3-0.5 m/s
37
4 common inotropic agents used for short term HF
digitalis(digoxin) dobutamine milrinone levosimendan
38
What is digoxin mechanism of action
``` inhibits NaK pump increases Ca slows conduction of AV node depresses SA node does NOT increase HR ```
39
dobutamine mechanism of action
beta 1 agonist increases Ca increases HR
40
milrinone mechanism of action
phophodiesterase 3 inhibitor increases cAMP increases Ca increases HR
41
levosimendan mechanism of action
increases Ca sensitization of troponin C does not increase HR does NOT cause arrhythmias
42
1 large box ECG = __ mV?
0.5mV
43
1 large box ECG= __ sec?
0.2 sec
44
how many large boxes = 1sec?
5 large boxes
45
normal P-R interval length
<0.2 sec (< 1 large box)
46
normal QRS complex width?
<3 small boxes
47
what does the height of the QRS complex indicate?
muscle mass
48
What can cause a wide QRS?
bundle branch block
49
normal QT interval
0.35-0.42s
50
QTc
corrected QT interval
51
hypocalcemia effect on QT interval
long
52
hyercalcemia effect on QT interval
short
53
what is the ion channel involved in prolonged QT interval due to genetics?
K+
54
What usually causes ST segment changes?
MI | STEMI
55
what do ECGs measure
the potential difference between two leads (outside the cardiomyocytes) this is why it is positive
56
what does an ECG read when the heart is at rest?
0
57
what does the lead two measure
QRS complex
58
why is the QRS complex positive?
the negative lead has more neg charges around it and positive lead has more pos charges around it
59
during repolarization of the ventricles what repolarizes first?
last area to depolarize is the first to repolarize | epi to endo
60
t wave
repolarization of the ventricle
61
why would the t wave be inverted
if the first area to depolarize is the first area to repolarize
62
what are the causes of inverted t wave
coronary ischemia hypertrophy bundle branch block
63
bradycardia speed/ causes
<60bpm | vagal nerve stimulation, athlete, cold temp
64
SA block
missed beat
65
AV block causes
vagal stimulation ischemia calcification inflammation
66
wenckebach
AV block 2nd degree type 1 (longer and longer)
67
tachycardia
>100bpm
68
tachycardia causes
``` sympathetic nerve stimulation epi drugs increased temp hyperthyroidism blood loss fever ```
69
supraventricular tachycardia rate
100-250 bpm
70
How to help reduce SVT?
adenosine | vagal maneuvers
71
torsade de pointes
looks like a ribbon twisting of the QRS prolonged QT syndrome moves to Vfib
72
causes of premature contractions
ischemia calcification chemicals genetic
73
causes of premature ventricular contractions
MI/ ischemia | drugs that cause excitability
74
treatment for afib
antiarrhythmics anticoagulants ablation electrical cardioversion
75
mean QRS axis deviation
right or left BBB | hypertrophy

Physiology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions