Physiology Midterm Review Flashcards

1
Q

EDV

A

End Diastolic Volume 110-120ml
Amount ventricle holds prior to contraction
Can be increased to 150-180ml

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2
Q

SV

A

Stroke volume 70ml

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3
Q

ESV

A

End Systolic Volume 40-50ml

Amount left over after ventricle contraction, can be as little 10-20ml

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4
Q

Ejection Fraction

A

SV/EDV ex. 70/110 = 64%

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5
Q

Depolarization/Contraction

A

P and QRS wave

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6
Q

Repolarization

A

T wave, atrial is hidden in QRS

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7
Q

P-R Interval

A

Time between firing SA node and contraction of ventricle -0.16 seconds

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8
Q

Q-T Interval

A

0.35s

Ventricle contraction/depolarization

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9
Q

T wave

A

Appears at end of potential

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10
Q

P Wave

A

Occurs at beginning of the contraction of the atria

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11
Q

Mean axis of the heart

A

59 degrees

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12
Q

Large QRS cause

A

Hypertrophy of ventricle

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13
Q

Depolarization

A

P and QRS waves

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14
Q

Repolarization

A

T wave, atrial hidden by QRS

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15
Q

AV receives signal from SA node _____s after origin

A

.03s

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16
Q

Signal is delayed in the AV node for

A

.09s

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17
Q

A final delay of ____s occurs in the penetrating bundles

A

.04s

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18
Q

Therefore, there is a ____s delay from the initial origin of signal

A

.16s

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19
Q

Sympathetic Innervation of the heart

A

Distributed to all parts of the heart, mainly the ventricle
Neurotransmitter = NE
Stimulates beta-1 adrenergic receptors
May increase permeability of fiber membranes to Sodium and Calcium

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20
Q

Parasympathetic Innervation of the heart

A

Vagus mainly to the SA and AV nodes.
Decreases rate of rhythm of SA node
Increases permeability of fiber membranes to K+ ions. Hyperpolarization

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21
Q

Hyperpolarization

A

-65 to -70 ml

vs -55 to -60

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22
Q

Bradycardia

A

Slow rate, <60 beats/minute
Causes: Athletic heart
Vagal Stimulation
Resp rate of sinus arrhythmia - resp centers are close to cardiac centers and can spill over

23
Q

Tachycardia

A

Fast rate, >100 beats/minute
Causes: Increased body temp (increases cell activity)
Stimulation of heart by sympathetic nerves
Toxic conditions of heart ie. infection

24
Q

Dropped QRS

A

2nd degree Atrioventricular block

2:1 rhythm or variations

25
Q

Circus Movements

A

Ventricular Fibrillation - no work is done, blood sits in ventricle and heart quivers

26
Q

3 Conditions leading to Circus Movements

A
  1. Pathway around circle is too long
  2. Path is constant, but velocity of conduction slows down
  3. The refractory period of the muscle might become greatly shortened. Can get another contraction when you shouldn’t because in relative refractory, not absolute refractory
27
Q

Capacitance

A

AKA Compliance = distensibility x volume

Vascular distensibility

28
Q

Resistance

A

Impediment to blood flow in a vessel

29
Q

Resistance value if vessels strongly consticted

A

4 PRU

30
Q

PRU

A

Peripheral Resistance Unit

31
Q

Resistance value if vessels dialated

A

Falls to as little as 0.2 PRU

32
Q

Cardiac Output

A

Rate of blood flow through the entire circulatory system

100 ml/sec

33
Q

Pressure difference from systemic arteries to systemic veins

A

100mmHg

34
Q

Resistance of entire systemic circulation =

A

100/100 or 1 PRU

35
Q

Flow

A

The greater the pressure difference, the higher the flow

The more the resistance, the slower the flow

36
Q

Blood volume

A
Systemic - 84%
-veins 64%
-arteries 13%
-systemic arterioles and capillaries 7%
Heart and Lungs - 16%
37
Q

Where is most of blood found?

A

Veins

64%

38
Q

T Wave

A

greatest portion of ventricular mass to repolarize first is the entire outer surface of ventricles, esp near apex

39
Q

Normal T waves in 3 bipolar leads

A

Is positive, as is most of QRS

40
Q

P Wave

A

Atrial depolarization begins in sinus node

ECG normally positive in all 3 leads

41
Q

Atrial T wave

A

Slower than in ventricles
Sinus node 1st part to become repolarized
Almost always masked by QRS

42
Q

Mean electrical axis

A

Summation of all vectors
Run neg to pos, inclined to L at 59 degrees, almost parallel to lead 2
Why lead 2 has highest peak

43
Q

Abnormal ventricular conditions that cause axis deviation

A

Change in position of heart
Hypertrophy of ventricle
Fluid in pericardium

44
Q

Increased Voltage

A

Sum of the voltages of all the QRS complexes of 3 leads is >4mV

45
Q

Decreased Voltage

A

Cardiac myopathies

Conditions surrounding ie. infection

46
Q

Currents of Injury

A

J point - reference point for analyzing current of injury

End of QRS

47
Q

Sinoatrial Block

A

Pacemaker not functioning/blocked
Sudden cessation of P waves
Resultant standstill of atria
Ventricle pick up new rhythm, usually originating in AV node (slower)
QRS is slowed, but not otherwise affected

48
Q

Atrioventricular Block

A
Conditions causing:
Ischemia of AV node d/t coronary insufficiency
Compression of AV bundle by scar tissue
Inflammation of AV node or bundle
Extreme stimulation of heart by vagus
49
Q

Incomplete Atrioventricular Block

A

1st degree - P-R interval > .20s
2nd degree - dropped QRS
-P is present
-dropped beats of ventricle 2:1 rhythm or variation

50
Q

Complete AV Block

A

No relation between rate of P waves and rate of QRS

-totally disconnected

51
Q

Paroxysmal Tachycardia

A

Heart becomes rapid in paroxysms - quick onset, rapid end

Pacemaker of heart suddenly shifts back to sinus node

52
Q

Defibrillator

A

Puts entire heart into state of absolute refractory and allows SA node to take over again and restart normal rhythm

53
Q

Laminar Flow

A

Blood flow has layers

  • flows at steady rate
  • flows in streamlines