Physiology Midterm Review Flashcards
EDV
End Diastolic Volume 110-120ml
Amount ventricle holds prior to contraction
Can be increased to 150-180ml
SV
Stroke volume 70ml
ESV
End Systolic Volume 40-50ml
Amount left over after ventricle contraction, can be as little 10-20ml
Ejection Fraction
SV/EDV ex. 70/110 = 64%
Depolarization/Contraction
P and QRS wave
Repolarization
T wave, atrial is hidden in QRS
P-R Interval
Time between firing SA node and contraction of ventricle -0.16 seconds
Q-T Interval
0.35s
Ventricle contraction/depolarization
T wave
Appears at end of potential
P Wave
Occurs at beginning of the contraction of the atria
Mean axis of the heart
59 degrees
Large QRS cause
Hypertrophy of ventricle
Depolarization
P and QRS waves
Repolarization
T wave, atrial hidden by QRS
AV receives signal from SA node _____s after origin
.03s
Signal is delayed in the AV node for
.09s
A final delay of ____s occurs in the penetrating bundles
.04s
Therefore, there is a ____s delay from the initial origin of signal
.16s
Sympathetic Innervation of the heart
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
Parasympathetic Innervation of the heart
Vagus mainly to the SA and AV nodes.
Decreases rate of rhythm of SA node
Increases permeability of fiber membranes to K+ ions. Hyperpolarization
Hyperpolarization
-65 to -70 ml
vs -55 to -60