Heart Flashcards
Positive inotropic factors
Calcium, glucagon, epinephrine, thyroxine, digitalis and sympathetic divisions of the ANS
Negative inotropic factors
anoxia, acidosis, potassium, some anesthetics, calcium channel blockers and the parasympathetic nervous system
3 factors that affect SV
- Preload
- Contractility
- Afterload
What is CO and its variables
Cardiac input–> Heart Rate and Stroke Volume
The average SV at rest
70ml/beat
Average heart rhythm `
75 beats/ min
Refractory period of the heart
250ms`
The heart begins at what voltage
-90mV
Define arrhythmia
any deviation from the normal sinus rhythm
Define Ectopic focus
when cells other than the SA node act as the pacemaker
Define fibrillation
when there is absolutely no regular rhythm
P wave represents
Atrial depolarization
QRS wave represents
Ventricle depolarization
T wave represents
ventricular depolarization
Lub sound is due to
AV valves closing
Dub sound is due to
SL valves closing
Define stenosis
valves not opening all the way