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backflow of blood
muscle is unresponsive to stimulation
what causes atrial depolarization? repolarization? Plateau?
- depolarization- voltage gated fast NA+ channels open
- plateau- voltage gated slow Ca+ channel open and close of some K+ channels
- repolarization- opening of voltage gated K+ channels and closing of CA+ channels
what is conducting system?
control conduction of spontaneous action potentials that stimulate cardiac muscle fibers to contract
flow of atrial depolarization?
- 1) SA node depolarizes sends wave through walls of
- 2) Atrium down to
- 3) AV node
- 4) Bundle of His
- 5) R and L bundle branches
- 6)Purkinje Fibers
what does a cardiac cycle consist of? what is diastolic? systolic?
- cardiac cycle- contraction and relaxation of atria, rapidly followed by contraction and relaxtion of both ventricals
- systole- contraction
- diasole- relaxation
Phases of cardiac cycle?
- 1) Ventricular-Atrial diastole
- *atria fills
- *semilunar valves close
- *AV valves open
- *ventricles fill
- 2)Atrial Systole
- *depolarize atria
- * semilunar valve closes
- * AV valve open
- *Atria forces extra blood into ventricles
- 3) Atrial diastole/Ventricle systole begins
- *atrial contraction finished and begin to fill
- *depolarization of ventricles
- *semilunar valve closes
- *AV valve closes
- 4)Ventricle systole finishes
- *ventricle ejection
- *semilunar valves open
what happens when heart is in complete relaxation?
- atria fills
- semilunar valve closed
- AV valves loose
- ventricles fill
what happens when atria begins contraction?
- SA node begins contraction
- spreads to AV node
- Atria force extra blood into ventricle
- semilunar valves close
- AV valves loose
what happens in ventricular contraction
- atrial contraction finished - relaxed
- atria begins to fill
- contraction to bundle of His and through ventricles
- semilunar valve close
- AV valve tighten and close
- pressure on blood increase d/t contraction
what happens at ventricular contraction?
- atria relaxed and continues to fill
- ventricle finish contraction
- AV valve close
- pressure on blood forces semilunar valve open
- ventricles eject blood
what is EDV (end diastolic volume)?
volume in ventricle at end of diastole (120-130 ml)
what is end systolic volume (ESV)?
volume in ventricle at end of systole (60 ml)
what is stroke volume? (sv)
volume ejected per beat from each ventricle (70 ml)
what is cardiac output?
volume pumped out by each ventricle in 1 min . it is stroke volume X beats per minute
what influences stroke volume?
- preload (what you started with)
- afterload(amt of pressure created by blood)
what does an EKG measure?
ion movement -depolarization /repolarization
What happens during Pwave? QRS? T wave? P-Q?
- Pwave- SA node depolarize
- QRS- ventricles depolarize
- Twave- ventricle repolarize
- P-Q Time from AV node to purkinje fibers
MI- myocardial infarction
death of heart muscle from lack of O2, and can not be regenerated. A blood clot is cause
heart pain from ischemia of cardiac muscle
difference between apical and radial pulse
- difference between systolic and diastolic
- amount of blood forced from hart during contraction , working condition of heart.
mean arterial pressure? what if its low? high?
- diastolic + pulse pressure/3
- if low= organs not getting enough O2
- if high= heart is working too much