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
what does a cardiac cycle consist of? what is diastolic? systolic?
- contraction and relaxation of atria, rapidly followed by contraction and relaxtion of both ventricals
Phases of cardiac cycle?
1) Ventricular-Atrial diastole
*semilunar valves close
*AV valves open
* 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
*semilunar valves open
what happens when heart is in complete relaxation?
semilunar valve closed
AV valves loose
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
structures and function