Heart-2

backflow of blood

muscle is unresponsive to stimulation

• 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

control conduction of spontaneous action potentials that stimulate cardiac muscle fibers to contract

• 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

• cardiac cycle- contraction and relaxation of atria, rapidly followed by contraction and relaxtion of both ventricals
• systole- contraction
• diasole- relaxation

• 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

• atria fills
• semilunar valve closed
• AV valves loose
• ventricles fill

• SA node begins contraction
• spreads to AV node
• Atria force extra blood into ventricle
• semilunar valves close
• AV valves loose

• 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

• atria relaxed and continues to fill
• ventricle finish contraction
• AV valve close
• pressure on blood forces semilunar valve open
• ventricles eject blood

volume in ventricle at end of diastole (120-130 ml)

volume in ventricle at end of systole (60 ml)

volume ejected per beat from each ventricle (70 ml)

volume pumped out by each ventricle in 1 min . it is stroke volume X beats per minute

• preload (what you started with)
• contractility
• afterload(amt of pressure created by blood)

ion movement -depolarization /repolarization

• Pwave- SA node depolarize
• QRS- ventricles depolarize
• Twave- ventricle repolarize
• P-Q Time from AV node to purkinje fibers

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.

• diastolic + pulse pressure/3
• if low= organs not getting enough O2
• if high= heart is working too much