cardiac system continued

End diastolic volume

Amount of blood in ventricles (about 130ml)

Stroke volume

Amount of blood ejected during systole 70-80ml

End systolic volume

Amount of blood remaining 50 ml

Cardiac output

Amount of blood pumped by the left ventricle in 1 minute

factors affecting heart rate

Autonomic inner action and hormones

Sympathetic stimulation increases heart rate, parasympathetic stimulation decreases heart rate

Venous return

Amount of blood returning to heart via the veins

Bainbridge reflex

Atrial reflex responds to increased heart rate and sympathetic stimulation

P wave

Depolarization of atria, atria contracts after p wave

QRS Complex

Depolarization of ventricles, ventricles contract shortly after R wave peak

T wave

Depolarization of the ventricles

Cardiac contractile cells

Form walls of atria and ventricles branching striated cells with a single nucleus, propagate action potentials

Hormones affected heart rate contractility

Norepinephrine, epinephrine, and thyroid hormone

Affecting stroke volume

Filling time-duration of ventricular diastole

Preload-degree of ventricular stretching during ventricular diastole

affecting end diastolic volume

Frank starling principle: increased end diastolic volume makes an increase of stroke volume

Preload-contractility amount of force produced during contraction at a given preload

Sympathetic stimulation

Ventricles contract, ejection fraction increases, and end systolic volume

Parasympathetic stimulation

Decreases cardiac contraction, decreases the ejection fraction, increases end systolic volume

Affecting end systolic volume

After load-amount of tension produced by ventricles to open semilunar valves and eject blood

AL increases SV decreases

Venous return increases then end diastolic increases venous return decreases then:

End diastolic decreases as well

Filling time increases end diastolic volume increases filling time decreases then:

End diastolic volume increases as well

when end diastolic volume increases, then stroke volume increases, when end diastolic volume decreases:

Stroke volume decreases

Contractility increases end systolic volume decreases when contractility decreases:

End systolic volume increases

End systolic volume increases stroke volume decreases when end systolic decreases then:

stroke volume decreases

Vasoconstriction increases after load increases:

Then end systolic increases

Vasodilation decreases after load decreases:

Then end systolic volume decreases