BISC306 Lecture Notes - Lecture 3: Dromotropic, Back Pressure, Atrioventricular Node
23 Oct 2017
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Document Summary
Electrocardiogram (ecg: electrodes placed on the surface of an organism or inserted into an organism can record voltage changes caused the electrical activity of the heart, specific electrical events are correlated with the ecg. Depolarization of the atria and ventricles are responsible for ecg signal. Abnormal ecg: atrial fibrillation caused by ectopic foci. Mechanical properties of the heart: stroke volume (sv) is the volume of blood ejected by the left or right ventricle during a heart beat. Sv= end of diastolic volume end systolic volume. Typical values for left ventricle at rest * Sv= 120ml-50ml=70ml: cardiac output (co) is usually expressed in l/min and is the output from either the left or right ventricle. Co= 71bpm x 0. 07 l/beat = 5 l/min. End diastolic volume (edv) is determined by: venous filling pressure, force of atrial contraction, distensibility of ventricle, timing of filling. End systolic volume (esv) is determined by: force of ventricular contraction, back pressure in outflow arteries.
