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Five phases of cardiac cycle & Atrial contraction

By: HWC, Views: 7759

1. Atrial contraction (atrial systole). 2. Isovolumetric (ventricular) contraction. 3. Ventricular ejection. 4. Isovolumetric (ventricular) relaxation. 5. Passive ventricular filling. Beginning of cardiac cycle • Prior to atrial contraction: • Atria and ventricles are relaxed....

Isovolumetric VC, Ventricular ejection, Isovolumetric & Passive ventricular filling

By: HWC, Views: 7682

• Isovolumetric means that blood volume does not change. • Ventricular blood volume and cell length remain constant. • With valves closed and contraction continuing, ventricular pressure continues to rise. • Ventricular pressure rises above arterial pressure. • Increased ventr...

Stroke volume - afterload definition & hypertension

By: HWC, Views: 7184

• Pressure (or other resisting force) that ventricles must overcome to push open semilunar valves and eject blood. ▪ Normally, the left ventricle blood pressure must overcome arterial pressure in the aorta. ▪ Abnormally high blood pressure, or hypertension, increases aortic pressure w...

Electrical changes in the heart

By: HWC, Views: 7562

• ECG: Graph of the voltage changes that occur during the cardiac cycle. • Readings are taken by electrodes placed on the surface of the body. • Electrodes detect voltage changes caused by the electrical activity of the heart. • P wave = atrial excitation (atrial depolarization). ...

Automated external defibrillator (AED)

By: Administrator, Views: 10785

An automated external defibrillator (AED) is a portable electronic device that automatically diagnoses the life-threatening cardiac arrhythmias of ventricular fibrillation and pulseless ventricular tachycardia, and is able to treat them through defibrillation, the application of electricity which...

Stroke volume

By: HWC, Views: 7720

Preload definition • Preload is the degree of stretch of cardiac muscles cells prior to contraction. • The amount of stretch is related to the end-diastolic volume[EDV]. • Increased return blood flow from the veins increases end-diastolic volume. Cardiac muscle sarcomeres stretch and ...

Cardiac Cycle (Part 3 of 4)

By: Administrator, Views: 10305

Ventricular contraction

Definitions of stroke volume, preload definition & Factors influencing stroke volume

By: HWC, Views: 7508

• Stroke volume is directly correlated with cardiac output-the greater the stroke volume the greater the cardiac output. • Stroke volume represents the difference in the amount of blood between: • the volume in the ventricles at the end of diastole (end-diastolic volume EDV); • the ...

Exercise and cardiac output & Definition of stroke volume

By: HWC, Views: 7674

▪ Cardiac output: • Maintains blood flow throughout the body. • Measure of blood volume ejected from the heart over a given time. • Determined by multiplying heart rate by stroke volume (CO = SV x HR). • Heart rate: Number of beats/min. • Stroke volume: Amount of blood eject...