Search results for: 'heart defects'

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By: Administrator, Views: 10891

Diastole and systole are two phases of the cardiac cycle. They occur as the heart beats, pumping blood through a system of blood vessels that carry blood to every part of the body. Systole occurs when the heart contracts to pump blood out, and diastole occurs when the heart relaxes after contract...

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Introduction to Dysrhythmia

By: Administrator, Views: 10663

Cardiac dysrhythmias are a problem with the rate or rhythm of your heartbeat caused by changes in your heart’s normal sequence of electrical impulses. Your heart may beat too quickly, called tachycardia; too slowly, bradycardia; or with an irregular pattern. Dysrhythmias can range from complete...

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Electrocardiogram Examination

By: Administrator, Views: 10588

An electrocardiogram (ECG or EKG) is a test that checks how your heart is functioning by measuring the electrical activity of the heart. With each heartbeat, an electrical impulse (or wave) travels through your heart. This wave causes the muscle to squeeze and pump blood from the heart. Sinoat...

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Spermatogenesis Animation

By: Administrator, Views: 11099

Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubules. These cells are called spermatogonial stem cells. T...

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Causes of Angina

By: Administrator, Views: 11161

Angina is a type of chest pain caused by reduced blood flow to the heart. Angina (an-JIE-nuh or AN-juh-nuh) is a symptom of coronary artery disease. Angina, which may also be called angina pectoris, is often described as squeezing, pressure, heaviness, tightness or pain in your chest.

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Electrical changes in the heart

By: HWC, Views: 7587

• 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). ...

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Automated external defibrillator (AED)

By: Administrator, Views: 10802

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...

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Blood Pressure Measurement

By: Administrator, Views: 10673

How nurses check a patient's blood pressure. Blood Pressure The pressure exerted by the blood on the walls of the arteries. Higher (systolic) number: the pressure while the heart contracts. Lower (diastolic) number: the pressure when the heart relaxes between beats. Measured by a sphygmoma...

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Depolarization of the SA node, Action potentials of the myocardium & ANS effects

By: HWC, Views: 7638

• A typical contractile cell in the myocardium has a resting membrane potential. • The resting membrane potential of cells in the SA node is not fixed, and is known as the pacemaker potential. • The action potential of a healthy SA nodal cell has three parts: • Pacemaker potential: ...

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