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The Heart. Structure of the Heart. Two parallel independent systems Two different “pumps” Each @ atrium (auricle) & ventricle Designating right cavity & left cavity as if you were “wearing” your heart.
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Structure of the Heart • Two parallel independent systems • Two different “pumps” • Each @ atrium (auricle) & ventricle • Designating right cavity & left cavity • as if you were “wearing” • your heart
Function of the Cavities • Right cavity takes in oxygen poor blood from the body • Pumps it to the lungs • Left cavity takes oxygen rich blood from the lungs • Returns it to the body
Functions of the Cavities • Atrium draws blood in from veins • Ventricle pushes blood away through arteries
Differences Between the Cavities • Right cavity takes in oxygen poor blood from the body & sends it to the lungs • Left cavity takes oxygen rich blood from the lungs and sends it to the body through the aorta. Its wall is thicker because it has to pump the blood throughout the body
How the Heart Works • There are two stages in the heart beat cycle • The diastole (relaxation) • The systole (contraction)
Diastole • In diastole the heart relaxes and blood goes into the two auricles • Rising pressure in each auricles opens the tricuspid and mitral valves and blood flows into the ventricles
Systole • Filled ventricles contract and the mitral and tricuspid valves close • The filled ventricles force the aorta and pulmonary valves to open • Blood is then pushed into the arteries
Rate of Heartbeat • The heart is a muscle is a unique muscle. • It has the ability to contract spontaneously at a regular rate of 80 beats per minute • That is what creates the pulse
Rate of Heartbeat • However this rate is influenced by two nervous systems: • Sympathetic • Parasympathetic
Sympathetic • This controls your heart by fear, and adrenaline. • For example when you get scared your heart intends to beat faster. • Your heart is also affected by exercise which is another aspect of the sympathetic nervous system
Parasympathetic • This nervous system controls your heart rate when you sleep • Your heartbeat is much slower when you sleep then when you are awake because of the function of this system
Heart Disease • The major form of heart disease is atherosclerosis • In this condition fatty deposits called plaques, composed of cholesterol and fats, build up on the inner wall of the coronary arteries
Heart Disease • Gradual narrowing of the arteries throughout life restricts the blood flow to the heart muscles. • Symptoms of this restricted blood flow can include: • shortness of breathe • and a tightening pain in the chest
Heart Disease • A heart attack is caused when oxygen supply to the heart is suddenly decreased by: • plaque large enough to completely obstruct the coronary artery • when part of the plaque breaks away and lodges farther along the artery
How to Prevent Heart Disease • Development of fatty plaque is due to excessive intake of cholesterol and animal fat and especially cigarette smoking • Evidence suggest that physical exercise may help to prevent heart disease and watching what you eat