PPT On Heart Anatomy and Physiology

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Heart Anatomy and Physiology Presentation Transcript:
1.Heart Anatomy and Physiology

2.The heart is a hollow muscle that pumps blood
throughout the blood vessels by repeated, rhythmic contractions. It is found in all animals with a circulatory system(including all vertebrates)

3.The average human heart, beating at 72 beats per minute, will beat approximately 2.5 billion times during an average 66 year lifespan. It weighs approximately 250 to 300 grams (9 to 11 oz) in females and 300 to 350 grams (11 to 12 oz) in males.

4.The term cardiac (as in cardiology) means "related to the heart" and comes from the Greek ?a?d??, kardia, for "heart".
The vertebrate heart is principally composed of cardiac muscle and connective tissue. Cardiac muscle is an involuntary striated muscle tissue found only in this organ and responsible for the ability of the heart to pump blood.

5.Structure
It is enclosed in a double-walled protective sac called the pericardium. The superficial part of this sac is called the parietal pericardium. The inner pericardium layer is called the visceral pericardium. Together they are usually called the serous pericardium because they contain the pericardial fluid. Outside the parietal pericardium there is a fibrous layer which depends from the mediastinal fascia and is called the fibrous pericardium.[13] The pericardium sac protects the heart, anchors its surrounding structures, but has no effect over the heart function in normal individuals.[14]
The double membrane of pericardium contains the pericardial fluid which provides a smooth lubricated sliding surface within which the heart organ can move in response to its own contractions and to movement of adjacent structures such as the diaphragm and lungs.[15]

6.The outer wall of the human heart is composed of three layers. The outer layer is called the epicardium, or visceral pericardium since it is also the inner wall of the (serous) pericardium. The middle layer of the heart is called the myocardium and is composed of muscle which contracts. The inner layer is called the endocardium and is in contact with the blood that the heart pumps.[16] Also, it merges with the inner lining (endothelium) of blood vessels and covers heart valves.[17]

7.The human heart has four chambers, two superior atria and two inferior ventricles. The atria are the receiving chambers and the ventricles are the discharging chambers.
The pathways of blood through the human heart are part of the pulmonary and systemic circuits. These pathways include the tricuspid valve, the mitral valve, the aortic valve, and the pulmonary valve.[18] The mitral and tricuspid valves are classified as the atrioventricular (AV) valves. This is because they are found between the atria and ventricles. The aortic and pulmonary semi-lunar valves separate the left and right ventricle from the pulmonary artery and the aorta respectively. These valves are attached to the chordae tendinae (literally the heartstrings), which anchors the valves to the papilla muscles of the heart.
The interatrioventricular septum separates the left atrium and ventricle from the right atrium and ventricle, dividing the heart into two functionally separate and anatomically distinct units.

8.Functioning
Blood flows through the heart in one direction, from the atria to the ventricles, and out of the great arteries, or the aorta for example. Blood is prevented from flowing backwards by the tricuspid, bicuspid, aortic, and pulmonary valves.
The heart acts as a double pump. The function of the right side of the heart (see right heart) is to collect de-oxygenated blood, in the right atrium, from the body (via superior and inferior vena cavae) and pump it, via the right ventricle, into the lungs (pulmonary circulation) so that carbon dioxide can be dropped off and oxygen picked up (gas exchange). This happens through the passive process of diffusion.

9.    The left side (see left heart) collects oxygenated blood from the lungs into the left atrium. From the left atrium the blood moves to the left ventricle which pumps it out to the body (via the aorta).
10.On both sides, the lower ventricles are thicker and stronger than the upper atria. The muscle wall surrounding the left ventricle is thicker than the wall surrounding the right ventricle due to the higher force needed to pump the blood through the systemic circulation. Atria facilitate circulation primarily by allowing uninterrupted venous flow to the heart, preventing the inertia of interrupted venous flow that would otherwise occur at each ventricular systole.[19]

11.    Starting in the right atrium, the blood flows through the tricuspid valve to the right ventricle. Here, it is pumped out of the pulmonary semilunar valve and travels through the pulmonary artery to the lungs. From there, blood flows back through the pulmonary vein to the left atrium. It then travels through the mitral valve to the left ventricle, from where it is pumped through the aortic semilunar valve to the aorta and to the rest of the body. The (relatively) deoxygenated blood finally returns to the heart through the inferior vena cava and superior vena cava.

12.Lifestyle and heart health
Obesity, high blood pressure, and high cholesterol can increase the risk of developing heart disease. However, half the number of heart attacks occur in people with normal cholesterol levels. Heart disease is a major cause of death.
It is generally accepted that factors such as exercise or the lack of it, good or poor diet, and overall well-being, including both emotional and physiological components, affect heart health in humans