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How the Heart Works

on October 16, 2019

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THE SPINAL CORD.

The spinal cord consist of thousand of neurons clustered to form a cylindrical nervous tissue. It runs down the length of the neural canal formed by the stacking of the vertebrae, and hence occupies a dorsal position in the animals body. The spinal cord is enveloped within three membranes: The Meninges ; which support and protects it. The Spinal Canal; a narrow canal which runs down the centre of the cord. The cerebrospinal fluid. A transverse section of the spinal cord shows a greyish central region, the grery matter, surrounded by a lighter region, the white matter. T he grey matter is composed of practically all the cell body of the neurones in the spinal cord. Since the cell body are dense and granular, they give this region it's typically greyish appearance. The white matter consists of the nerve fibres of these cell bodies. Some of...

The Human Heart.

The human heart is a conical, hollow, muscular organ which works continuously throughout the life of a person. It is about the size of a clenched fist and weighs 300 grams. The heart lies in the chest just behind the breastbone and between the two lungs. It is enveloped in a two-layered tough membranous bag, the pericardium . The space between the two-layer is filled with fluid, This reduces the friction caused by the pumping movements of the heart, between the heart wall and the surrounding tissues. when at rest the average human heart contracts and relaxes about 70 times per minute and pumps about 14 liters of blood a day. During exercise this rate goes up to over 100 thereby increasing the supply of oxygen and food to the body cells. To carry out such hard work the wall of the heart is made up of a special muscle, the cardiac muscle found only in the heart. It contracts and relaxes rhythmically, and can ...

Energy

Energy is often defined as the ability to do work. It exists in different forms such as : 1; Potential or stored energy. 2; Kinetic energy or energy in motion. 3; Heat or thermal energy. 4; Light energy 5; Electrical energy. 6; Sound or vibrational energy. 7; Chemical energy. 8; Nuclear energy. Various forms of energy are interconvertible, for example: The food we eat pcontains chemical energy. But, inside our body this energy is changed to heat energy that warm's our body and to kinetic energy that enables us to do work. Also we are not the only ones that can convert energy other things around us are also capable of doing such for instance an electric bulb convert's electrical energy to heat and light energy. In fact all matter possess energy in one form or the other. ------------Note the following's ------------- 1; Energy can neither be created nor destroyed, but can be created from one form to another. 2; The commonest form of energy cha...

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How the Heart Works

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