CELLS

Although the skin looks like a large sheet of materials, like every other part of the body it is in fact made up of countless tiny living cells. Cells are so small that we need a powerful microscope to see them. At the same time, they are very complex, and complicated activities go on in each one. Some parts of the body, such hair and nails, are made up of dead cells.

Different types of cells in the various parts of the body have different  jobs to do. The wide variety of cells in the body grow from just two cells, the sperm and the ovum, which joined together at fertilization.

Although the cells are not all the same, they all contain similar parts. Each cell has a control centre, the nucleus. This governs what goes on inside cell. Important information is also carried by the nucleus, including such things as hair and eye colour and a person’s sex. These characteristics are passed on when sperm and ovum join together at conception.

There are many kinds of cells in the body, each with its own job to do. Tissues are 1. Muscles

2. Epithelial tissue

3. Mucus

4. fat and

5 connective tissue cells.

·        the first person to see cells was an Englishman, Robert Hooke. Looking at a piece of cork under a microscope in 1663, he saw many ‘tiny boxes’ – the cells.

·        Millions of cells die all the time but are generally replaced by new ones which  the body makes. New cells form when an existing cell divides into two. Everything in cell splits, making each new cell identical.

·        The greatest part of  the cell is made up of cytoplasm. Inside are the various parts shown in the diagram above.