There are many different cells in the body, and all of them are created to perform a specific duty or function. Here are some of the more commonly know cells:
The red blood cell. These are cells that are shaped like biconcave disks and they lack a nucleus and other common cell parts. Their duty is to deliver oxygen to other body parts via the blood flow in the circulatory system. They will pick up the oxygen from the lungs and then will release it while sqeezing through the capillaries. The cytoplasm of a red blood cell is rich in a chemical known as haemoglobin, which gives the blood its red colour and can bind oxygen to the cell.
Red blood cells are usually about six to eight microns in diameter.
The nerve cell, or neuron, is a cell that is electrically excitable and its function is to process and transmit information to the brain via electrical and chemical signalling. A typical nerve cell comprises a body, dendrites (filaments that arise from the cell body) and an axon (a special filament that also arises from the cell's body). Neurons are highly variable in size, and range from 4 microns to 100 microns.
The human egg cell is a gamete, or reproductive cell, that is produced by women in the ovaries. It is the largest cell in the human body, with a diameter of up to 120 microns and can be seen with the naked eye. When a sperm cell fuses with it, fertilisation occurs, and the fertilised egg becomes a zygote. It then starts to develop into a human foetus.
The sperm cell's name is derived from the Greek word sperma, meaning seed. It is an appropriate name, as the sperm is the seed that decides the sex of a baby after fertilasation of the egg cell. A sperm cell has a head, which contains a nucleus and chromosomes; many mitochondria, to aid in movement; and a tail that enables it to mive independently. Sperm cells have a head 5 microns by 3 microns, and a tail 41 microns long.
No comments:
Post a Comment