Cell is the smallest unit in our body,it is the smallest living unit that can carry out the basic functions of life like growth, metabolism, and reproduction.All these cells grew from a single cell made when a sperm cell from father met an egg cell of mother.
Even though subatomic particles are the tiniest in the human body, they lack four capacities that distinguish the living from the non-living. Scientist defines living units as able to do these things, react to stimulate, transform nutrients in to energy, grow, and produce. Thus cells are the smallest living body components.
Except for the human egg, this can be seen with the naked eye as about the size of a dot. cells are microscopic. Most cells are measured in micrometers. a never cell may be a meter (approx 3 feet ) long, and a muscles cell may measure 25 millimeters (1 inch), single cells are so fine as to be invisible. Some cells look like columns, some like cubes, some like spheres, nerve cells look like threads, cheek cells suggest flat paving stones.
Cells also vary in life span. Cells in the lining of the intestine die after a day and half , white blood cells after 13 days, red blood cells after 120 days, meanwhile nerve cells live for 100 years. While all cells have the capacity to produce, store, and utilize energy, different cells perform additional highly specialized functions. Heart cells obviously play a different roll than liver cells do, in other words there is a division of labour in the human body that are doing their job in a prescribed manner.
