Name the factors on which shape of the cells depends?

Cells are the basic unit of life and many cells together for an organ which performs a particular function. The shape of the cell usually depends on the function that the cells have to perform. For example, the muscles cells have a spindle shape to help them contract and relax, the sperm cells have a small head and a tail that helps them to swim , the RBCs have a circular doughnut shape to pass through the blood vessels easily and to carry more oxygen with them