A cell is the smallest structural and functional unit of a living organism.
Every part of the human body is made up of cells. Some cells form tissues such as skin and muscle, while others circulate in the blood or help transmit nerve signals. Although cells have different shapes and functions, they all work together to keep the body alive and functioning properly.
Quick Fact
The human body contains trillions of cells, each carrying out specialised tasks.
See Also
- Tissue
- Organ
- Organ System