BASICS OF HUMAN BODY…

The smallest structure found in living things is the cell. And trillions of them make up each human body. These are the building blocks each having a specific job. They constantly divide themselves to produce new daughter cells which allow the body to grow and repair itself.

Definition of cell ( small room ):- the structural and functional unit of living body

Inside a cell

The body is made of trillions of cells,each too small to see with naked eyes. These cells aren’t all same. There are different types of cells which are about 200,each with it’s own size,shape and contents,each type of cell has a particular task.

Types of cell

Each type of cell has a shape,size related to its own task in the body

These cells are small,round,biconcave or doughnut shaped,and this lets them pick up and carry oxygen easily,in other words optimizes the ratio of surface area to volume, facilitating gas exchange. And helps them to fold up as they move from narrow blood vessels.

These are electrically excitable cells. Which carry electrical signals over long distances, and communicate with other cells via specialised connections called synapses. These are primary cells of nervous system.

These are in the skin fit tightly together to form a protective layer. These perform barrier function in human body. Protecting against bacteria and foreign particles and regulating amount of water released from body.

These cells can contract (shorten) and relax to produce movement.

These are filled with droplets of liquid fat as an energy store.

These cells are present in the retinas of human eye. They detect light enabling us to see. These cells perform best in bright light.

Like this, there are so many types of cells, these were few examples.

Facts

1. There are approximately 37 trillion (37000000000000) number of cells in human body.
2. It would take 1 million years to count all the body’s cells at a rate of one per second.
3. Red blood cells take up about 70% of the total number of cells in the body.