What is the body made of?

More than half of the human body is made of water. The rest of the body is built from a huge number of complicated chemicals. These chemicals, together with water, are assembled into tiny building blocks called cells. Each cell is self-contained and has a particular function in the body. There are more than 50,000 billion cells in your body.

 

 

 

 

 

 

 

 

What do cells look like?

The shape and appearance of a cell depends on what job it does. Nerve cells are long and thread-like so they can carry messages around the body along the nervous system. Red blood cells are like flattened discs that are pinched in at the centre. White blood cells are shapeless so they can squeeze between other cells and attack invaders such as bacteria.

 

 

 

 

 

 

 

What’s inside a cell?

Cells consist mostly of a watery jelly-like material called cytoplasm. Each cell is held together by a very thin flexible membrane, rather like a balloon filled with water inside the cell the cytoplasm is organized into special areas called organelles. These control the functioning of the cell, for example, the production of essential substances called proteins. Tiny grains called mitochondria use oxygen to break down food and release the energy that powers the cell. An area called the nucleus contains 46 thread-like chromosomes that control the working of the cell. Some cells, such as those lining the intestines, only live for a few days, while other nerve cells within the brain can survive throughout your entire life.

Pictures Credit: Google