Levels of Organization

When building a city you start with bricks. Many bricks joined together make walls. Walls working together make a building. Many buildings make a city.

The human body is put together in a similar way.

Humans start with cells. Many cells joined together make tissue. Tissue working together make an organ. Many organs make an organ system.

Cells are the smallest living part of an organism. Some examples of cells in the human body are brain cells, lung cells and bone cells.

When cells of similar structure and function join together they form tissue. A group of brain cells is called brain tissue. A group of lung cells is called lung tissue. Bone cells joined together is called bone tissue.

When a group tissues that perform a specific function join together they form organs. Brain tissue comes together to make your brain. Your brain is an organ. Lung tissue comes together to make your lungs. Bone tissue comes together to make individual bones.

An organ system is a collection of organs working together to perform a specific job. Your brain is apart of the nervous system. Your brain, spinal cord and nerves work together to collect and process information. Your lungs are apart of the respiratory system along with the larynx, diaphragm and others help you breath. All of the bones in your body are apart of the skeletal system. Bones, cartilage, ligaments and tendons give your body structure and support.

From smallest to largest the parts of your body are cell, tissues organs and then organ systems.