1. The Levels of Organization
How is your body organized?

2. Your body is organized into levels- we call these levels, the levels of organization.
We start at the smallest unit and then go up to the largest unit.
The levels are
Cells
Tissues
Organs
Organ systems

3. Cells
A cell is the basic unit of structure and function in a living thing.
The human body consists of about 100 trillion cells
Cells carry on the processes that keep organisms alive- for instance, here is where molecules may be digested to provide energy

4. Tissue
A tissue is a group of similar cells that perform the same function.
The human body contains 4 basic types of tissue: muscle, nerve, connective and epithelial.

5. Organ
An organ is a structure that is composed of different kinds of tissue.
Like tissue, an organ performs a specific job.

6. Organ systems
A group of organs that work together to perform a major function.
There are 11 organ systems in the human body.
Can you name them?

7. All done!
Now watch the video, “Powers of 10” to observe the scale and structure of the world around us.