1. Levels of Organization and Organ Systems

2. Cells Most too small to be seen without microscope Over 200 types in human body Each does a specific job

3. Tissues Group of cells that work together to do a specific job Examples: blood, fat, muscle, etc.

4. Organs Two or more tissues working together Examples: stomach, liver, heart, etc. Are all organs made of the same kind of tissue? No. Every organ has different kinds of tissues to make it work.

5. Organ systems Groups of organs which work together to perform a job Each part depends on the others; if one fails, the whole system fails Example: digestive system, etc.

7. Organism Anything that can live on its own Made of at least one cell Single cell: unicellular More than one cell: Multicellular

9. Homeostasis Your organ systems are constantly working together to achieve homeostasis in your body. Homeostasis: maintaining a stable internal environment (for example: temperature – 98.6°, correct amount of blood and fluids, flow of blood, amount of oxygen to the cells, etc.) Describe 2 situations where your body would need to work to maintain homeostasis and how it would do so. (1. You are caught outdoors in the cold with no shirt or pants on, how would your body react to keep your temperature constant?)