1. BODY ORGANIZATION AND HOMEOSTASIS
Key Concepts:
What are the levels of organization in the body?
What is homeostasis?

2. Key Terms Cell Connective tissue Cell membrane Epithelial tissue
Nucleus Organ
Cytoplasm Organ System
Tissue Homeostasis
Muscle tissue Stress
Nervous tissue

3. Cells Basic unit of structure and function in a living thing
Human body contains about 100 trillion cells
Structure of cells – all animal cells contain cell membrane, nucleus and cytoplasm
Function of cells – release energy from food, grow and reproduce and get rid of wastes

4. Tissues Group of similar cells that perform the same function
Four types:
Muscle – can contract or shorten, make body move
Nervous – carry electrical signals between brain and other body parts
Connective – provides support for body and connects all parts
Epithelial – covers surfaces of body both inside and out

5. Organs and Organ Systems
Organs - structures composed of different types of tissues – performs a specific job, more complex than tissue
Organ Systems – group of organs that work together to perform a major function

6. Major Organ Systems of the Human Body
Circulatory
Digestive
Nervous
Skeletal
Endocrine
Muscular
Excretory
Respiratory

7. Homeostasis
Process by which an organism’s internal environment is kept stable in spite of changes in the external environment
All systems of the body work together to maintain homeostasis
Examples
– body temperature – stays close to 37°C whatever the outside temperature
- Sweating to cool off and shivering to get warm

8. Stress and Homeostasis
Stress - The reaction of your body to potentially threatening, challenging or disturbing events. Throws off homeostasis
Example – Bike Race – heart beats faster, breathing increases, adrenaline is pumped into your bloodstream.
At the end of the race – all quickly return to normal