1. Chapter 14: Bones, Muscles, and Skin
Key terms: Cell, cell membrane, nucleus, cytoplasm, tissue, muscle tissue, nervous tissue, connective tissue, epithelial tissue, organ, organ system, homeostasis, stress
Key concepts: what are the levels of organization within the body? What is homeostasis?

2. Levels of organization
Levels of organization in the body consists of cells, tissues, organs, and organ systems.

3. Cells! Yay we already know this!
Cells – basic units of structure and function in living things (memorize this statement, please, you will be happy you did for the rest of your biology-loving life)

4. Structure of cells
Cell membranes – forms the outside boundary of the cell.
Nucleus – control center that directs cells’ activities (CONTAINS GENETIC MATERIAL)
Cytoplasm – material within a cell that holds organelles. Clear, jellylike substance.

5. Functions of cells
Cells carry on processes that keep organisms alive. For example:
Molecules from digested food undergo chemical reactions that release energy for the body’s activities
Cells get rid of waste
Cells grow and reproduce

6. Tissues – The next unit of organization above cells (memorize THAT, too )
Tissue – group of similar cells that perform the same function.
The human body has four basic types of tissue – muscle, nervous, connective, epithelial

7. Muscle tissue
Like the muscle cells that form it, muscle tissue can contract, or shorten. This makes parts of your body move.

8. Nervous tissue
Nervous tissue directs and controls the process of movement. It carries electrical messages back and forth between the brain and other parts of the body.

9. Connective tissue
Connective tissue provides support for your body and connects all its parts. Examples are bones and fat.

10. Organs!

11. Organs!
An organ is a structure that is composed of different kinds of tissue. Like a tissue, and organ performs a specific job. Organs are a bit more complex though, and can contain more than 1 kind of tissue.
Examples: heart, lungs, skin, brain, liver, pancreas, etc

12. Organ systems (yes, you should know them all)
Organ system – group of organs that work together to perform a major function.
Circulatory – transports material to and from cells (blood, heart, veins, arteries)
Endocrine - controls processes with chemicals
Digestive – breaks down food
Muscular – muscles!
Nervous – brain, nerves, spinal cord,
Skeletal – bones
Respiratory – breathing (lungs, trachea)
Excretory – removes wastes

13. Homeostasis
Homeostasis is the process by which an organism’s internal environment is kept stable in spite of changes in the external environment
Example: internal body temperature

14. Stress
Stress – the reaction of your body to potentially threatening events
Endocrine system releases adrenaline, which gives you energy. Your heart beats faster, you receive more oxygen.
Why?
Fight or flight response 