1. Chapter 13:
Bones, Muscles,
and Skin

2. Body Organization and Homeostasis
Levels of organization in the body:
1. Cell
2. Tissue
3. Organ
4. Organ System
5. Organism
Specific
Broad

3. Cells
Remember cell structure and function (cell membrane, nucleus, cytoplasm)
Functions of cells
1. Undergo chemical reactions
2. Grow and reproduce
3. Get rid of wastes

4. Tissues A tissue is a group of cells that perform the same function.
Muscle Tissue- can contract or shorten
Nervous Tissue- directs and controls the body

5. Connective Tissue- supports your body and connects its parts.
Epithelial Tissue- covers the surfaces of your body (skin, digestive tract, etc.)

6. Organs and Organ Systems

7. Homeostasis Maintaining a stable internal body environment.
Your body temp is close to 98.6° no matter what the temp is outside.
When you are hot you sweat, when you’re cold you shiver.
Stress- your body’s reaction to potentially threatening events.

8. The Skeletal System
Your skeleton is made up of all of the bones in your body.
A newborn baby has about 275 bones.
An adult has about 206 bones.
As a baby grows, some of its bones fuse together.

9. Five major functions of the skeleton
Provides shape and support
Vertebrae- 26 bones of the spine
Enables movement
Protects organs
Produces blood cells
Stores minerals and other materials

10. Joints of the Skeleton
- The Skeletal System
A joint is a place in the body where two bones come together. Joints allow bones to move in different ways.

11. Ligaments- connect bones together
Cartilage- covers the ends of bones and keeps them from rubbing together.
Compact Bone- hard and dense
Spongy Bone- beneath compact bone, contains many small spaces

12. Marrow- soft connective tissue
1. Red Marrow- produces most of the body’s red blood cells. You have more red marrow as a child than as an adult.
2. Yellow Marrow- stores fat that can serve as energy reserves.

13. Bones—Strong and Living
- The Skeletal System
Bones are complex living structures that undergo growth and development.

14. Bone Care Eat a balanced diet and exercise
Osteoporosis- mineral loss in the bones; they get weak and easily break
To prevent osteoporosis, eat lots of calcium-rich foods!

16. The Muscular System
Involuntary Muscles- Muscles that you DON’T control (heartbeat, breathing, digestion)
Voluntary Muscles- muscles that you DO control (smiling, moving, talking)

17. Three Types of Muscle Tissue
Smooth Muscle
Skeletal Muscle
Cardiac Muscle

18. Skeletal Muscle Attached to bones Provide force for movement
Voluntary Muscles
Tendon- connective tissue that attaches muscle to bone
Striated muscle- skeletal muscle is called striated because the cells appear to be banded.

19. Smooth Muscle On the inside of many organs Involuntary muscle
Not striated

20. Cardiac Muscle Found only in your heart Involuntary muscle
Striated muscle
Never gets tired (good thing!)

21. Muscles at Work
- The Muscular System
Because muscle cells can only contract, not extend, skeletal muscles must work in pairs. While one muscle contracts, the other muscle in the pair relaxes to its original length.
Ex. Biceps & Triceps
Hamstrings & Quadriceps

22. The Skin Functions of the skin: Protects the body from injury,
infection, and water loss
Homeostasis
Eliminates wastes
Gathers info about environment
Produces vitamin D

23. Layers of the Skin
The Epidermis- outer layer, usually thin, no blood vessels or nerves
- Melanin- pigment that gives skin color
The Dermis- inner layer, has nerves and blood vessels
- Pores- openings in the skin
- Follicles- where hairs grow on the skin

24. The Epidermis
- The Skin
The skin is organized into two main layers: the epidermis and the dermis.

25. Caring for the Skin
Three simple habits can help keep your skin healthy:
1. Eat a healthy diet
2. Keep your skin clean and dry
3. Limit sun exposure
- Cancer- when body cells divide uncontrollably
- Wear hat, sunglasses, and sunscreen
- Don’t go out between 10am & 4pm