1. Systems of the Body
7th Grade Science

2. 11 Body Systems Skeletal System Muscular System Cardiovascular System
Digestive System
Endocrine System
Nervous System
Respiratory System
Immune/Lymphatic Systems
Urinary System
Integumentary System
Reproductive Systems (Male and Female)

3. Skeletal System
The skeletal system is all of the bones in the body and the tissues (tendons, ligaments, and cartilage) that connect them.
Teeth are also considered part of the skeletal system, even though they are not made of bone.

5. What does the skeletal system do?
The skeletal system has three main jobs:
Support
Protection
Movement

6. Job #1: Support
The main job of the skeletal system is to give our bodies support
Without your bones your body would collapse into a pile on the floor, a puddle of skin and guts
The human skeleton is extremely strong for how light it is

7. Job #2: Protection
Your skeleton helps to protect your internal organs and other fragile tissues
Your skeleton protects your brain, eyes, heart, lungs, and very importantly your spinal cord
Your skull protects your brain and your eyes
Your ribs protect your heart and lungs
Your vertebrae (spine or backbone) protect your spinal cord

8. Job #3: Movement
Bones are what your muscles attach to so that they can move your body
Without bones your muscles would be useless!
Tendons are tough bands that attach your muscles to your bones
Tendons are not very flexible

10. Fun Facts Bones contain more calcium than any other organ
Bones stop growing in length in early adulthood but they can continue to increase in thickness throughout life due to increased weight
The adult skeleton has 206 bones, but babies have around 300 that fuse together during growth and development

12. Muscular System
The purpose of the muscles found in your body is to help your body move!
Muscles are responsible for everything from moving your legs when walking, to beating your heart, and even contracting tiny blood vessels inside of your brain
You have three different types of muscles in your body:
Skeletal
Cardiac
Smooth

13. Skeletal Muscle Tissue
Responsible for helping you move!
It is the only voluntary muscle tissue in your body, or the only one that you can control
This is why you can walk, run, smile, frown, etc.

14. Smooth Muscle Tissue Helps moves food and liquids throughout your body
Found in your blood vessels, bladder, and digestive system
These are involuntary, you don’t think about them to make them move

15. Cardiac Muscle Tissue
This muscle tissue is responsible for making your heart beat
It is found only in the heart
It is involuntary, after all, you don’t have to tell your heart to beat!

16. Muscles and Bones Working Together
Muscles need to connect to your bones to allow you to move
Tendons connect muscles to your bones at insertion points
Ligaments are connective tissue that bind bones to each other
Flexors are muscles that force your joints to bend (think biceps)
Extensors are muscles that make your limbs to straighten (think triceps)

17. Flexors vs. Extensors

18. Lab Time!