1. Muscular & Skeletal Systems

2. Muscular System Muscles are the organs that move body parts.
Bones and joints
have no power to
move on their own.
More than 600
muscles in the body
35–40% of body mass
is muscle

3. Muscular System
Muscle—organ that contracts and becomes shorter or expands and becomes longer
Result = Body parts move, energy is used, and work is done.

4. Muscular System Two Groups of Muscles Voluntary—You can control these.
Arms, legs, hands, face
2. Involuntary—You can’t control
these; you don’t have to decide to
make these muscles work.
Muscles around the heart

5. Muscular System Three Types of Muscle Tissue 1. Skeletal Muscle
Most numerous in body
Looks striped (striated)
Attached to the bones by
tendons
Tendons—thick bands that pull on
the bone as the muscle contracts
Voluntary
Contract quickly, tire easily

6. Muscular System Three Types of Muscle Tissue (cont.) 2. Smooth Muscle
Involuntary
Found in: walls of stomach,
intestine, uterus, etc.
Contracts and relaxes slowly
No striations

7. Muscular System Three Types of Muscle Tissue (cont.) 3. Cardiac Muscle
Only found in heart
Involuntary
Has striations
Contracts 70 times per minute (heartbeat)

8. Muscles at Work Skeletal muscle movements are
results of pairs of muscles
working together.
One muscle contracts while
the other muscle relaxes.
Muscles always pull;
they never push.

9. Muscles at Work Results of Muscle Action Muscles contract
This produces thermal energy, and it uses chemical energy.
Thermal energy produces heat that helps keep body temperature constant.
Chemical energy is from glucose. (When glucose is used up, muscles are tired and need to rest.)

10. Muscles at Work Results of Muscle action (cont.)
Over time, muscles become larger or smaller, depending on how much work they do.

11. Skeletal System Made up of all of the bones in your body,
it is the framework
of the body.
Each bone in your body
is a living organ, made
of different tissues.
Cells in bones take in
food and use energy.

12. Skeletal System
Made up of all of the bones in your body, it is the framework of the body.
- Five Functions of Skeletal System
1. Framework gives shape &
support to the body.

13. Skeletal System
Made up of all of the bones in your body, it is the framework of the body.
Five Functions of Skeletal System
1. Framework gives shape
and support to the body.
2. Bones protect the
internal organs.

14. Skeletal System
Made up of all of the bones in your body, it is the framework of the body.
Five Functions of Skeletal System
1. Framework gives shape & support to the body.
2. Bones protect the internal organs.
3. Major muscles of the body
are attached to the
bones.

15. Skeletal System
Made up of all of the bones in your body, it is the framework of the body.
Five Functions of Skeletal System
1. Framework gives shape & support to the body.
2. Bones protect the internal organs.
3. Major muscles of the body are
attached to the bones.
4. Blood cells are formed
in red marrow of some
bones.

16. Skeletal System
Made up of all of the bones in your body, it is the framework of the body.
Five Functions of Skeletal System
1. Framework gives shape & support to the body.
2. Bones protect the internal organs.
3. Major muscles of the body are
attached to the bones.
4. Blood cells are formed in red
marrow of some bones.
5. Skeleton is a place where
major quantities of calcium
and phosphorus compounds
are stored.

17. Bones The adult skeleton has 206 bones (baby has 270).

18. Joints Any place where two or more bones meet Ligaments: tough
bands of tissue that
hold bones together
at the joints