1. Human Biology
The Muscular System

2. The Muscular System…
The muscular system allows body movement and maintains posture
Your body has more than 600 muscles
Your muscles work even when you are asleep

3. The Muscular System…
Most muscles, or muscle tissue, are composed of muscle fibers that run beside, or parallel to, one another
These muscle fibers are held together in bundles of connective tissue
Each muscle fiber is actually a single cylinder-shaped cell

4. The Muscular System…
The function of muscle tissue is to contract, or shorten

5. The Muscular System… Types of Muscles
There are three types of muscle tissue in the human body
Skeletal muscle
Smooth muscle
Cardiac muscle
Each type of muscle tissue has a characteristic structure and function

6. The Muscular System… Skeletal muscle Attaches to and moves bones
By contracting, skeletal muscle causes your arms, legs, head, and other body parts to move

7. The Muscular System…
Under a microscope, skeletal muscle appears banded, or striated
Skeletal muscle is also known as striated muscle

8. The Muscular System… Skeletal muscle moves only when you want it to
Voluntary muscle
Skeletal muscles react quickly when you want them to
Skeletal muscles tire easily

9. The Muscular System… Smooth muscle Has no bands-hence the name
Help control breathing, blood pressure, and the movements of the digestive system
Has no bands-hence the name
In general, smooth muscles can contract without your actively causing them to
Involuntary muscle

10. The Muscular System… Smooth muscles react slowly
Smooth muscles tire slowly

11. The Muscular System… Cardiac muscle
Found only in the heart
Branches out in many directions, weaving a complex mesh
Contractions of cardiac muscle cause the heart to beat

12. The Muscular System…
Cardiac Muscle
Involuntary muscle
Does not tire

13. The Muscular System… Action of skeletal muscles
Muscles do work only by contracting
In order for muscles to cause any kind of movement, they must work in pairs
Nerves carry messages from the brain and the spinal cord to the muscles, signaling them to contract

14. The Muscular System…
Injuries to the muscular system
Strain, tear

15. The Muscular System… Review
Muscle tissue is made of fibers bundled together by connective tissue
Muscle tissue moves only by contracting
There are 3 types of muscle tissue
Skeletal
Smooth
Cardiac

16. The Muscular System… Skeletal muscle Smooth muscle Cardiac muscle
Permits voluntary movement
Are connected to bone
Smooth muscle
Help control breathing, blood pressure, and movements in the digestive system
Cardiac muscle
Makes the heart beat

17. The Muscular System… All skeletal muscles work in pairs
When one contracts, the other relaxes