1. Chap. 2 – The Muscular System

2. - Muscles that attached to bones
Skeletal Muscle
- Muscles that attached to bones
- Most prevalent
- VOLUNTARY – you make a conscious decision to flex
- Striated

4. Smooth Muscle Surround the body's internal organs
Contracts more slowly than skeletal muscle but can remain contracted for longer periods of time
INVOLUNTARY

6. Cardiac Muscle Only found in the heart
INVOLUNTARY – autonomic nervous system is responsible for making the muscle fibers contract
Muscle tissue is striated in appearance like skeletal muscle

8. To summarize...

9. The Neuromuscular System
Term referring to the link between the muscular system and the nervous system
Before a muscle contracts, a message needs to be sent from the brain
The neuromuscular junction is the point where the message from the brain meets the muscle

10. The Neuromuscular Junction

11. The Motor Unit
Muscle twitch: a single nervous impulse and the resulting contraction
Motor unit = the motor neuron, it's axon (pathway) and the muscle fibres it stimulates

12. The All-or-None Principle
The principle that states that when a motor unit is stimulated to contract, it will do so to its fullest potential
Example: if a motor unit consists of 50 muscle fibres and they are stimulated to contract, either all of the fibres will contract or none of them

13. Some educational videos...
How muscles contract:
muscle-cells-video.htm
Beating heart:
ature=related

14. Worksheet