1. The Human Muscular system
PSE4U: Unit 3

2. Learning Objectives Discuss functions of the muscular system
Examine muscle fibre types
Become familiar with types of muscular contractions
3 basic types of contraction

3. 7 Functions of the Muscular System
Shape
Posture
Movement
Function of vital organs (heart, respiration, digestion etc.)
Communication
Support and Protect organs
Maintenance of body temperature

4. Types of Muscle The human body is comprised of ~700 muscles
Muscle makes up 30-35% (in women) and 42-47% (in men) of body mass.
Three types of muscle:
Skeletal muscle
Smooth muscle
Cardiac muscle

5. Muscle Cell types

6. CLASSIFICATION OF MUSCLES SUMMARY
1. Location
2. Microscopic Appearance
3. Nervous Control
A. Skeletal
A. Striated
A. Voluntary
B. Visceral
B. Smooth
B. Involuntary
C. Cardiac
C. Syncytium
C. Vol/Invol

7. A. Skeletal (Striated) Muscle
Makes up 30-40% of body mass
Connects the various parts of the skeleton through one or more connective tissue tendons
During muscle contraction, skeletal muscle shortens and moves various parts of the skeleton
Through graded activation of the muscles, the speed and smoothness of the movement can be gradated
Activated through signals carried to the muscles via nerves (SNS - voluntary control)
Repeated activation of a skeletal muscle can lead to fatigue
Produces heat (temperature regulation)

8. Skeletal (striated) Muscle

9. B. Smooth Muscle
Located in the blood vessels, the respiratory tract, the iris of the eye, the gastro-intestinal tract
The contractions are slow and uniform
Functions to alter the activity of various body parts to meet the needs of the body at that time
Is fatigue resistant
Activation is involuntary (ANS)

10. Smooth Muscle

11. C. Cardiac Muscle
Has characteristics of both skeletal and smooth muscle
Specialized – allows for synchronous contractions
Functions to provide the contractile activity of the heart
Contractile activity can be gradated (like skeletal muscle)
Is very fatigue resistant
Activation of cardiac muscle is involuntary (like smooth muscle)

13. Structural Differences of Muscle Cells

14. Static vs. Dynamic Muscle Contractions
**no visible movement occurs**
muscle force is equal to load (holding something up without moving it ie. Hanging a picture)
The need for a maximal static contraction is rare in sports
Eg. Wresting, judo, gymnastics
DYNAMIC
**visible movement of the load**
Muscle forces changes as the load is moved

15. 3 Basic Types of Muscular Contractions
ISOMETRIC CONTRACTION
No visible movement at the joint (static)
No change in muscle length
CONCENTRIC CONTRACTION
Shortening of muscle fibres
Visible movement of a joint (dynamic)
ECCENTRIC CONTRACTION
Lengthening of muscle fibres
Visible movement at a joint (dynamic)