The muscular system has four key characteristics: excitability, contractility, extensibility, and elasticity. These characteristics allow muscles to perform important functions like movement, maintaining posture, supporting soft tissues, and regulating body temperature. There are three main types of muscle in the body: cardiac, smooth, and skeletal. Skeletal muscle is responsible for all body movements and attaches to bones via tendons. It comprises around 30-35% of total body mass in women and 42-47% in men.

1. Muscular
System

2. There are four characteristics associated with
muscle tissue:
 Excitability - Tissue can receive & respond to
stimulation
 Contractility - Tissue can shorten & thicken
 Extensibility - Tissue can lengthen
 Elasticity - After contracting or lengthening,
tissue always wants to return to its resting
state
Functions

3. The characteristics of muscle tissue enable it to
perform some important functions, including:
 Movement – both voluntary & involuntary
 Maintaining posture
 Supporting soft tissues within body cavities
 Maintaining body temperature
Functions

4. The Muscular System
 Muscles are responsible for all types of
body movement – they contract or
shorten and are the machine of the
body
 Three basic muscle types are found in
the body, what are they?

5. 3 Types of Muscle
 The human body is comprised of 324 muscles
 Muscle makes up 30-35% (in women) and 42-
47% (in men) of body mass
Cardiac
Smooth
Skeletal

6. Characteristics of Muscles
 Muscle cells are elongated
(muscle cell = muscle fiber)
 Contraction of muscles is due to the
movement of microfilaments
 All muscles share some terminology
Prefix myo refers to muscle
Prefix mys refers to muscle
Prefix sarco refers to flesh

7. Anatomy of skeletal muscles
Skeletal
muscle
fiber (cell)
Muscle
Fascicle
Surrounded by
perimysium
Surrounded by
endomysium
endomysium
perimysium
Skeletal
muscle
Surrounded by
epimysium
epimysium
tendon

8. Muscle Fascicle
Muscle fibre
Myofibril
Actin
Myosin

9. Major Muscles (anterior)

10. Major Muscles (anterior)

11. Major Muscles (anterior)

12. Major Muscles (anterior)

13. Major Muscles (anterior)

14. Rectus Femoris Actions: flex hip, extend knee (two joint muscle)
Vastus Lateralis
Vastus Intermedius Action: extend knee (single joint muscle)
Vastus Medialis
Rectus Femoris
Origin – inferior pelvis
Vastus Lateralis
Vastus Intermedius
Vastus Medialis
Origin – proximal
femur
Major Muscles (anterior)

15. Major Muscles (anterior)

16. Pubic symphysis
Major Muscles (anterior)

17. Major Muscles (anterior)

18. Major Muscles (anterior)

19. Major Muscles (posterior)

20. Major Muscles (posterior)

21. Olecranon
process
Major Muscles (posterior)

22. Major Muscles (posterior)

23. Medial
Hamstrings
Lateral
Hamstrings
Major Muscles (posterior)

24. Two Joint Muscle
Major Muscles (posterior)

25. One Joint Muscle
Major Muscles (posterior)