2. MUSCLE
Dr Iram Tassaduq

3. CHARACTERISTICS
CONTRACTILITY – long cells shorten and generate pulling forces
EXCITABILITY – electrical nerve impulse stimulates the muscle cell to contract
EXTENSIBILITY – can be stretched back to its original length by contraction of an opposing muscle (agonist / antagonist relationship)
ELASTICITY – can recoil after being stretched

4. FUNCTIONS
MOVEMENT (e.g. skeletal muscle moves body by moving the bones)
TRANSPORT fluids and other substances through hollow organs (smooth muscle)
MAINTENANCE OF POSTURE – enables the body to remain sitting or standing
JOINT STABILIZATION
HEAT GENERATION – muscle contractions produce heat (“shivering”) to help maintain normal body temperature
ALLOWS BREATHING TO OCCUR - e.g. the diaphragm contracts and relaxes to enable air to enter and exit the lungs

5. CLASSIFICATION OF MUSCLES
Morphological classification (based on structure)
1. Striated
2. Non striated or smooth.
Functional classification
1. Voluntary
2. Involuntary.

6. CLASSIFICATION OF MUSCLES
On the basis of appearance of contractile cells
STRIATED MUSCLES
Skeletal muscles
Cardiac muscles
NON-STRIATED MUSCLES
Smooth muscles

7. CLASSIFICATION OF MUSCLES
VOLUNTARY
Skeletal muscles except diaphragm
INVOLUNTARY
Cardiac muscle
Smooth muscle

8. TYPES OF MUSCLE Skeletal muscle: which is striated and voluntary
Cardiac muscle: which is striated and involuntary
Smooth muscle: which is non striated and involuntary

11. Skeletal muscles
Cardiac muscles
Smooth muscles

12. CARDIAC MUSCLE

13. SMOOTH MUSCLE

14. TERMS RELATED TO MUSCLES
Origin
Insertion
Belly
Tendon
Aponeurosis

15. ORIGIN
Attachment that moves the least

16. INSERTION
Attachment that moves the most

17. BELLY
It is the fleshy part of muscle

18. TENDON
It is a cord of fibrous tissue through which muscles are attached to bones or cartilage

19. APONEUROSIS
Strong thin sheet of fibrous tissue giving attachment to flat muscles

20. RAPHE
Interdigitation of tendinous ends of flat muscles

21. CONNECTIVE TISSUE ASSOCIATED WITH MUSCLES
ENDOMYSIUM
Layer of connective tissue surrounding each muscle fiber
PERIMYSIUM
Connective tissue layer of around each bundle of muscle fibers
EPIMYSIUM
Sheath of dense connective tissue surrounding whole muscle

22. CONNECTIVE TISSUE ASSOCIATED WITH MUSCLES

23. CLASSIFICATION OF SKELETAL MUSCLES
Shape of muscles
Direction of fibers
Action

25. CLASSIFICATION ON BASIS OF SHAPE

27. PENNATE MUSCLES
Pennate muscles have bellies that are attached to a central tendon.
Unipennate
Bipennate
Multipennate

30. CLASSIFICATION ON BASIS OF ACTION
Prime movers
Antagonist
Synergist
Fixator

31. PRIME MOVERS
Muscle which initiates a particular movemevt

33. ANTAGONIST
Any muscle that opposes action of prime mover

34. FIXATORS
Stabilize origin of prime mover so that it can act efficiently. These muscles contract isometrically

35. SYNERGISTS
When the prime movers cross more than one joint, the undesired actions at the proximal joints are prevented by certain muscles known as synergists. For example, during making a tight fist by long digital flexors the wrist is kept fixed in extension by the synergists (extensors of wrist).