1. Muscle Function

2. 3 Types of Muscle Tissue Skeletal muscle Smooth or Visceral Muscles
Cardiac muscle
The body has more than 600 muscles that make up 40 to 45% of the body’s weight

3. Skeletal Muscle Tissue
Striated
Dark and light bands in fibers
Voluntary
Conscious control over these muscles

4. Smooth or Visceral Muscle Tissue
Unstriated
No dark and light bands
Involuntary
Under control of the autonomic nervous system
Located:
Walls of internal organs
Respiratory and digestive tracts
Digestive tract=peristalsis
Wavelike movement
Causes contents to be propelled onward

5. Cardiac Muscles
Indistinctly striated
Involuntary

6. Muscle Function

7. Muscle Function Aid in movement Provide and maintain posture
Protect internal organs
Provide movement of blood, food and waste products
Open and close body openings
Provide heat
Muscle Function

8. Our Muscles

9. How Muscles are Named Muscle origin Muscle insertion
Place where muscle begins
More fixed end nearest midline
where movement does not occurs
Muscle insertion
Place where muscle ends
End where movement occurs
Farthest from midline
How Muscles are Named

10. How Muscles are Named Location Size Shape Number Direction of fibers
Anterior
Posterior
Bone
Number Bi
Tri
Quad
Size
Maximus
Minimus
Shape
Deltoid
Trapezius
Direction of fibers
Rectus
Oblique
How Muscles are Named

11. Characteristics of Muscles
Irritability
Ability to respond to stimulus
Contractibility
Ability to shorten
Extensibility
Ability to stretch and lengthen
Elasticity
Ability to return to original length at rest

12. Muscular System Flaccid Muscle tone or tonus Soft when not contracted
Normal state of balanced muscle tension required to hold body in awake position
Partial state of contraction
Muscles are ready for action
Muscular System

13. Flaccid and Tone

14. Tendons Strong, fibrous connective tissue that connect muscle to bone
Achilles tendon
Located bottom of the calf (gastrocnemius muscle)
Secures that muscle to heel of bone (calcaneus)

15. Fascia
Fibrous membrane that covers, supports, and separates muscle

16. Structures of Muscles Made of bundles of muscle fibers
Basic unit causing contraction: sarcomeres
made of actin & myosin myofibrils

18. Contraction of Muscles
Sliding filament theory
Contain bundles of muscle fibers
Single fiber:
Fibrils containing actin & myosin filaments
During contraction, actin & myosin filaments move close together to shorten muscle

19. Contraction of Muscles
Results from:
Myoneural stimulation
Glucose fuels ADP-ATP cycle for release of energy
Calcium needed for reaction to occur
Produces:
Muscle contraction
Heat
Lactic acid
Carbon dioxide & water
Contraction of Muscles

20. Types of Muscle Contractions
Isotonic: shortening produces movement
Isometric: does not produce shortening or movement
Twitch: quick, jerky movement
Tetanic contraction (tetany): sustained contraction caused by stimuli in rapid succession
Types of Muscle Contractions

21. Types of Muscle Contractions
Fibrillation: uncoordinated contractions
Convulsions: contractions of groups of muscles in abnormal manner
Spasms: involuntary, sudden, prolonged
Types of Muscle Contractions

22. Muscle Movement Pull never push on bones Always cross a joint
Work in pairs:
Prime mover (agonist): pulls to cause movement
Antagonist: relaxes when agonist pulls
Synergists & fixators:
keep muscle & bone stable during movement
Muscle Movement

23. Body Movements Caused by Skeletal Muscle
Flexion:
Decrease angle between two bones or bending a limb at a joint
Elbow bent and lower arm brought upward
Knee bent and lower leg backward
Extension
Increase angle between two bones or straightening out a limb
Elbow straightened and lower arm downward
Body Movements Caused by Skeletal Muscle

24. Body Movements Caused by Skeletal Muscle
Abduction
Movement away from body midline
Arm moves outward, away from side of body
Adduction
Movement toward midline of body
Arm moves inward, toward side of body
Rotation
Circular or semi-circular movement around an axis
Turning the head when saying no
Body Movements Caused by Skeletal Muscle

25. Body Movements Caused by Skeletal Muscle
Pronation:
Turning hand downward
Supination:
Turning hand upward
Body Movements Caused by Skeletal Muscle