1. The Muscular System

2. Muscular System  The body has more than 600 muscles that make up 40 to 45% of the body’s weight

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

4. Cardiac Muscle  Indistinctly striated  Involuntary  Under control of the autonomic nervous system

5. Smooth Muscle  Visceral  Unstriated  No dark and light bands  Involuntary

6. Smooth Muscle  Located:  Walls of internal organs  Respiratory and digestive tracts  Digestive tract=peristalsis  Wavelike movement  Causes contents to be propelled onward

7. Muscle Function

8.  Aid in movement of:  Body  Blood  Food  Waste  Provide and maintain posture  Protect internal organs  Provide heat

9. How Muscles Are Named

10. How Muscles are Named MMMMuscle origin PPPPlace where muscle begins MMMMore fixed end nearest midline MMMMuscle insertion PPPPlace where muscle ends FFFFarthest from midline

11.  Size  Maximus  Minimus  Shape  Deltoid  Trapezius  Direction of fibers  Rectus  Oblique  Location  Anterior  Posterior  Bone  Number  Bi  Tri  Quad

12. Muscle Characteristics  Muscle tone or tonus  Partial state of contraction  Balanced muscle tension required to hold body in position  Flaccid  Soft when not contracted

13. Muscle Characteristics  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

14. Accessory Structures

15. Tendons  Strong, fibrous connective tissue that connect muscle to bone

16. Fascia  Fibrous membrane that covers, supports, and separates muscle

17. Types of Muscle Contractions  Fibrillation: uncoordinated contractions  Convulsions: contractions of groups of muscles in abnormal manner  Spasms: involuntary, sudden, prolonged  Twitch: quick, jerky movement

18. Rules for 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

19. 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  Plantar flexion: bending foot forward  Dorsiflexion: bending foot toward knee  Extension  Increase angle between two bones or straightening out a limb  Elbow straightened and lower arm downward

20. 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

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

22. Pathology of the Muscular System

23. Muscle atrophy  Weakening and wasting away of muscle tissue  Occurs with paralysis and other conditions  Can lead to contractures:  Joint remains in flexed position 

24. Muscular dystrophy  Genetic disease  Gradual atrophy of muscle tissue  No cure  Treatment:  Medication to slow  Braces  Corrective surgery

25. Muscular Dystrophy

26. Fibromyalgia  A group of muscle disorders affecting the tendons, ligaments, and other fibrous tissues  Common sites of pain  Neck, shoulders, thorax, lower back, thighs  Myalgia (pain) common  Treatment: reduce stress, therapy, exercise

27. Hernia  The abnormal protrusion of a body part into another body area  Result from weakness in stomach muscles  Treatment: bracing or surgery

28. Hernia

29. Poliomyelitis  A viral infection  Results in paralysis of muscles  Prevented by vaccination  No cure

30. Gangrene  Cause: bacterial infection  Destroy living tissue by toxin  Treatment:  Removal of dead tissue  Antibiotics  Meds against toxin

31. Pes planus  Flatfoot or fallen arches  Either congenital or from weakened foot muscles  May cause extreme pain

32. Tetanus  AKA “lock jaw”  Caused by a bacterial infection  Toxin causes sustained contractions  Prevention: immunization  No cure-palliative care of symptoms

33. Muscle Strain  Torn or stretched tendons or muscles

34. The End