1. The Muscular System

2. Did you know that ? -more than 50% of body weight is muscle ! -And muscle is made up of proteins and water

4. The Muscular System Muscles are responsible for all movement of the body There are three basic types of muscle –Skeletal –Cardiac –Smooth

5. Info About Muscles Only body tissue able to contract create movement by flexing and extending joints Body energy converters (many muscle cells contain many mitochondria)

6. 3 Types of Muscles

7. Three types of muscle SkeletalCardiacSmooth

8. Classification of Muscle Skeletal- found in limbs Cardiac- found in heart Smooth- Found in viscera Striated, multi- nucleated Striated, 1 nucleus Not striated, 1 nucleus voluntaryinvoluntary

9. Characteristics of Muscle Skeletal and smooth muscle are elongated Muscle cell = muscle fiber Contraction of a muscle is due to movement of microfilaments (protein fibers) All muscles share some terminology –Prefixes myo and mys refer to muscle –Prefix sarco refers to flesh

10. Shapes of Muscles Triangular- shoulder, neck Spindle- arms, legs Flat- diaphragm, forehead Circular- mouth, anus

11. Skeletal Muscle Most are attached by tendons to bones Cells have more than one nucleus (multinucleated) Striated- have stripes, banding Voluntary- subject to conscious control Tendons are mostly made of collagen fibers Found in the limbs Produce movement, maintain posture, generate heat, stabilize joints

12. Structure of skeletal muscle Each cell (fibre) is long and cylindrical Muscle fibres are multi-nucleated Typically 50-60mm in diameter, and up to 10cm long The contractile elements of skeletal muscle cells are myofibrils

13. Skeletal muscle - Summary Voluntary movement of skeletal parts Spans joints and attached to skeleton Multi-nucleated, striated, cylindrical fibres

14. Smooth Muscle No striations Spindle shaped Single nucleus Involuntary- no conscious control Found mainly in the walls of hollow organs

15. Smooth muscle Lines walls of viscera Found in longitudinal or circular arrangement Alternate contraction of circular & longitudinal muscle in the intestine leads to peristalsis

16. Structure of smooth muscle Spindle shaped uni-nucleated cells Striations not observed Actin and myosin filaments are present( protein fibers)

17. Smooth muscle - Summary Found in walls of hollow internal organs Involuntary movement of internal organs Elongated, spindle shaped fibre with single nucleus

18. Cardiac Muscle Striations Branching cells Involuntary Found only in the heart Usually has a single nucleus, but can have more than one

19. Cardiac muscle Main muscle of heart Pumping mass of heart Critical in humans Heart muscle cells behave as one unit Heart always contracts to it’s full extent

20. Structure of cardiac muscle Cardiac muscle cells (fibres) are short, branched and interconnected Cells are striated & usually have 1 nucleus Adjacent cardiac cells are joined via electrical synapses (gap junctions) These gap junctions appear as dark lines and are called intercalated discs

21. Cardiac muscle - Summary Found in the heart Involuntary rhythmic contraction Branched, striated fibre with single nucleus and intercalated discs

22. Muscle Control Type of muscle Nervous control Type of control Example Skeletal Controlled by CNS Voluntary Lifting a glass Cardiac Regulated by ANS Involuntary Heart beating Smooth Controlled by ANS Involuntary Peristalsis- (digestion)

23. Contraction and relaxation (pulling/Shorting) How do they Work? Kind of like the Opposite of how rubber bands work.

24. Types of Responses Twitch- –A single brief contraction –Not a normal muscle function Tetanus –One contraction immediately followed by another –Muscle never completely returns to a relaxed state –Effects are compounded

25. Types of Responses Twitch- –A single brief contraction –Not a normal muscle function Tetanus –One contraction immediately followed by another –Muscle never completely returns to a relaxed state –Effects are compounded

26. Types of Responses Twitch- –A single brief contraction –Not a normal muscle function Tetanus –One contraction immediately followed by another –Muscle never completely returns to a relaxed state –Effects are compounded

27. Exercise and Muscles Isotonic- muscles shorten and movement occurs ( most normal exercise) Isometric- tension in muscles increases, no movement occurs (pushing one hand against the other)

28. How are Muscles Attached to Bone? Origin-attachment to a movable bone Insertion- attachment to an immovable bone Muscles are always attached to at least 2 points Movement is attained due to a muscle moving an attached bone

29. Muscle Attachments Origin Insertion

30. Bro, do you even lift?

31. Flexion DECREASES ANGLE BETWEEN BONES

32. Extension INCREASES ANGLE BETWEEN BONES

33. Hyperextension MOVEMENT GREATER THAN 180 DEGREES

34. Abduction &Adduction ABDUCTION – MOVE AWAY FROM THE MIDLINE ADDUCTION – MOVE TOWARD MIDLINE

35. CIRCUMDUCTION ABDUCTION – MOVE AWAY FROM THE MIDLINE ADDUCTION – MOVE TOWARD MIDLINE

36. Rotation Rotation is turning a bone on its own axis

37. More Types of Movement…… Inversion- turn sole of foot medially Eversion- turn sole of foot laterally Pronation- palm facing down Supination- palm facing up Opposition- thumb touches tips of fingers on the same hand

38. The Skeletal Muscles There are about 650 muscles in the human body. They enable us to move, maintain posture and generate heat.

39. END ?.

40. Sternocleidomastoideus Flexes and Rotates Head

41. Masseter Elevate Mandible

42. Temporalis Elevate & Retract Mandible

43. Trapezius Extend Head, Adduct, Elevate or Depress Scapula

44. Latissimus Dorsi Extend, Adduct & Rotate Arm Medially

45. Deltoid Abduct, Flex & Extend Arm

46. Pectoralis Major Flexes, adducts & rotates arm medially

47. Biceps Brachii Flexes Elbow Joint

48. Triceps Brachii Extend Elbow Joint

49. Rectus Abdominus Flexes Abdomen

50. External Oblique Compress Abdomen

51. External Intercostals Elevate ribs

52. Internal Intercostals Depress ribs

53. Diaphragm Inspiration

54. Forearm Muscles Flexor carpi—Flexes wrist Extensor carpi—Extends wrist Flexor digitorum—Flexes fingers Extensor digitorum—Extends fingers Pronator—Pronates Supinator—Supinates

55. Gluteus Maximus Extends & Rotates Thigh Laterally

56. Rectus Femoris Flexes Thigh, Extends Lower Leg

57. Gracilis Adducts and Flexes Thigh

58. Sartorius Flexes Thigh, & Rotates Thigh Laterally

59. Biceps Femoris Extends Thigh & Flexes Lower Leg

60. Gastrocnemius Plantar Flexes Foot & Flex Lower Leg

61. Tibialis Anterior Dorsiflexes and Inverts Foot