1. The Muscular System

2. or “Everything you ever wanted to know about Muscles, but were afraid to ask” !!!

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

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

6. 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)

7. 3 Types of Muscles

8. Three types of muscle SkeletalCardiacSmooth

9. 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

10. 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

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

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

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

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

15. 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

16. 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

17. Where Does the Energy Come From? Energy is stored in the muscles in the form of ATP ATP comes from the breakdown of glucose during Cellular Respiration This all happens in the Mitochondria of the cell When a muscle is fatigued (tired) it is unable to contract because of lack of Oxygen

18. Flexion Decreasing the angle between 2 bones or bending a limb at a joint Types of Musculo-Skeletal Movement

19. Extension Increasing the angle between 2 bones or straightening out a limb

20. Hyperextension Extreme or overextension of a limb or body part beyond its normal limit.

21. Abduction, Adduction & Circumduction Abduction: movement away from the midline of the body. Adduction: movement toward the midline of the body. Circumduction: turns toward the far end.

22. Rotation Circular movement around an axis

23. The Skeletal Muscles There are about 650 muscles in the human body. They enable us to move, maintain posture and generate heat. In this section we will only study a sample of the major muscles.

24. Sternocleidomastoid Flexes and Rotates Head

25. Masseter Elevate Mandible

26. Temporalis Elevate & Retract Mandible

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

28. Latissimus Dorsi Extend, Adduct & Rotate Arm Medially

29. Deltoid Abduct, Flex & Extend Arm

30. Pectoralis Major Flexes, adducts & rotates arm medially

31. Biceps Brachii Flexes Elbow Joint

32. Triceps Brachii Extend Elbow Joint

33. Rectus Abdominus Flexes Abdomen

34. External Intercostals Elevate ribs

35. Internal Intercostals Depress ribs

36. Diaphragm Inspiration

37. Gluteus Maximus Extends & Rotates Thigh Laterally

38. Gastrocnemius Plantar Flexes Foot & Flex Lower Leg