The Muscular System

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 flexingand extendingjoints • Body energyconverters (many muscle cells contain many mitochondria)

7. 3 Types of Muscles

8. Skeletal Cardiac Smooth Three types of muscle

9. Classification of Muscle

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. Type of muscle Nervouscontrol Type of control Example Controlled by CNS Voluntary Lifting a glass Regulated by ANS Involuntary Heart beating Controlled by ANS Involuntary Peristalsis Muscle Control Skeletal Skeletal Cardiac Smooth

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

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 MusclesThere 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