Muscular system


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Lectures of Anatomy for Faculty of Nursing by Dr. Noura El Tahawy

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Muscular system

  1. 1. Muscular System By Dr. Noura El Tahawy
  2. 2. Function: 1) movement 2) maintain posture 3) joint stability 4) generate heat Muscles
  3. 3. Movements of Muscles
  4. 4. Movements of Muscles • Extension: increasing angle between body parts • Flexion: decreasing angle between body parts – Dorsiflexion vs. Plantarflexion – Inversion vs. Eversion • Abduction: moving away from the median plane • Adduction: moving towards the median plane • Rotation: moving around the long axis • Circumduction: moving around in circles
  5. 5. • Elevation: lifting body part superiorly • Depression: moving body part inferiorly • Supination: rotating forearm laterally • Pronation: rotating forearm medially • Protraction: Anterior movement • Retraction: Posterior movement Movements of Muscles
  6. 6. Types of Muscles
  7. 7. Skeletal Muscle Tissue • Cells – Cylindrical, long, Striations • Attached to the Skeleton • Voluntary movements • Attached to bones, fascia, skin • Origin & Insertion • Somatic nerve supply
  8. 8. Cardiac Muscle •Myocardium-heart muscle – Pumps blood through vessels • Cells – Branching, chains of cells – Single or Binucleated – Striations •Cardiac Muscle- Involuntary •Supplied by Autonomic nervous system
  9. 9. Smooth Muscle Tissue Cells Single cells, uninucleate No striations Smooth Muscle-Involuntary 2 layers-opposite orientation (peristalsis) Lines hollow organs, blood vessels Supplied by Autonomic nervous system
  10. 10. Skeletal muscles
  11. 11. •A skeletal muscle has two or more attachments. The attachment that moves the least is referred to as the origin, and the one that moves the most, the insertion •The fleshy part of the muscle is referred to as its belly. •The ends of a muscle are inserted into bones, cartilage, or ligaments by cords of fibrous tissue called tendons. Skeletal Muscle
  12. 12. Muscles of the Upper Limb
  13. 13. Deltoid
  14. 14. The biceps is tri-articulate, meaning that it works across three joints. The most important of these functions are to supinatethe forearm and flex the elbow.
  15. 15. Posterior Compartment of the Arm Triceps
  16. 16. Muscles of the Lower Limb
  17. 17. Anterior Compartment Thigh Quadriceps muscles
  18. 18. Posterior Compartment of the thigh
  19. 19. Functional Muscle Groups (Muscle Actions)
  20. 20. • Agonist: one muscle or group of muscles actively contract to produces particular movement of a joint and is/are called a primary mover (eg) biceps brachii is main flexor of forearm • Antagonist: Any muscle that opposes the action of the prime mover is an antagonist. Before a prime mover can contract, the antagonist muscle must be equally relaxed. (eg) triceps brachii is antagonist to biceps brachii Functional Muscle Groups (Skeletal Muscle action)
  21. 21. The biceps is tri-articulate, meaning that it works across three joints. The most important of these functions are to supinatethe forearm and flex the elbow.
  22. 22. Example 2 for Agonist and AntagonistExample 2 for Agonist and Antagonist
  23. 23. Fixators: A fixator contracts isometrically (i.e., contraction increases the tone but does not in itself produce movement) to stabilize the origin of the prime mover so that it can act efficiently. For example, the muscles attaching the shoulder girdle to the trunk contract as fixators to allow the deltoid to act on the shoulder joint. Functional Muscle Groups (Skeletal Muscle Action)
  24. 24. • Synergists: : In many locations in the body the prime mover muscle crosses several joints before it reaches the joint at which its main action takes place. To prevent unwanted movements in an intermediate joint, groups of muscles called synergists contract and stabilize the intermediate joints. For example, the flexor and extensor muscles of the carpus contract to fix the wrist joint, and this allows the long flexor and extensor muscles of the fingers to work efficiently Functional Muscle Groups (Skeletal Muscle Action)
  25. 25. Functional Muscle Groups • Agonist = primary mover of a muscle, major response produces particular movement – (eg) biceps brachii is main flexor of forearm • Antagonists = oppose/reverse particular movement, prevent overshooting agonistic motion – (eg) triceps brachii is antagonist to biceps brachii
  26. 26. Functional Muscle Groups • Synergists = muscles work together, adds extra force to agonistic movement, reduce undesirable extra movement – (eg) muscles crossing 2 joints • Fixators = a synergist that holds bone in place to provide stable base for movement – (eg) joint stablilizers
  27. 27. Naming Muscles • Location: (eg) brachialis = arm • Shape: (eg) deltoid = triangle • Relative Size: (eg) minimus, maximus, longus • Direction of Fascicles: (eg) oblique, rectus • Location of Attachment: (eg) brachioradialis • Number of Origins: (eg) biceps, quadriceps • Action: (eg) flexor, adductor, extensor
  28. 28. Muscle System: uses levers to move objects • How it works: A rigid bar moves on fixed point when a force is applied to it, to move object • Lever = rigid bar = bone • Fulcrum = fixed point = joint • Effort = force applied = muscle contraction • Load = object being moved = bone
  29. 29. Muscle Basics to Remember • 3 Types: Skeletal, Cardiac, Smooth • Origin vs. Insertion • Direct vs. Indirect Attachments – direct = right onto bone – indirect = via tendon/aponeurosis • more common • leave bony markings = tubercle, crest, ridge, etc. • Sometimes attach to skin
  30. 30. Thanks