Ppt mscler system


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Ppt mscler system

  1. 1. MUSCULAR SYSTEM • Presented To : SIR SHEERAZ • Presented By: ABBAS KHAN
  2. 2. What are Muscles..  Specialized tissue that enable the body and its parts to move.
  3. 3. Muscle Derivation :  Latin word mus means mouse  its due to many of them resembles mouse with tendon representing tail tendon belly
  4. 4. Continue… • A contractile tissue which bring about movements • Muscle can be regarded as motors of body
  5. 5. Properties of Muscle • Excitability: capacity of muscle to respond to a stimulus • Contractility: ability of a muscle to shorten and generate pulling force • Extensibility: muscle can be stretched back to its original length • Elasticity: ability of muscle to recoil to original resting length after stretched
  6. 6. Muscle Classification Functionally Voluntarily can be moved at will skeletal muscle Involuntarily can’t be moved at will cardiac ,smooth muscle Heart wall,Visceral organs
  7. 7. Structurally Striated have cross striation on muscle fiber cardiac, skeletal muscle Non striated have no striation smooth muscle
  8. 8. Types of Muscle  Skeletal Muscle  Cardiac Muscle  Smooth Muscle 11/3/2013 9
  9. 9. Skeletal Muscle Human body contains over 640 skeletal muscles 40- 50% of total body weight  Muscle that can be felt and seen  Attached to bone Comes in pairs. The contraction is voluntary.  Striated – have visible banding  Cells are multinucleated Responsible for Body movement (Locomotion)
  10. 10. Functions of muscle  Body movement (Locomotion)  Maintenance of posture  Respiration  Diaphragm and intercostals contractions  Communication (Verbal and Facial)  Constriction of organs and vessels  Peristalsis of intestinal tract  Vasoconstriction of b.v. and other structures (pupils)  Production of body heat (Thermo genesis) 11/3/2013 Jipmer Physiologist 12
  11. 11. 11/3/2013 Jipmer Physiologist 13
  12. 12. Muscle ATTACHMENT  Axial musculature  Muscles with origins on the axial skeleton that position and move head, spine, rib cage  Appendicular musculature Muscles that stabilize or move appendicular components Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
  13. 13. Muscle ATTACHMENT Direct attachments Fleshy part direct attached e.g. intercostals muscle  Indirect attachments tendon or aponeurosis meet bones Tubercles, trochanters, and crests
  14. 14. Movement of Muscles  Origin: attachment that remains stationary or least mobile origin belly  Insertion: attachment of the muscle to the bone that more mobile  Belly: the fleshy part of the muscle between the tendons insertion
  15. 15. Types of muscle fibers SLOW FIBERS Type I Half the diameter of fast fibers Take three times as RESISTANT TO FATIGUE  Abundant mitochondria  Large capillary supply High concentrations of myoglobin 11/3/2013 FAST FIBERS Type IIa Large in diameter Large glycogen reserves few mitochondria Produce rapid, powerful contractions of short duration 17
  16. 16. Intermediate type IIb Similar to fast fibers Greater resistance to fatigue Activity of type I  e.g. neck, trunk muscle maintain posture 11/3/2013 type II leg muscle walking,running Jipmer Physiologist Type IIb Shoulder flexer,abbducter wieght lifting gymnastic Act 18
  17. 17. Fascicular architecture of muscle  Parallel  strap-like Sartorius  Fusiform  spindle shaped bicep brachii  Convergent  ex: pectoralis major  Pennate  "feather shaped”  Unipennate  ex: extensor digitorum longus  Bipennate  ex: rectus femoris  Circular  sphincters  ex: orbicularis oris  Multipennate  ex: deltoid
  18. 18. 11/3/2013 Jipmer Physiologist 20
  19. 19. Naming Skeletal Muscles  Location of the muscle  Shape of the muscle  Relative Size of the muscle  Direction/Orientation of the muscle fibers/cells  Number of Origins  Action of the muscle
  20. 20. Muscles Named by Location  Epicranius (around cranium)  Tibialis anterior (front of tibia) tibialis anterior
  21. 21. Name by shape  Shape:  deltoid (triangle)  serratus (saw-toothed) Deltoid  rhomboideus (rhomboid, 4 parallel sides)  orbicularis and sphincters (circular) Rhomboideus major Serratus anterior
  22. 22. Muscles Named by Size  maximus (largest) Psoas  minimis (smallest) minor  longus (longest)  brevis (short) Psoas  major (large) major  minor (small)
  23. 23. Muscles Named by Direction of Fibers  Rectus (straight) –parallel to long axis Rectus abdominis  Transverse  Oblique External oblique
  24. 24. Named for Number of Origins  Biceps (2)  Triceps (3)  Quadriceps Biceps brachii (4) Named for Action •Abductor magnus – abducts thigh Adductor magnus
  25. 25. Coordinated action of muscle  Primary Action Categories agonist  Prime mover (agonist)  Main muscle in an action  Synergist  Helper muscle in an action  Antagonist  Opposed muscle to an action  Fixater muscle wich stablize proxmal joint in movement of distal joint Fixater Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Antagonist
  26. 26. Connective Tissue of a Muscle  Epimysium. Dense c.t. surrounding entire muscle Separates muscle from surrounding tissue and  Connected to the deep fascia  Perimysium. Collagen and elastic fibers surrounding a group of muscle fibers called a fascicle  Contains b.v and nerves  Endomysium. Loose connective tissue that surrounds individual muscle fibers  Also contains b.v., nerves, and satellite cells (embryonic stem cells function in repair of muscle tissue  Collagen fibers of all 3 layers come together at each end of muscle to form a tendon or aponeurosis. 
  27. 27. Anatomy of Skeletal Muscles  The Organization of a Skeletal Muscle Figure 7-1
  28. 28. Micro anatomy of Skeletal Muscles  Microanatomy of a Muscle Fiber  Sarcolemma  Muscle cell membrane  Sarcoplasm  Muscle cell cytoplasm  Sarcoplasmic reticulum (SR)  Like smooth ER  Transverse tubules (T tubules)  Myofibrils (contraction organelle)  Sarcomeres Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
  29. 29. MicroAnatomy of Skeletal Muscles  Sarcomere—Repeating structural unit of the myofibril  Components of a sarcomere   Myofilaments  Thin filaments (mostly actin)  Thick filaments (mostly myosin) Z lines at each end  Anchor for thin filaments Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
  30. 30. Anatomy of Skeletal Muscles The Organization of a Single Muscle Fiber Figure 7-2(a)
  31. 31. Anatomy of Skeletal Muscles  The Organization of a  Single Muscle Fiber Figure 7-2(b)
  32. 32. Nerve and Blood Vessel Supply Motor supply(60%)  Alpha efferent fibers to extra fusel m.fibers  gamma efferent supply intra fusal m.fiber Sensory supply (40%)  Mylinated fiber supply m.spindle for proprioception and g.t.o Capillary beds surround muscle fibers  Muscles require large amounts of energy  Extensive vascular network delivers necessary oxygen and nutrients and  carries away metabolic waste produced by muscle fibers
  33. 33. Sensory supply Muscle Spindle + + + Alpha Motor Neuron Motor supply
  34. 34. Neuromuscular Junction  Site where an axon and muscle fiber meet Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.  Parts to know: • Motor neuron Synaptic vesicles Mitochondria • Motor end plate • Synapse Motor neuron axon Synaptic cleft Folded sarcolemma • Synaptic cleft • Synaptic vesicles Acetylcholine Axon branches Muscle fiber nucleus Motor end plate Myofibril of muscle fiber • Neurotransmitters 9 (a) 36
  35. 35. Control of Muscle Contraction  Steps in Neuromuscular Transmission  Motor neuron action potential  Acetylcholine release and binding  Action potential in sarcolemma  T tubule action potential  Calcium release from SR  Ca2+ causes myosin binding sites changes on actin.  Myosin cross bridges can now attach and the cross bridge cycle can take place. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
  36. 36.  Summary of Contraction Process Table 7-1
  37. 37. Cross bridging Process   Actin active sites and myosin cross-bridges interact Thin filaments slide past thick filaments  Cross-bridges undergo a cycle of movement  Attach, pivot, detach, return Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
  38. 38. Calcium ATP Myosin head Actin 11/3/2013 Jipmer Physiologist 40
  39. 39. Sarcomere 11/3/2013 Dark band Jipmer Physiologist 41
  40. 40. Motor Units A motor neuron and all the muscle fiber it controls  Small motor units = finer control  Motor units are intermixed in the muscle to pull evenly on the tendon  Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
  41. 41. small motor units  precise control (e.g. eye muscles large motor units gross  Motor Units control (e.g. leg muscles) Figure 7-8
  42. 42. Types of Contractions • Isotonic – muscle contracts and changes length • Isometric – muscle contracts but does not change length • Concentric – shortening contraction • Eccentric – lengthening contraction (a) Muscle contracts with Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. force greater than resistance and Most likely to cause shortens (concentric contraction) muscle injury (c) Muscle contracts but does not change length (isometric contraction) No movement Movement Movement 29 44
  43. 43. Smooth muscles Muscle Mechanics • Smooth muscles help us• to move food Muscle tone • Tension digestive through our in a “resting” muscle produced by a low level of spontaneous tract.(peristalsis)resting motor neuron activity. • Distinct from tension •Nonstriated cells passive stretching • produced by (no sarcomeres)of muscle tone • Function  Stabilizes Involuntarybones, joints  Prevents atrophy are • Smooth muscles(muscle wasting ) found in the digestive system Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
  44. 44. Types of Smooth Muscle Single unit Smooth Muscle •Fibers held together by gap junctions •Independent of n.s •Stimulated by stretch • Exhibit rhythmicity •Walls of most hollow organs •stomach,intestine,uterus 11/3/2013 Jipmer Physiologist Multi-unit Smooth Muscle • Less organized • Function as separate units • dependent on n.s • Iris of eye • Walls of blood vessels 46
  45. 45. Cardiac Muscle  Cardiac Muscle Tissue  Small cells  Single nucleus/cell  Intercalated discs  Self-exciting and rhythmicy due to c.system  No tetanic contraction
  48. 48. Muscle Strain    A muscle strain, or pulled muscle, is when your muscle is overstretched or torn. can happen in any muscle, but most common back, neck, shoulder, and hamstring . It due to high pressure on muscles during normal daily activities, with sudden heavy lifting, during sports, or while performing work tasks.
  49. 49. Muscle Hypertrophy  Enlargement of a muscle  More capillaries  More mitochondria  Caused by  Strenuous exercise  Steroid hormones
  50. 50. Muscle Atrophy  Weakening and shrinking of a muscle  May be caused  Immobilization  Loss of neural stimulation
  52. 52. What is fatigue? “loss in the capacity for developing force and / or velocity of a muscle, resulting from muscular activity under load and which is reversible by rest”
  53. 53. Age-Related Reductions  By age of 80 Muscle size, half of muscle mass has atrophied  Muscle elasticity  Muscle strength  Exercise tolerance  Injury recovery ability Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
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  55. 55. For your knowledge • • • • – – – – – – – – How many muscles are there in the human body? Answer: 640 Muscles The muscles make up about 40 % of the body mass. What is the longest muscle in the body? Answer: The Sartorius The Sartorius runs from the outside of the hip, down and across to the inside of the knee. It twists and pulls the thigh outwards. What is the smallest muscle in the body? Answer: The Stapedius The Stapedius is located deep in the ear. It is only 5mm long and thinner than cotton thread. It is involved in hearing. What is the biggest muscle in the body? Answer: The Gluteus Maximus The Gluteus Maximus is located in the buttock. It pulls the leg backwards powerfully for walking and running.
  56. 56. There are about 60 muscles in the face. Smiling is easier than frowning. It takes 20 muscles to smile and over 40 to frown. Smile and make someone happy.
  57. 57. 11/3/2013 Jipmer Physiologist 59