1.MUSCULAR SYSTEM Presented To :SIR SHEERAZ Presented By:ABBAS KHAN

2. What are Muscles.. Specialized tissue that enable the body and its parts to move. 3. Muscle Derivation : Latin word mus means mouse its due to many of them resembles mouse with tendon representing tailtendonbelly 4. Continue A contractile tissue which bring about movements Muscle can be regarded as motors of body 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. Muscle Classification Functionally Voluntarily can be moved at will skeletal muscle Involuntarily cant be moved at will cardiac ,smooth muscle Heart wall,Visceral organs 7. Structurally Striated have cross striation on muscle fiber cardiac, skeletal muscle Non striated have no striation smooth muscle 8. Types of Muscle Skeletal Muscle Cardiac Muscle Smooth Muscle 11/3/20139 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 multinucleatedResponsible for Body movement (Locomotion) 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) 11/3/2013Jipmer Physiologist12 11. 11/3/2013Jipmer Physiologist13 12. Muscle ATTACHMENT Axial musculature Muscles with origins on theaxial skeleton that position and move head, spine, rib cage Appendicular musculature Muscles that stabilize or move appendicular componentsCopyright 2007 Pearson Education, Inc., publishing as Benjamin Cummings 13. Muscle ATTACHMENT Direct attachmentsFleshy part direct attached e.g. intercostals muscle Indirect attachmentstendon or aponeurosis meet bones Tubercles, trochanters, and crests 14. Movement of Muscles Origin: attachment that remains stationary or least mobileorigin belly Insertion: attachment of the muscle to the bone that more mobile Belly: the fleshy part of the muscle between the tendonsinsertion 15. Types of muscle fibers SLOW FIBERS Type I Half the diameter of fast fibers Take three times as RESISTANT TO FATIGUE Abundantmitochondria Large capillary supply High concentrations of myoglobin 11/3/2013FAST FIBERS Type IIa Large in diameter Large glycogen reserves few mitochondria Produce rapid, powerful contractions of short duration17 16. Intermediate type IIb Similar to fast fibers Greater resistance to fatigueActivity of type I e.g. neck, trunk muscle maintain posture 11/3/2013type II leg muscle walking,runningJipmer PhysiologistType IIb Shoulder flexer,abbducter wieght lifting gymnastic Act 18 17. Fascicular architecture of muscle Parallel strap-likeSartorius Fusiform spindle shapedbicep brachii Convergent ex: pectoralis major Pennate "feather shaped Unipennate ex: extensor digitorumlongus Bipennate ex: rectus femoris Circular sphincters ex: orbicularis oris Multipennate ex: deltoid 18. 11/3/2013Jipmer Physiologist20 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. Muscles Named by Location Epicranius(around cranium) Tibialis anterior (front of tibia)tibialis anterior 21. Name by shape Shape: deltoid (triangle) serratus (saw-toothed)Deltoid rhomboideus(rhomboid, 4 parallel sides) orbicularis andsphincters (circular)Rhomboideus major Serratus anterior 22. Muscles Named by Size maximus (largest)Psoas minimis (smallest) minor longus (longest) brevis (short) Psoas major (large) major minor (small) 23. Muscles Named by Direction of Fibers Rectus (straight)parallel to long axisRectus abdominis Transverse ObliqueExternal oblique 24. Named for Number of Origins Biceps (2) Triceps (3) QuadricepsBiceps brachii(4)Named for Action Abductor magnus abducts thighAdductor magnus 25. Coordinated action of muscle Primary Action Categoriesagonist 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 CummingsAntagonist 26. Connective Tissue of a Muscle Epimysium. Dense c.t. surrounding entire muscleSeparates 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. Anatomy of Skeletal Muscles The Organization of a Skeletal MuscleFigure 7-1 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) SarcomeresCopyright 2007 Pearson Education, Inc., publishing as Benjamin Cummings 29. MicroAnatomy of Skeletal Muscles SarcomereRepeating structural unit of themyofibril Components of a sarcomere Myofilaments Thin filaments (mostly actin) Thick filaments (mostly myosin) Z lines at each end Anchor for thin filamentsCopyright 2007 Pearson Education, Inc., publishing as Benjamin Cummings 30. Anatomy of Skeletal Muscles The Organization of a Single Muscle FiberFigure 7-2(a) 31. Anatomy of Skeletal Muscles The Organization of a Single Muscle FiberFigure 7-2(b) 32. Nerve and Blood Vessel Supply Motor supply(60%) Alpha efferent fibers to extra fusel m.fibers gamma efferent supply intra fusal m.fiberSensory supply (40%) Mylinated fiber supply m.spindle for proprioceptionand g.t.oCapillary beds surround muscle fibers Muscles require large amounts of energy Extensive vascular network delivers necessaryoxygen and nutrients and carries away metabolic waste produced by muscle fibers 33. Sensory supply Muscle Spindle+++Alpha Motor NeuronMotor supply 34. Neuromuscular Junction Site where an axon and muscle fiber meetCopyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Parts to know: Motor neuronSynaptic vesicles Mitochondria Motor end plate SynapseMotor neuron axonSynaptic cleftFolded sarcolemma Synaptic cleft Synaptic vesiclesAcetylcholineAxon branches Muscle fiber nucleusMotor end plate Myofibril of muscle fiber Neurotransmitters 9 (a)36 35. Control of Muscle Contraction Steps in Neuromuscular Transmission Motor neuron action potential Acetylcholine release and binding Action potential in sarcolemmaT tubule action potentialCalcium release from SRCa2+ 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. Summary of Contraction ProcessTable 7-1 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, returnCopyright 2007 Pearson Education, Inc., publishing as Benjamin Cummings 38. Calcium ATPMyosin headActin 11/3/2013Jipmer Physiologist40 39. Sarcomere11/3/2013Dark bandJipmer Physiologist41 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. small motor units precise control (e.g. eye muscles large motor units gross Motor Units control (e.g. leg muscles)Figure 7-8 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) Musclecontracts 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 MovementMovement29 44 43. Smooth musclesMuscle 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. 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,uterus11/3/2013Jipmer PhysiologistMulti-unit Smooth Muscle Less organized Function as separate units dependent on n.s Iris of eye Walls of blood vessels46 45. Cardiac Muscle Cardiac Muscle Tissue Small cells Single nucleus/cell Intercalated discs Self-exciting andrhythmicy due to c.system No tetanic contraction 46. Fibrillation ABNORMAL CONTRACTION OF CARDIADC MUSCLE CARDIAC CHAMBER DON,T CONRACT COMPLETELY RESULT IN DISRUPTION OF PUMPING ACTION INAFFECTIVE PUMPING AND ABNORMAL CONTRACTION OF ATRIA AND VENTRICLEsTWO TYPES 1.ATRIAL FIBRILLATION 2.VENTRICULER FIBRILLATION 47. VENTRICLE FIVRILLATION 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. Muscle Hypertrophy Enlargement of a muscle More capillaries More mitochondria Caused by Strenuous exercise Steroid hormones 50. Muscle Atrophy Weakening and shrinking of amuscle May be caused Immobilization Loss of neural stimulation 51. PARALYSIS LOSS OF MOTER POWER ISCALLED PARALYSIS CAUSED BY DAMAGE TO MOTER NEURAL PATHWAYS OR it could be INHERIT DESEASE OF MUSCLE 52. What is fatigue? loss in the capacity fordeveloping force and / or velocity of a muscle, resulting from muscular activity under load and which is reversible by rest 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 54. 56 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. 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. 11/3/2013Jipmer Physiologist59