Overview of Muscular-System it's structure and components
- 1. The Muscular System ANATOMY AND PHYSIOLOGY OF MUSCULAR SYSTEM Dr.Ibtisam Khalaf Abd Ali
- 4. MUSCLE TISSUE • All muscle tissue is composed of muscle cell “muscle fibers”, and exhibits specific characteristics including the following: • 1. Excitability: response to stimuli by initiating electrical signal (action potential) that spread across plasma membrane and spark internal events leading to muscle contraction. • 2. Contractility: cell shortening. • 3. Extensibility: extending in length in response to contraction of opposing muscle cells. 4. Elasticity: ability to return to its original length • when tension is released
- 5. TYPES OF MUSCLE OR MUSCLE TISSUE • 1. Skeletal muscle. • 2. Cardiac muscle . • 3. Smooth muscle.
- 6. SKELETAL MUSCLE • I. Structural Organization of Skeletal Muscle • 1. Structures of muscle. • a. Epimysium b. • d. Muscle fiber e. • g. Deep fascia h. Fascicle c. Perimysium Endomysium f. Myofibrils Tendon i. Sattellite cel
- 7. Structural Organization of Skeletal Muscle
- 8. 2. Structures of fascicle. • a. Perimysium • b.Muscle fiber • c. Endomysium • d.Nerve
- 9. 3. Structures of muscle fiber (muscle cell). • a. Endomysium • b.Myofibril • c. Neuromuscular junction • d. Nuclei
- 10. The Structure of Skeletal Muscle fiber
- 11. II. Structural Organization of Myofibrils and Myofilaments • . Structures of myofibrils: compose from many sarcomeres • Sarcomere: the smallest contractile unit in myofibril of striated muscle fiber. Each sarcomere composed from: • a. Myofilament – Actin- (Thin filament) • b. Myofilament-Myosin (Thick filament) •
- 12. Arrangement of filaments in skeletal muscle fiber
- 14. CONTRACTION OF SKELETAL MUSCLE Contraction: is the sliding of actin over myosin • in the presence of Ca++ (calcium ion). “Skeletal muscle are attached to bones by tendons, and contraction of skeletal muscle exerts a pull on bone and movement”, most skeleton muscles extend between bones. The less movable point of attachment of the muscle called “Origin”, and the more movable called “Insertion”.
- 15. I. Steps Involved in the Mechanisms of Sliding Theory
- 16. I. Steps Involved in the Mechanisms of Sliding Theory: • 1. Excitable tissues: nerve and muscle (nerve impulse in axons cause muscle impulses in sarcolemma). • 2. Excitable cell: cell that is capable to create and conduct action potential • 3. Action potential: Changes in membrane potential of excitable cells .also defined as electrical activity or electrical signal. • 4. Motor end plate produces neurotransmeter at the neuromuscular junction, to stimulate the cell membrane (sarcolema) to produce Action potential (electrical signal).
- 17. • 5. Action potential (electrical signal) spread through cell membrane to “T –tube” and then to sarcoplasmic reticulum to release calcium ion. • 6. Calcium ion triggers the process of sliding. • 7. Relaxation: the period after a contraction when the tension in the muscle fiber return to resting levels, and this done by: • a. Active cytosolic calcium (Ca++) transported across the cell membrane into the extracellular fluid. b. Active cytosolic calcium (Ca++) transported into • the sarcoplasmic reticulum.
- 18. Steps in the initiation and the end of contraction
- 19. Relase and uptake of calcium by the Sarcoplasmic Reticulum during Contraction and Relaxation of Skeletal Muscle
- 21. CONTROL OF SKELETAL MUSCLE CONTRACTION Skeletal muscle fibers contract only under the • control of the nervous system. Communication between the nervous system and the skeletal muscle fiber occurs at a specialized intercellular connection known as neuromuscular junction
- 22. I. Structures of Neuromuscular Junction (Chemical Synapse and Motor End Plate) • (Structure where axons transmit nerve impulse to muscle fiber) • 1. Synaptic knob (terminal) • 2. Acetylcholine (ACh) (Synaptic Vesicles) • 3. Synaptic cleft • 4. Motor end plate • 5. Sarcolemma • 6. Acetylcholine receptor • 7. Acetylcholinestrase • (AChE)
- 24. II. Ions Fluxes in Action Potential • 1.Sodium • 2.Potassium • 3.Calcium
- 26. MUSCLE PERFORMANCE • Muscle performance: mean power and endurance. • Power: the ability to act (capability). • Endurance: the ability to sustain an activity over a period of time.
- 27. I. Factors Determine the Performance Capabilities of any Skeletal Muscle • 1. Types of muscle fibers in the muscle. • a. Fast fibers. • b. Slow fibers. • c. Intermediate fiber. • 2. Physical Conditioning • a. Aerobic endurance. • b. Anaerobic endurance.
- 28. MUSCLE TONE AND CONTRACTION I. Muscle Tone: normal tension, in muscle the resistance to passive elongation or stretch; or partial contraction of the muscle; or residual muscle tension II. Muscle Contraction: shortening of the muscle Types of Muscle Contraction 1. Isometric contraction. 2. Isotonic contraction
- 29. III. Gluteal Intramuscular Injection
- 30. ENERGETIC OF MUSCULAR ACTIVITY A single muscle fiber may contain 15 billion thick filaments, during muscle fiber contraction, each thick filament break down roughly 2500 ATP molecule per second. Small skeletal muscle contains thousands of muscle fibers.
- 31. I. Sources of Energy Stored in Muscle Fiber 1. ATP “Adenosine triphosphate” 2. CP “Creatine phosphate” 3. Glycogen ATP + Creatine Creatine Phosphokinase ADP+ Creatine phosphate ADP + Creatine phosphate Creatine Phosphokinase ATP + Creatine
- 32. II.ATP Generation 1. Aerobic metabolism “Oxidative phosphorelation”. 2. Anaerobic metabolism “glycolysis”.
- 33. III. Hormones and Muscle Metabolism 1. Growth hormone. 2. Testosterone.
- 34. The three sources of ATP production during Muscle contraction
- 35. FUNCTIONS OF SKELETAL MUSCLE 1. Producing skeletal movement. 2. Maintaining pusture and body position. 3. Supporting soft tissues. 4. Guarding enterance and exits. 5. Maintaining body temperature.
- 36. DEVELOPMENT OF SKELETAL MUSCLE
- 37. CARDIAC MUSCLE I. Cardiac Muscle Fibers are individual muscle fibers arranged in thick bundles like skeletal muscle fiber, but shorter and thicker, and have one or two nuclei. Cardiac muscle fiber forms Y- shaped branches; it is attached to adjacent muscle fibers by junctions termed intercalated discs
- 40. Specific structure of cardiac muscle fiber 1. Intercalated disc. 2. Generally centrally located single nucleus. 3. Cardiac muscle fibers are: thinner and shorter than skeletal muscle fiber. 4. Contractions of cardiac muscle fiber depend on Ca++ in ECF and sarcoplasmic reticulum. 5. CMF are slower onset in contraction and resistant to fatigue. 6. CMFs control by pacemaker cells (Automaticity). 7. CMFs depend on aerobic metabolism (fat and carbohydrate) to maintain energy.
- 41. II. Control of Cardiac Muscle Contraction 1. Automaticity. 2. Autonomic innervations. 3. Blood born chemicals .
- 42. SMOOTH MUSCLEI. Smooth Muscle Fiber Characteristic 1. Small cell. 2. Have one nucleus. 3. Capacity to divide. 4. Composed from thick and thin filaments and dense body. 5. Thick and thin filaments don’t organize into myofibrils. 6. Slow onset contraction, and may be tetanized and resistant to fatigue. 7. Primarily aerobic metabolism. 8. Depend on ECF Ca++ to maintain contraction. 9. No T-tube and dispersed sarcoplasmic reticular throughout sarcoplasm.
- 45. II. Types of Smooth Muscle 1. Single unit smooth muscle (visceral smooth muscle). Found for example in the wall of gastrointestinal tract, gallbladder, urinary bladder and other internal organs. 2. Mutiunit smooth muscle found for example in iris of the eye (to regulate the diameter of pupil), male reproductive gland and wall of large arteries. •
- 48. III. Control of Smooth Muscle Contraction
- 50. IV. Types of Synaptic Communication • 1. Chemical synapse. • 2. Electrical synapse.
- 52. DIFFERENCES BETWEEN SKELETAL MUSCLE, CARDIAC MUSCLE AND SMOOTH MUSCLE TISSUES
- 53. CLINICAL TERMINOLOGY OF MUSCULAR SYSTEM Convulsion: a series of involuntary contraction of the voluntary muscles produced hypoglycemia, hypocalcemia, metabolic disturbances, hormonal imbalances, brain cell injury, stroke, anoxia, hemorrhage, high fever and epilepsy. Cramp: painful spasmodic muscular contraction. Creatine: nonprotein substance synthesized in the body from three amino acids: arginine, glycine and methionine .present in the muscle to store high energy phosphate necessary for muscle contraction. Dystrophy : imperfect nutrition. Endurance: the ability to sustain an activity over a period of time. Fibromyalgia syndrome : An inflammatory disorder characterized by a distinctive pattern of symptoms including tender points of body surface.
- 54. Fibrosis : process in which muscle tissue is replaced by fibrous connective tissue ,making muscle weaker and less flexible. Hypertonia : abnormally increased tonicity or strength . Muscle atrophy: skeletal muscle that is not regularly stimulated by a motor neuron loses muscle tone and mass. The reduction in muscle size, tone and power is called atrophy. Muscle fatigue: muscle can no longer contract ,because of change in pH ,due to building of lactic acid, a lack of energy or other problem. Muscle Contraction: shortening of the muscle. Muscular dystrophy : degenerative myopathies that produce muscle weakness and atrophy.
- 55. Power: the ability to act (capability). Spasm: sudden involuntary contraction of muscle or group of muscle accompanied by pain Synapse: the junction between the processes of two neurons or between a neuron and effector organ (muscle, gland or GI neurons) Tendonitis: inflammation of tendons and of tendon-muscle attachments, one of the most common causes of acute pain in the shoulder. It is frequently associated with calcium deposit (calcium tendinitis) which may involve the bursa around the tendon or near the joint, causing bursitis . Tetany : continuous tonic spasm of a muscle, it is due to abnormal calcium metabolism ,vitamin D deficiency and alkalosis. Tone :normal tension, in muscle the resistance to passive elongation or stretch. Twitch : mechanical response of skeletal muscle to single volley action potential