Anatomy and Functions of the Muscular System
This article aims to provide a comprehensive overview of the muscular system, including its anatomy and major functions. The muscular system is responsible for producing movement, heat production, and maintaining posture. The
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About Anatomy and Functions of the Muscular System
PowerPoint presentation about 'Anatomy and Functions of the Muscular System'. This presentation describes the topic on This article aims to provide a comprehensive overview of the muscular system, including its anatomy and major functions. The muscular system is responsible for producing movement, heat production, and maintaining posture. The. The key topics included in this slideshow are . Download this presentation absolutely free.
Slide2Anatomy of a Muscle
Slide3Major Functions of the MuscularSystem • Produce Movement • Heat production • Maintain Posture
Slide4Skeletal Muscle-Voluntary MuscleThreadlike cells that have multiple nuclei Many cross striations (stripes) Attached to bones to produce body movement or facial expressions Smooth Muscle-Involuntary Muscle Elongated narrow cells with single nucleus No cross striation s Found in the walls of hollow organs to propel food through them by peristalsis Cardiac Muscle-Also involuntary Found only in the heart Branching cells joined by intercalated disks with gap junctions that allow ions to pass freely from cell to cell=rapid conduction of electrical impulse.
Slide6Striated MuscleMultinucleated Striations are visible Caused by the sarcomeres.
Slide7TermsSarcomere , Sarcolemma -cell membrane Sarcoplasmic Reticulum- like an endoplasmic reticulum of any cell.
Slide10Physiology of Muscles contractionWhat Happens and Why? 1. A nerve impulse reaches the end of a motor neuron – releases acetylcholine 2. Acetylcholine diffuses across the gap of the neuromuscular junction and binds to receptors on the motor endplate of the muscle fiber. 3. Impulse travels along the sarcolemma, to the T tubules to sacs of the SR.
Slide11THEN What HAPPENS?4. Ca++ is released from the SR into the sarcoplasm, where it binds to troponin mlcs in the thin myofilaments. 5. Tropomyosin mlcs in the myofilaments shift, exposing actin’s active sites. 6. Energized myosin cross bridges of the thick myofilaments bind to actin and pull the thin myofilaments together. 7. Muscles Shortens.
Slide14Sarcomere structureMyosin Actin
Slide15Sliding Filament Theory
Slide17Types of Muscle contractions• Isotonic –muscle shortens and movement occurs. • Isometric- muscle does not shorten but tension increases.
Slide18Twitch contraction• Threshold stimulus – electrical stimulus of sufficient intensity must be applied to the muscle. • A single brief threshold stimulus produces a quick jerk of the muscle. 2msec 15msec 25msec
Slide19Treppe: A Staircase phenomenon • A gradual step-like increase in the strength of contraction that can be observed in a series of twitch contractions that occur about 1 second apart. • Muscle Fatigue - Repeated stimulation of muscle in time lessens its excitability and contractility.
Slide20TetanusSmooth sustained contractions • Stimuli comes in rapid succession the muscle does not have time to relax completely before the next contraction. • Normal skeletal muscles exhibit this most of the time. Looks like one continuous contraction Rapid repeated Twitch contractions
Slide21Muscle Tone--tonic contractions A continual partial contraction. • Maintaining posture – sitting or standing • When you pass out/faint muscle tone is lost • Muscles with Less tone are flaccid. • Muscles with More tone are spastic. • Tone is maintained by a negative feedback mechanisms centered in the nervous system (in spinal cord)
Slide22Muscle Problems• Cramps -painful muscle spasms (involuntary twitches) caused by any irritation or ion and water imbalance • Convulsions -uncoordinated tetanic contractions of varying groups of muscles. May result from a disturbance in the brain or seizure. AP along motor nerve increases and becomes disorganized
Slide23•Fibrillation – abnormal contraction in which individual fibers contract out of sync.(asynchronously) instead of at the same time.
Slide24Muscular Disorders• Sprains – Joint and ligament damage • Myalgia – Muscle pain • Contusions – bruises – localized bleeding • Poliomyelitis – Viral infection of the nerves that control skeletal muscles. • Muscular Dystrophy – A group of Genetic Disease characterized by atrophy of skeletal muscle tissues. Some forms Fatal
Slide25•Myasthenia Gravis – Autoimmune disease in which the immune system attacks muscle cells at the neuromuscular junction So nerve impulses are unable to fully stimulate the affected muscle. • Hernias – Weakness of abdominal muscles can lead to protrusion of an abdominal organ. • Strangulated Hernia – Cuts off blood supply to an organ which can lead to gangrene – death of the organ or individual – Requires emergency surgery.