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Muscular System

Explore the key functions, types, and characteristics of the muscular system, including skeletal, cardiac, and smooth muscles. Learn about muscle contraction, heat production, and body movements. Discover how muscles function and the importance of ATP as an energy source.

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Muscular System

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  1. Muscular System Mrs. Yanac Anatomy & Physiology

  2. Big Ideas • Muscle makes us over ½ of the body’s mass • Consists of over 600 muscles • Consumes a large amount of energy obtained through diet • Muscles can ONLY contract & shorten in length • Categorized into 3 categories • Skeletal, Cardiac, Smooth

  3. Muscle Types • All body movements are determined by three types of muscles • Smooth (Involuntary) • cannot be controlled by will • Cardiac (Involuntary) • control the contractions of the heart • Skeletal (Voluntary) • can be controlled by will

  4. Functions of Skeletal Muscle • Provides voluntary movement of body • Enables breathing, blinking, and smiling • Allows you to hop, skip, jump, or do push-ups • Maintains posture • Produces heat

  5. Function of Smooth Muscle • Called smooth muscle because they are unmarked by striations, small spindle shaped • Unattached to bones, act slowly, do not tire easily and can remain contracted for a long time • Not under conscious control so they are also called involuntary muscles • Found in walls of internal organs (intestines, bladder, stomach, uterus, blood vessels)

  6. Provides movement of internal organs • Moves food through digestive tract (peristalsis) • Enables bladder control • Causes involuntary actions • Reflex actions • Adjusts opening of pupils • Causes hair to stand on end

  7. Function of Cardiac Muscle • Found only in the heart • Involuntary muscle • Requires a continuous supply of oxygen to function • Cardiac muscle cells begin to die after 30 seconds of oxygen cut-off • Striated and branched • Directs circulation of blood

  8. Special muscles • Sphincter (dilator) muscles are openings between • the esophagus and stomach • the stomach and small intestines • walls of the anus, urethra and mouth • Open and close to control passage of substances

  9. Characteristics of Muscles • All muscles have 4 common characteristics • Excitability – ability to respond to a stimulus (ie: nerve impulse) • Contractibility– muscle fibers that are stimulated by nerves contract (become shorter) and causes movement • Extensibility– ability to be stretched • Elasticity– allows the muscle to return to its original shape after it has been stretched

  10. Sources of Heat/Energy • When muscles work, they produce heat that our body needs to function properly • Major source of this energy is ATP – a compound found in muscle cells • ATP requires muscle cells to have oxygen, glucose and other materials circulated by the blood • When the muscle is stimulated, ATP is released, thus producing heat

  11. Muscle Contraction • Sliding Filament Theory

  12. Attachments & Actions of Skeletal Muscles Actions depend largely on what the muscles are attached to Attachment sites Origin – an attachment site for a less movable bone Insertion– an attachment site for a more moveable bone

  13. Attachments & Actions (cont.) • Movement usually produced by a group of muscles • Prime mover– muscle responsible for most of the movement • Synergists – muscles that help the prime mover by stabilizing joints • Antagonist (agonist) – produces movement opposite to prime mover • Relaxes when prime mover contracts

  14. Attachments & Actions: Body Movements Flexion – bending a body part Extension– straightening a body part Hyperextension– extending a body part past the normal anatomical position Dorsiflexion– pointing the toes up Plantar flexion– pointing the toes down Abduction– moving a body part away from the anatomical position Adduction– moving a body part toward the anatomical position

  15. Circumduction – moving a body part in a circle Pronation – turning the palm of the hand down Supination – turning the palm of the hand up Inversion– turning the sole of the foot medially Eversion– turning the sole of the foot laterally Retraction– moving a body part posteriorly Protraction– moving a body part anteriorly Attachments & Actions: Body Movements(cont.)

  16. Attachments & Actions: Body Movements(cont.) Elevation – lifting a body part; for example, elevating the shoulders as in a shrugging expression Depression– lowering a body part; for example, lowering the shoulders

  17. Let’s watch Hank give his overview • Crash Course – Big Guns https://www.youtube.com/watch?v=jqy0i1KXUO4

  18. The muscle name indicates Location Size Action Shape OR Number of attachments of the muscle As you study muscles, you will find it easier to remember them if you think about what the name describes. Major Skeletal Muscles

  19. Biceps – flexes lower arm Deltoid – abducts arm; injection site Sternocleidomastoid – turns head Gastrocnemius – flexes sole of feet Latissimus dorsi – extends & adducts upper arm Pectoralis major – adducts and flexes upper arm Intercostals – moves ribs for breathing MUSCLES YOU SHOULD KNOW THE FUNCTIONS OF:

  20. Trapezius – extends head, moves shoulder • Triceps – extends lower arm • Gluteus maximus – extends thigh; injection site • Sartorius – abducts thigh, flexes leg • Vastus lateralis – extends leg • Rectus abdominus – compresses the abdomen • Rectus femoris – flexes thigh & extends lower leg • Tibialis anterior – flexes and inverts foot

  21. Strains – injuries due to over-stretched muscles or tendons Sprains – more serious injuries that result in tears to tendons, ligaments, and/or cartilage of joints RICE is recommended treatment for either Rest Ice Compression Elevation Muscle Strains and Sprains

  22. Prevention Warm upmuscles A few minutes before an intense activity raises muscle temperature and makes muscle more pliable Stretching Improves muscle performance and should always be done after the warm-up or after exercising Cooling down or slowing down Before completely stopping prevents pooling of blood in the legs and helps remove lactic acid from muscles Muscle Strains and Sprains (cont.)

  23. Aging and the Musculoskeletal System • Contractions become slower and not as strong • Dexterity and gripping ability decrease • Mobility may decrease • Assistive devices helpful • Routine exercise • Swimming • Physical therapy

  24. Diseases and Disorders of the Muscular System

  25. Diseases and Disorders of the Muscular System (cont.)

  26. Problems from lack of movement • Contractures • Tightening and shortening of a muscle resulting in a permanent flexing of a joint • Muscle atrophy • Muscles become weak and joints become stiff • Circulatory impairment • Blood clots and pressure ulcers can develop • Mineral loss • Especially calcium from the bones making bones brittle and easily to be fractured • Other problems • Poor appetite; constipation; urinary infections; respiratory problems; and pneumonia

  27. Point to Ponder: Everyone has a 'risk muscle.' You keep it in shape by trying new things. If you don't, it atrophies. Make a point of using it at least once a day. ~Roger von Oech

  28. Check out this link to learn more • Interactive Body

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