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Muscular system

Muscular system. Muscle Functions. Producing movement Maintaining posture Stabilizing joints Generating Heat. Contraction of a skeletal muscle as a whole. Graded responses: different degrees of shortening. 1. changing the frequency of muscle stimulation

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Muscular system

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  1. Muscular system

  2. Muscle Functions • Producing movement • Maintaining posture • Stabilizing joints • Generating Heat

  3. Contraction of a skeletal muscle as a whole • Graded responses: different degrees of shortening. • 1. changing the frequency of muscle stimulation • 2. changing the number of muscle cells being stimulated • Muscle twitches: single brief, jerky contractions. Not normal operation • Fused or complete tetanus: contracted smoothly and sustained • Incomplete tetanus or unfused: when the muscle is trying to reach fused contraction.

  4. Muscle fatigue and oxygen debt • Muscle fatigue: when a muscle cannot contract even when being stimulated. • Happens when we exercise our muscles strenuously for a long time. • Oxygen debt: muscle fatigue happens because of oxygen debt. A person cannot take in oxygen fast enough to supply with oxygen in the muscle. • Working muscles vigorously • When there is a lack of oxygen in the muscles lactic acid starts to build up

  5. Muscle contractions • Isotonic contractions: “same tone” when muscle is in sliding movement. Smiling, bending arm, bending leg, rotating arm • Isometric contracitons: “same measurement” When muscles cannot move anymore. • When you are trying to lift or move a 400 lb dresser, when you push against the wall.

  6. Muscle tone • The state of continuous partial contraction. • Flaccid: Soft and flabby which leads to atrophy(waste away).

  7. 5 Golden Rules of Skeletal Muscle Activity • All muscles cross at least one joint. • Typically, the bulk of the muscle lies proximal to the joint crossed. • All muscles have at least two attachment points: origin and insertion. • Muscles can only pull; the never push. • During contraction, the muscle insertion moves toward the origin.

  8. Origin and insertion • Origin: immovable bone • Insertion: movable bone attachment. • When contraction occurs the insertion moves toward the origin.

  9. Movements • Flexion: decreases angle of the joint • Extension: increases the angle of the joint • Rotation: movement of a bone around its longitudinal axis. • Abduction: moving limb away from midline • Adduction: moving limb toward midline • Circumduction: proximal end of bone is stationary and the distal end is moving in a circle.

  10. Special movements • Dorsiflexion : moving the foot at the ankle up • Plantar flexion: moving the foot at the ankle down. • Inversion: turn the foot toward the middle • Eversion: turn the foot toward the outside of the leg • Supination: turning the hand to face the anterior side • Pronation: turning the hand to face the posterior side • Opposition: touching the fingers to the thumb.

  11. Types of muscles • Prime movers: major responsibility of a particular movement. • Antagonist: oppose or reverse movement. • Synergist: helps the prime mover by reducing undesirable movement. • Fixator: specialized synergist, stabilize the origin

  12. Naming skeletal muscles • Direction of the muscle fiber • Relative size of the muscle • Location of the muscle • Number of origins • Location of the muscle’s origin and insertion • Shape of the muscle • Action of the muscle

  13. Head and Neck muscles • Frontalis • Orbicularisoculi • Buccinator • Zygomaticus • Masseter • Temporalis • Playtusma • Sternocleidomastoid

  14. Trunk Muscles • Anterior muscles: • Pectoralis major • Intercostal muscles • Rectus abdominis • External oblique • Internal oblique • Transverse abdominis • Posterior muscles: • Trapezius • Latissimusdorsi • Erector spinae • Iliocostalis • Longissimus • Spinalis • deltoid

  15. Muscles of the upper limb • Upper arm • Biceps brachii • Brachialis • Triceps brachii • Lower arm • Brachioradialis • Flexor carpiradialis • Flexor carpiulnaris • Extensor carpiulnaris • Extensor digitorum

  16. Muscles of the lower limb • Upper leg • Sartorius • Adductor • Quadricep group • Rectus femoris • Vastuslateralis • Vastusmedialis • Fibularislongus • Extensor digitorum • Tibialis anterior • Hamstring group: • Biceps femoris • Semitendinosus • Semimembranosus • Gluteus maximus • Gluteus medius • Lower leg • Fibularislongus • Extensor digitorumlongus • Tibialis anterior • Gastrocnemius • Soleus • Fibularislongus

  17. Homeostatic imbalances • Muscular dystrophy: inherited muscle destroying disease. Muscle degenerates and atrophies • Myasthenia gravis: happens during adulthood. Shortage of acetylcholine receptors at the neuro-muscular junction. Auto immune disease. Will result in death because the respiratory muscles fail.

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