The Muscular System Notes

Overview of the Muscular System

• Functions of the Muscular System:

  • Movement

  • Stability

  • Posture

  • Protection

  • Heat production

  • Circulation

Types of Muscles

• Three Major Types of Muscles:

  1. Skeletal Muscle:

     • Voluntary control

     • Attached to bones

     • Striated appearance

     • Fast contraction speed

  2. Smooth Muscle:

     • Involuntary control

     • Found in hollow organs & blood vessels

     • Non-striated appearance

     • Slow contraction speed

  3. Cardiac Muscle:

     • Involuntary control

     • Found in the heart

     • Striated with intercalated discs

     • Medium contraction speed

Characteristics of Muscle Tissue

• Four Main Characteristics:

  • Excitability: Ability to respond to stimuli

  • Contractility: Ability to shorten and thicken

  • Extensibility: Ability to stretch

  • Elasticity: Ability to return to original length

Muscle Functions

• Movement: Muscles contract to pull on bones, producing movement.

• Stability: Muscles stabilize joints during movement.

• Posture: Maintain correct body position.

• Protection: Muscles cover and protect internal organs.

• Heat Production: Muscle contractions generate heat.

• Circulation: Aid in moving substances through the body.

Muscle Contraction Types

• Concentric: Muscle shortens, pulling on bones; e.g., lifting a weight.

• Isometric: Muscle contracts without changing length; e.g., holding a weight still.

• Eccentric: Muscle lengthens while contracting; e.g., lowering a weight.

Agonists, Antagonists, Synergists, and Fixators

• Agonist: Provides main force for movement.

• Antagonist: Opposing muscle that relaxes during movement.

• Synergist: Stabilizes joints and assists movement.

• Fixator: Stabilizes the origin of the agonist.

Effects of Aging on Muscles

• Decrease in mass, strength, endurance, and recovery.

• Sarcopenia: Age-related muscle loss.

• Regular exercise can mitigate effects of aging on muscle mass.

Effects of Exercise on Muscles

• Hypertrophy: Increase in muscle size and strength.

• High intensity exercise builds strength; low intensity improves endurance.

Common Muscular Disorders

1. Bruise: Injury to tissue or skin.

2. Carpal Tunnel Syndrome: Nerve compression in the wrist.

3. Cramp: Sudden, involuntary muscle contraction.

4. Fibromyalgia: Chronic widespread pain.

5. Muscular Dystrophy: Genetic disease causing muscle weakness.

6. Myasthenia Gravis: Muscle weakness due to antibody production.

7. Myositis: Muscle inflammation.

8. Poliomyelitis: Viral infection affecting muscle movement.

9. Rhabdomyolysis: Breakdown of muscle tissue.

10. Strain: Stretching or tearing muscle fibers.

11. Tendonitis: Inflammation of tendon.

12. Tetanus: Bacterial infection causing muscle spasms.

Treatment Approaches for Injuries

• Rest, Ice, Compression, Elevation (RICE) for strains and bruises.

• Activity modifications for carpal tunnel syndrome and muscle tensions.