Overview
This lecture covers the structure, types, and functions of the muscular system, common muscle disorders and injuries, and important terminology.
Muscle System Basics
- The muscular system includes over 600 muscles responsible for movement, breathing, blood pumping, and digestion.
- Muscles work with bones to allow movement and maintain posture.
- Without muscles, actions like walking, talking, or blinking would be impossible.
Types of Muscles
- Skeletal muscle: Voluntary, striated, attached to bones; responsible for movement and posture.
- Cardiac muscle: Involuntary, striated, found in the heart; pumps blood rhythmically and contains many mitochondria.
- Smooth muscle: Involuntary, non-striated, in the walls of organs and vessels; controls digestion and blood flow.
Muscle Structure and Function
- Muscle fibers bundle together to form fascicles.
- Ligaments connect bone to bone; tendons connect muscle to bone.
- The agonist (prime mover) does the primary action; the antagonist opposes it (e.g., biceps and triceps).
- Muscles are classified by their location, control, and appearance.
Chronic Muscle Disorders
- Muscular dystrophy (MD): Hereditary, progressive skeletal muscle weakness; Duchenne type most common in boys.
- Myasthenia gravis (MG): Autoimmune, causes fluctuating muscle weakness, especially face/eyes; symptoms include drooping eyelids (ptosis) and dysphagia.
- Fibromyalgia: Widespread muscle pain, stiffness, fatigue, and sleep issues.
- ALS (Amyotrophic lateral sclerosis): Progressive nerve degeneration causing muscle atrophy and weakness.
Common Muscle Injuries & Conditions
- Carpal tunnel syndrome: Median nerve compression at the wrist, causing hand/finger pain.
- Plantar fasciitis: Inflammation of foot fascia causing pain, especially with weight-bearing activities.
- Hamstring injury: Strain/tear in thigh muscles, common in athletes.
- Shin splints: Lower leg pain along tibia from overuse.
Paralysis Terminology
- Paralysis: Complete loss of voluntary movement.
- Paresis: Partial/incomplete paralysis (e.g., hemiparesis—weakness on one side).
- Hemiplegia: Total paralysis on one side of the body.
- Paraplegia: Paralysis of both legs.
- Quadriplegia: Paralysis of all four limbs.
- Monoplegia: Paralysis of one limb.
Key Terms & Definitions
- Fascia — fibrous membrane surrounding muscles.
- Kinesio — movement.
- Musculo/Myo — muscle.
- Ligamento — ligament.
- Tendo/Tendino — tendon.
- Tono — tone.
- Agonist — main muscle causing movement.
- Antagonist — opposes the main movement.
- Atrophy — muscle wasting/shrinking.
- RICE — Rest, Ice, Compression, Elevation for injury care.
- ROM — range of motion.
- ATP — energy molecule produced by mitochondria.
Action Items / Next Steps
- Review muscle types, structure, and function.
- Memorize key terms and their definitions.
- Study chronic muscle disorders and common injuries.
- Practice or review RICE first aid steps for muscle injuries.