HLTAAP002 Session 5: The Muscle System Notes on the Muscle System

Terminology: The word root My (o) refers to muscle. Myology is the study of muscles, conducted by a Myologist.
Movement: Muscle tissue contracts to produce movement. This includes Gross movement (e.g., walking, running) and Fine movement (e.g., writing, speaking, facial expressions).
Stability and Posture: Tendons and core muscles (abdomen, back, pelvis) stabilize joints and the body. Skeletal muscles maintain posture; weakness or stiffness leads to misalignment and pain.
Organ Support: Muscles facilitate the heartbeat, blood flow through vessels, peristalsis in the digestive system, eye movement, and uterine contractions during childbirth.
Thermoregulation: Chemical changes during muscle contraction produce heat necessary to maintain a normal body temperature.
Protection: Torso muscles and bones protect internal organs and absorb shock to reduce joint friction.

Tendons: Extremely strong connective tissue that attaches muscle to bone.
Ligaments: Fibrous bands that hold bones together at joints. They form a capsular sac containing the synovial membrane and bursa (fluid-filled sacs that reduce friction).
Fascia: Sheets of fibrous connective tissue, primarily collagen, that stabilize and separate muscles.

Naming Conventions: Muscles are named based on size, shape, fiber direction, location, number of origins, origin/insertion, or muscle action.
Attachment Points:
- Origin: Attachment to the more stationary bone.
- Insertion: Attachment to the more movable bone.
- Prime mover: The chief muscle responsible for a movement.
- Synergist: Muscles that assist the prime mover.
- Antagonist: Muscles that oppose a movement to return a limb to its original position.
Respiration: The diaphragm is a dome-shaped muscle separating the thoracic and abdominal cavities and is the chief muscle of inhalation. It works with intercostal muscles to facilitate ventilation.

Somatic Motor Neuron: Skeletal muscle requires stimulation from a nerve emerging from the spinal cord to contract.
Neuromuscular Junction (NMJ): The space between the motor neuron and the muscle. ACh (acetylcholine) is the neurotransmitter that stimulates the muscle membrane.
Movement Types:
- Flexion/Extension: Bending vs. increasing the angle of a joint.
- Abduction/Adduction: Moving away from vs. toward the midline.
- Pronation/Supination: Downward vs. upward movement.
- Inversion/Eversion: Tilting toward vs. away from the midline.
- Circumduction: Distal end of a limb moving in a circle.
- Rotation: Turning a limb around its long axis.

Muscle Tone: Continuous, passive-partial contraction that assists in upholding posture and controlling movement speed.
Cerebral Palsy: Impaired coordination or spastic paralysis caused by brain damage before or at birth.
Cramps: Uncontrollable, painful spasms often caused by mineral/electrolyte imbalance, fatigue, or prostaglandins during menstruation.
Myalgia: Muscle pain resulting from stress, injury, illness, or medications (e.g., cocaine, glucocorticoids).
Fibromyalgia: A disorder characterized by widespread musculoskeletal pain, fatigue, and cognitive issues; it affects females more than males.
Atrophy vs. Hypertrophy: Atrophy is the wasting away of muscle due to lack of use or aging. Hypertrophy is the increase in muscle fibers when protein synthesis exceeds breakdown.
Tendonitis: Inflammation of a tendon typically due to overuse.

Professionals involved in muscle health include: GP, Orthopedists, Orthopedic surgeons, Occupational therapist, Physiotherapist, Podiatrist, and Dietician.

The session concluded with an invitation for students to ask questions regarding the muscular system and related health variations.