Muscle Health, Fatigue, and Disease Flashcards

Flashcards based on lecture notes covering muscle physiology, exercise effects, and muscle diseases.

Muscle Fatigue

Loss of force and function in muscles, often due to substrate depletion, muscle fiber damage, or build-up of metabolic by-products during exercise.

Delayed Onset Muscle Soreness (DOMS)

Muscle soreness experienced 12-72 hours post-exercise, caused by muscle fiber damage and oedema.

Fast Glycolytic (FG) Fibers

Muscle fibers that are better suited for intense activities like weight lifting and sprinting.

Slow Oxidative (SO) Fibers

Muscle fibers that are better suited for endurance activities like long-distance running.

Aerobic Exercise Effects on Muscle Fibers

Transforms some Fast Glycolytic (FG) fibers into Fast Oxidative Glycolytic (FOG) fibers, increasing oxidative enzyme levels and mitochondrial volume.

Mitochondrial Changes Due to Exercise

Mitochondria become larger and more numerous, with enzymatic changes in both glycolytic and oxidative enzymes.

Fat Metabolism with Exercise

Increased oxidation of fat at rest and during submaximal exercise due to greater muscular blood flow and increased enzyme concentrations/mitochondrial function.

Carbohydrate Metabolism with Exercise

Increased oxidation of carbohydrates during maximal exercise due to increased mitochondrial capacity and enhanced glycogen storage.

Capillarisation

Increased capillarisation leads to improved nutrient movement in muscles.

Muscular Hypertrophy

Muscle growth after birth, involving enlargement of existing fibers due to increased production of myofibrils, mitochondria, sarcoplasmic reticulum, and other organelles.

Muscular Atrophy

Wasting away of muscles, which can be disuse atrophy (reversible) or denervation atrophy (due to cut or disrupted nerve supply).

Pros of Hypertrophy

Greater cross-sectional area leads to an increased number of thick and thin filaments, resulting in more cross-bridges and greater muscle strength.

Cons of Hypertrophy

Greater diffusion distance for nutrients entering the cell and metabolic by-products leaving the cell.

Tetanus (Lockjaw)

Muscle spasm caused by the bacterium Clostridium tetani, which inhibits neurotransmitter release from inhibitory interneurons, leading to excessive excitation and muscle spasm.

Muscular Dystrophies

A group of skeletal muscle diseases (myopathies) characterized by degeneration of muscle and its replacement by connective tissue.

Duchenne Muscular Dystrophy (DMD)

X-linked recessive disease affecting males, caused by mutations in dystrophin, a protein linking actin filaments to the extracellular matrix.

Distal Arthrogryposis

Skeletal muscle disease characterized by contractures of the distal regions of the hands or feet.

Contracture

Immobility resulting from stiffness or constriction in connective tissues.