IB Sports, exercise and health science B.1.3.1 Muscle Tissue, Neuromuscular Activation, and Motor Unit Recruitment Key Definitions

Atrophy – A decrease in muscle mass and strength due to disuse, injury, or aging.

Hypertrophy – An increase in muscle size and strength due to resistance training and consistent use.

A motor unit consists of a single motor neuron and all the muscle fibers it innervates.

Motor Unit – A motor neuron and the muscle fibers it innervates, functioning as a single unit to produce movement.

Muscle tissue is a specialized type of tissue composed of muscle fibers that contract to generate force and facilitate movement.

The neuromuscular junction (NMJ) is the synapse (connection) between a motor neuron and a skeletal muscle fiber.

A neuron is a nerve cell that transmits electrical and chemical signals to control bodily functions, including movement.

A neurotransmitter is a chemical messenger that transmits signals between neurons and other cells.