Year 10 SEHS - Term 3 Exam Review Vocabulary

Vocabulary definitions derived directly from Year 10 SEHS Term 3 notes covering nervous system structures, muscular contraction, fibre types, energy systems, fatigue, and recovery.

Central Nervous System (CNS)

The command centre of the nervous system consisting of the brain and spinal cord, which takes in information and gives instructions.

Peripheral Nervous System (PNS)

The nerves outside the brain and spinal cord that form communication lines between the CNS and the rest of the body.

Sensory (Afferent) Neurons

Neurons that carry impulses from sensory receptors toward the CNS to gather information about internal and external stimuli.

Motor (Efferent) Neurons

Neurons that carry impulses away from the CNS to muscles and glands to produce a response such as muscular contraction.

Interneurons

Relay or association neurons found in CNS pathways that connect sensory neurons with motor neurons.

Cell Body

The part of a neuron that contains the nucleus and serves as its metabolic centre.

Dendrites

Neuron structures that conduct electrical impulses toward the cell body.

Axon

Neuron structure that conducts electrical impulses away from the cell body.

Myelin Sheath

An insulating covering around an axon formed by Schwann cells in the PNS.

Nodes of Ranvier

Gaps in the myelin sheath along the axon of a neuron.

Axon Terminals

Structures at the end of an axon that contain vesicles filled with neurotransmitters.

Synaptic Cleft

The tiny gap between adjacent neurons across which neurotransmitters diffuse.

Neuromuscular Junction

The junction between a motor neuron's axon and the muscle fibres it stimulates, also called the motor end plate.

Acetylcholine (ACh)

A neurotransmitter released at the motor end plate that causes depolarisation of the muscle membrane.

Occipital Lobe

The brain lobe responsible for visual processing and tracking.

Parietal Lobe

The brain lobe responsible for spatial awareness and sensory integration.

Frontal Lobe

The brain lobe responsible for planning, decision-making, and movement initiation.

Temporal Lobe

The brain lobe responsible for auditory processing and memory.

Epimysium

Connective tissue layer surrounding the whole skeletal muscle.

Perimysium

Connective tissue layer surrounding muscle fascicles or muscle bundles.

Endomysium

Connective tissue layer surrounding individual muscle fibres.

Sarcomere

The basic functional contractile unit of a myofibril.

Actin

Thin myofilament that contains active binding sites for myosin heads.

Myosin

Thick myofilament with heads that bind to actin to form cross-bridges.

Troponin

A protein on the thin filament that binds calcium ions and changes shape to move tropomyosin.

Tropomyosin

A protein that blocks actin's binding sites when relaxed and moves away when calcium binds to troponin.

Motor Unit

A single motor neuron plus all the specific muscle fibres it stimulates.

Type I Muscle Fibres

Slow-twitch, highly fatigue-resistant muscle fibres with high myoglobin and mitochondria count, suited to endurance and low-level contractions.

Type IIa Muscle Fibres

Fast oxidative intermediate muscle fibres that produce fast, strong contractions and can be repeated with intermediate fatigue resistance.

Type IIb Muscle Fibres

Fast glycolytic muscle fibres that produce maximum explosive power but fatigue rapidly due to low mitochondria and low myoglobin.

ATP (Adenosine Triphosphate)

The immediate energy compound used by muscle cells to fuel sliding filament contraction and cross-bridge cycling.

ATP-PC System

An anaerobic energy system that is dominant for short, maximum-intensity efforts lasting up to about $10\,s$ (trainable to about $20\,s$).

Anaerobic Glycolysis System

An anaerobic energy system dominant for high-intensity efforts lasting roughly $30\,s$ to $2\text{--}3\,min$ without relying on oxygen.

Aerobic System

An energy system requiring oxygen to produce ATP, dominant from about $2\text{--}3\,min$ to prolonged exercise durations.

Oxygen Deficit

The difference between the oxygen required for a work rate and the oxygen actually consumed at the start of exercise.

Steady State

A condition during moderate, consistent-intensity exercise where the aerobic system fully meets the body's oxygen and ATP requirements, often around $50\text{--}70\%$ MHR.

EPOC

Excess Post-Exercise Oxygen Consumption (oxygen debt); the elevated oxygen consumed after exercise to restore the body to resting conditions.

Nervous-System Fatigue

A form of fatigue where the nervous system cannot create impulses sufficiently or quickly enough to sustain calcium release and muscle stimulation.

Energy-System Fatigue

Muscular fatigue resulting from an inability to continue providing ATP at the rate required to maintain work output.

Active Recovery

Low-intensity post-exercise activity that keeps blood moving, assists with the removal of $H^+$ ions, and speeds up the EPOC process.