Year 9 Body Coordination Assessment Revision Checklist 2026

Homeostasis

Maintaining a stable internal environment.

Stimulus

A change in the internal or external environment.

Receptor

Detects a stimulus.

Command centre

Processes information and decides on a response.

Effector

A muscle or gland that carries out a response.

Stimulus-response model

Stimulus → receptor → command centre → effector → response.

Negative feedback

Reverses a change to return the body to a stable condition.

External stimulus

A change outside the body, such as temperature or light.

Internal stimulus

A change inside the body, such as blood glucose or water levels.

Nervous system

Detects changes and produces rapid responses to help maintain homeostasis.

CNS

Brain and spinal cord.

PNS

Nerves outside the brain and spinal cord.

Somatic nervous system

Controls voluntary movements.

Autonomic nervous system

Controls involuntary functions.

Sympathetic nervous system

Fight-or-flight; prepares the body for action.

Parasympathetic nervous system

Rest-and-digest; calms the body.

Neuron

A nerve cell that carries electrical signals.

Sensory neuron

Carries messages from receptors to the CNS.

Motor neuron

Carries messages from the CNS to effectors.

Synapse

The gap between neurons where signals are passed using neurotransmitters.

Reflex action

A rapid, automatic response to a stimulus.

Endocrine system

Glands that release hormones into the bloodstream.

Hormone

A chemical messenger released by a gland.

Insulin

Helps lower blood glucose.

ADH

Helps the body conserve water.

Adrenaline

Prepares the body for action during stress or danger.