The Nervous System
This domain tests basic neuroanatomy and how nervous system function shapes pilot performance: central versus peripheral organisation, autonomic arousal, sensory integration and the effects of hypoxia, fatigue and drugs.
Organisation
- Central nervous system (CNS): brain and spinal cord - integration, memory, judgement and motor control.
- Peripheral nervous system: somatic nerves (voluntary movement and sensation) and autonomic nerves (involuntary control).
- Autonomic divisions: sympathetic (fight-or-flight - heart rate, blood pressure, pupil size, blood flow to muscles) and parasympathetic (rest-and-digest, vagal slowing of the heart).
- Neurons communicate across synapses by neurotransmitters; fatigue, hypoxia, alcohol and some drugs slow or distort transmission.
Why it matters in flight
- Neurons are highly oxygen-dependent; hypoxia impairs judgement and vision before conscious collapse, so a pilot may not recognise the deficit.
- Sympathetic arousal is useful for rapid action but narrows attention and degrades fine motor control; recognising it allows deliberate control.
- The brain integrates visual, vestibular and proprioceptive signals. When they conflict, disorientation results, so instrument cross-check is the reliable override.
- Pain, emotion and fatigue alter perception and reaction time.
Worked example
A pilot's heart rate and breathing rise after an engine warning. That is sympathetic activation: useful for immediate action, but it can cause fixation and rushing. The pilot should consciously slow the scan, use a checklist and verbalise actions, converting arousal into controlled performance rather than allowing it to narrow attention.
Traps that cost marks
- Treating adrenaline as a separate system rather than part of sympathetic activation.
- Placing peripheral nerves inside the CNS.
- Assuming arousal always improves performance; beyond an optimum it degrades it.