The Nervous System
A Comprehensive Guide for Medical English Students
Structure • Function • Senses • Diseases • Instruments
Part 1 Structure of the Nervous System
1.1 Three Functions of the Nervous System
Detects changes (stimuli) inside and outside the body using sensory receptors.
Example: Feeling heat from a stove, seeing light, hearing sounds.
Processes and interprets sensory information, makes decisions.
Example: Brain recognises the stove is hot and decides "danger!"
Sends commands to muscles and glands to produce a response.
Example: Motor neurons tell your hand muscles to pull away from the stove.
1.2 Two Major Divisions
- Brain — the command centre
- Spinal cord — the main information highway
Protected by bone (skull & vertebral column), meninges (3 layers), and cerebrospinal fluid (CSF).
- All nerves outside the CNS
- 12 pairs of cranial nerves (from brain)
- 31 pairs of spinal nerves (from spinal cord)
Divided into: Somatic NS (voluntary), Autonomic NS (involuntary), Enteric NS (gut).
Nervous System Hierarchy
1.3 Meninges — Three Protective Layers
The brain and spinal cord are wrapped in three membranes called the meninges. Inflammation of these layers = meningitis.
1. Dura Mater Outermost
Tough, thick layer. Latin: "hard mother." Closest to the skull.
2. Arachnoid Mater Middle
Web-like layer (named after spider web). Contains CSF in the subarachnoid space.