The brain is primarily supplied by the twelve cranial nerves, which handle various sensory and motor functions. These nerves can be categorized by their origin within the brain.
Cranial Nerves Supplying the Brain
There are twelve cranial nerves in total, each serving specific functions and originating from different parts of the brain. Here's a breakdown:
- The olfactory and optic nerves (I and II) originate from the anterior part of the brain.
- The remaining ten cranial nerves (III-XII) – oculomotor, trochlear, trigeminal, abducent, facial, vestibulocochlear, glossopharyngeal, vagus, accessory, and hypoglossal nerves – originate from the brainstem.
Table of Cranial Nerves
| Cranial Nerve | Number | Origin |
|---|---|---|
| Olfactory | I | Forebrain |
| Optic | II | Forebrain |
| Oculomotor | III | Brainstem |
| Trochlear | IV | Brainstem |
| Trigeminal | V | Brainstem |
| Abducent | VI | Brainstem |
| Facial | VII | Brainstem |
| Vestibulocochlear | VIII | Brainstem |
| Glossopharyngeal | IX | Brainstem |
| Vagus | X | Brainstem |
| Accessory | XI | Brainstem |
| Hypoglossal | XII | Brainstem |
Functions of Cranial Nerves
The cranial nerves perform various functions, including:
- Sensory functions: Smell (olfactory), vision (optic), taste (facial, glossopharyngeal, vagus), hearing and balance (vestibulocochlear).
- Motor functions: Eye movement (oculomotor, trochlear, abducens), facial expression (facial), swallowing (glossopharyngeal, vagus, accessory, hypoglossal), tongue movement (hypoglossal), and head and shoulder movement (accessory).
- Mixed functions (both sensory and motor): Trigeminal (facial sensation and chewing), glossopharyngeal (taste and swallowing), vagus (parasympathetic control of organs).
