The 12 cranial nerves are a set of nerves that originate in the brain and provide motor and sensory functions to the head and neck. Each cranial nerve has a different function responsible for sense or movement. They include:

1. Olfactory nerve (CN I): essential for detecting smells.
2. Optic nerve (CN II): enables a person to see.
3. Oculomotor nerve (CN III): helps control eye movement and blinking.
4. Trochlear nerve (CN IV): helps move the eyes up and down or back and forth.
5. Trigeminal nerve (CN V): responsible for sensations in the face and cheeks, taste, and jaw movements.
6. Abducens nerve (CN VI): helps move the eyes.
7. Facial nerve (CN VII): controls facial expressions and sense of taste.
8. Vestibulocochlear nerve (CN VIII): responsible for hearing and balance.
9. Glossopharyngeal nerve (CN IX): responsible for taste, somatosensory information from the tongue, tonsil, pharynx, and controls some muscles used in swallowing.
10. Vagus nerve (CN X): responsible for sensory, motor, and autonomic functions of viscera (glands, digestion, heart rate).
11. Accessory nerve (CN XI): controls muscles used in head movement.
12. Hypoglossal nerve (CN XII): controls muscles of the tongue.

The functions of the cranial nerves are sensory, motor, or both. Sensory cranial nerves help a person see, smell, and hear. Conversely, motor cranial nerves help control muscle movements in the head and neck. Doctors can identify neurological or psychiatric disorders by testing cranial nerve functions.