Olfactory nerve

Olfactory nerve

The olfactory nerve, also known as cranial nerve I, is the first of twelve cranial nerves and is instrumental in the sense of smell. Unlike most of the cranial nerves, the olfactory nerve is a sensory nerve that contains only sensory afferent fibers, which transmit impulses to the brain from the smell receptors located in the nasal cavity.

Anatomy

The olfactory nerve is the shortest of the twelve cranial nerves and only one of two cranial nerves (the other being the optic nerve) that do not join with the brainstem. It originates in the olfactory epithelium, a small patch of tissue at the base of the nasal cavity, and runs through the cribriform plate of the ethmoid bone into the olfactory bulb.

Function

The primary function of the olfactory nerve is to carry smell information from the nasal cavity to the brain. This is accomplished through the detection of chemical substances (odorants) in inhaled air that bind to receptors on the olfactory sensory neurons. These signals are then transmitted to the olfactory bulb and subsequently to other parts of the brain for further processing.

Clinical significance

Damage to the olfactory nerve can result in a loss of smell, a condition known as anosmia. This can occur as a result of head trauma, infection, or other causes. In some cases, a damaged olfactory nerve can also lead to a distorted sense of smell, known as parosmia.

See also

• Cranial nerves
• Olfactory system
• Anosmia
• Parosmia