Olfactory nerve

src: www.earthslab.com

The olfactory nerve is usually regarded as the first cranial nerve, or just CN I , which contains sensory nerve fibers associated with odors.

Afferent nerve fibers from the olfactory receptor neurons send nerve impulses about the smell to the central nervous system, where they are perceived by the sense of smell (smell). Derived from the embryo nose plasode, the olfactory nerve is somewhat unusual between the cranial nerves because it is capable of some regeneration if damaged. The olfactory nerve is sensory and comes from the olfactory mucosa at the top of the nasal cavity. From the olfactory mucosa, the nerves (actually many small nerve nerves) propagate through the cribriform plate from the ethmoid bone to reach the surface of the brain. Here the phallicles enter the olfactory and synaptic bulb there; of the tuber (one on each side) the olfactory information is transmitted to the brain through the olfactory channel. The fascicles of the olfactory nerve are not visible in the cadaveric brain as they break up after lifting.

Video Olfactory nerve

Structure

The olfactory neuron special olfactory nerve receptor is located in the upper olfactory mucosa of the nasal cavity. The olfactory nerve consists of a large collection of sensory nerve fibers extending from the olfactory epithelium to the olfactory bulb, passing through many cribriform plate openings, a structure similar to ethmoid bone sieves.

The sense of smell arises from the stimulation of receptors by small molecules in the air of inspiration from various spatial, chemical, and electrical properties that reach the nasal epithelium in the nasal cavity during inhalation. These stimuli are transduced into electrical activity in the olfactory neurons, which then transmit the impulses to the olfactory bulb and from there to the rest of the central nervous system through the olfactory channel.

The olfactory nerve is the shortest of the twelve cranial nerves and, similar to the optic nerve, is not derived from the brain stem.

Maps Olfactory nerve

Function

Afferent nerve fibers from the olfactory receptor neurons send nerve impulses about the smell to the central nervous system, where they are perceived by the sense of smell (smell).

The functional components of the olfactory nerve include a special visceral afferent (SVA), which carries the odorous modality.

src: i.ytimg.com

Clinical interests

Checkout

Damage to this nerve damages the sense of smell. To simply test the function of olfactory nerves, each nostril is tested with a strong odor. If the odor smells, the olfactory nerve is likely to function. On the other hand, nerves are just one of several reasons that can explain if the odor is not smelled. There is an olfactory testing package in which a strong odor is embedded into the card and the patient's response to any odor can be determined.

Lesions

Lesions in olfactory nerves may occur due to "blunt trauma", such as coup-contrecoup damage, meningitis, and tumors in the frontal lobe of the brain. These injuries often lead to reduced ability to feel and smell. Lesions in the olfactory nerve do not cause a decrease in the ability to feel pain from the nasal epithelium. This is because the pain of the nasal epithelium is not brought to the central nervous system by the olfactory nerve - it is brought to the central nervous system by the trigeminal nerve.

Aging and odor

Decreased olfactory abilities are a normal consequence of human aging, and are usually more pronounced in men than in women. It is often not recognized in patients except that they may note a decrease in the ability to taste (many flavors are actually based on the acceptance of food odors). Some of this decrease results from repeated damage to olfactory nerve receptors because of the possibility of recurrent upper respiratory tract infections. People with Alzheimer's disease almost always have an abnormal olfactory when tested.

src: anatomyclass01.us

Additional images

src: www.indymedia.org.uk

See also

• Phantosmia
• Anterior olfactory nucleus

src: anatomyclass01.us

Note

src: bmc.med.utoronto.ca

External links

• "1-1". Cranial Nerve . Yale Medical School. Archived from the original in 2016-03-03.
• cranialnerves at The Anatomy Lesson by Wesley Norman (Georgetown University) ( I )
• Notes on Olfactory Nerves

Source of the article : Wikipedia