Use precise geolocation data. Select personalised content. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. Actually a pair of cranial nerves, the olfactory nerve transmits information to the brain from smell receptors in the nose. The olfactory nerve is sometimes referred to as the first cranial nerve, or CN1.
Cranial means "of the skull. The olfactory nerve is the shortest nerve in the human head. It originates in the olfactory mucosa mucous membrane along the roof of your nasal cavity nostril. This nerve is made of many small nerve fibers called fascicles that are bound together by thin strips of connective tissue.
The bundle extends from the nasal cavity through the ethmoid bone behind your nose. From there, the fascicles go inside a structure called the olfactory bulb. You have a bulb for each nostril, and they send the information along what's called the olfactory tract and into the brain.
These impulses go to several regions of your brain, including the:. Unlike many other nerves, the olfactory nerve has one job—making you able to smell things. When particles in the air enter your nasal cavity, they interact with the receptors on the olfactory nerve and a type of tissue called the olfactory epithelium, which is in several areas of the nasal cavity and contains millions of receptors.
All those receptors then send that information they've gathered to the central nervous system. Your brain then interprets that information as scent.
A number of conditions can interfere with your sense of smell, as can an injury. These can cause a reduced or completely lost sense of smell, phantom smells, or even a heightened sense of smell. The following terms are used to describe certain symptoms associated with disordered odor perception:. Changes to your sense of smell have a big impact on your sense of taste, as well.
The most common condition to impact the olfactory nerve is the common cold, but other viral illnesses can have the same effect. You probably know that when nasal congestion fills your sinuses, it can result in a lowered ability to smell that comes back after the congestion clears up.
Sometimes, though, it takes a while to come back all the way. This is called post-viral olfactory loss PVOL , and everyone probably experiences it at some point. Researchers don't understand exactly why this happens, but they suspect it's because certain viruses—including the common cold and influenza —somehow damage the mucous membrane and the olfactory epithelium. Some people will have a sudden and noticeable drop in smell sensitivity. In others, it's a gradual loss over the course of several acute illnesses which most people get a few times a year.
Anosmia or hyposmia can result from a head injury, which is called post-traumatic olfactory loss PTOL. The loss is connected to both the severity of the injury as well as the part of the head that's damaged. Injuries to the back of the head are the most likely ones to cause loss of smell. That might seem odd since the olfactory nerves are in the front of the brain. When there's an impact on the back of the head, the brain can come forward and collide with the inside front of the skull—right where the olfactory nerve is.
Then, as the brain bounces back, it yanks on the delicate nerve fibers, which can snag on the rough edges of the tiny holes in the skull that they extrude through. The olfactory nerves can become severed in this way, but often the smell loss is due to bruising of the olfactory bulb. The nasal cartilages provide structure and support to the nose. They are primarily composed of hyaline cartilage, which is densely packed with….
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