The Journey of Smell to the Brain
Smells activate special cells inside your nose that then send signals to your brain.
Olfactory Sensory Neurons
Substances around you release invisible odor molecules that activate olfactory sensory neurons high inside your nose.
Olfactory Bulb
These neurons send a unique pattern of signals to an area in your brain called the olfactory bulb.
Brain
Your brain uses those signals to identify specific smells.
Not everyone has a good sense of smell.
Changes to your sense of smell may be caused by:
- Aging
- Viruses
- Smoking
- Head injuries
- Sinus inflammation and upper respiratory infections
- Conditions that affect the nervous system
Smell disorders are more common as you get older.*
- 4% of people aged 40-49 have smell disorders
- 11% of people aged 50-59 have smell disorders
- 13% of people aged 60-69 have smell disorders
- 25% of people aged 70-79 have smell disorders
- 39% of people over age 79 have smell disorders
Some people may have a specific type of smell disorder.
Hyposmia:
a reduced ability to detect odors
Anosmia:
the complete inability to detect odors
Parosmia:
a change in the normal perception of odors
Phantosmia:
the sensation of odor that isn’t there
Having problems with your sense of smell? Talk to your doctor. Learn more.
Sources: Smell Disorders: https://www.nidcd.nih.gov/health/taste-smell
*U.S. National Health and Nutrition Examination Survey. Analysis reported in Reviews in Endocrine and Metabolic Disorders (2016).