Chemicals Can Be Smelled if They Reach the

February 16, 2022 Post a Comment

Smell - The Nose Knows

The smells of a rose, perfume, freshly baked bread and cookies...these smells are all made possible because of your nose and brain. The sense of smell, called olfaction, involves the detection and perception of chemicals floating in the air. Chemical molecules enter the nose and dissolve in mucous within a membrane called the olfactory epithelium. In humans, the olfactory epithelium is located about vii cm up and into the nose from the nostrils.

The Olfactory System

Hair cells are the receptors in the olfactory epithelium that respond to particular chemicals. These cells accept small hairs called cilia on one side and an axon on the other side. In humans, in that location are about 40 million olfactory receptors; in the High german Shepherd dog, there are about 2 billion olfactory receptors.

No i knows what actually causes olfactory receptors to react - it could be a chemical molecule's shape or size or electrical charge. The electrical activity produced in these hair cells is transmitted to the olfactory bulb. The information is then passed on to mitral cells in the olfactory bulb.

The olfactory tract transmits the signals to the brain to areas such every bit the olfactory cortex, hippocampus, amygdala, and hypothalamus. Many of these brain areas are role of the limbic system. The limbic organisation is involved with emotional behavior and memory. That'due south why when you smell something, it often brings back memories associated with the object.

As you lot probably know, when you lot have a common cold and your nose is stuffed up, yous cannot smell very well. This is considering the molecules that carry odour cannot reach the olfactory receptors.

Did you lot know?

About 2 million people in the Usa take NO sense of smell. This disorder is chosen anosmia. A serious head injury tin can cause anosmia. Most likely this results in damage to the olfactory nerves as they enter the olfactory bulb. It is also possible that impairment of the frontal lobes caused by a tumor or surgery tin cause anosmia. Elderly people ofttimes have a reduced sense of smell.
People are very sensitive to the smell of light-green bell pepper. This smell can be detected when it is mixed with air at simply 0.five parts per trillion!
Natural gas, which many people use to heat their homes and to cook, is odorless. Because natural gas is unsafe to breathe and is explosive, information technology is important for people to be able to observe a gas leak. That is why gas companies add a evil-smelling ("rotten egg smell") chemic called mercaptan to natural gas.
1 in ane,000 people are insensitive to butyl mercaptan, the stinky odor of skunks.

For more information about the sense of smell, run into:

Following Our Noses - from Time Magazine, March 23, 1998 - Other animals tin communicate volumes through odour. Now information technology appears nosotros tin too.
Seeing, Hearing and Smelling the Earth
ChemoReception Web - Taste and Odour
Chemoreception - Monell Chemic Senses Middle

An infographic summarizing information and statistics on the sense of smell in U.S. adults over age 40.