Question

Test 2: Olfactory adaptation

1. Obtain two smelly objects, such as a bottle of oil of peppermint, black walnut extract, isopropanol, or anything else that has a strong odor.
2. Press one nostril closed.
3. Hold one of the smelly objects under the open nostril.
4. Record the time it takes or the odor to disappear.
5. Repeat with the other nostril and note the time to adaptation.
6. Immediately remove the first smelly object and replace it with the second, which should smell very different, hopefully ☺
7. Answer the following questions:
   1. What smelly objects did you use? How long did it take to become adapted to the first smell in the first nostril? How long did it take to become adapted when you changed nostrils? Was it longer or shorter? Why?
   2. What happened when you replaced objects? Why?

Answer 1

1

Answer :- Peppermint oil , Clove oil.

.Fragrance Right Nostril Fatigue - Clove Oil 1:22, Peppermint Oil 1:38 (min and sec).

Left Nostril Fatigue - Clove Oil 1:15 , Peppermint Oil 1:45 (min and sec).

Olfactory sensory neurons rapidly adapt to repetitive odorant stimuli. In the human body, specialized nerve cells respond to conditions in the environment and send a signal through other nerve cells to the brain. These specialized nerve cells have structures called sensory receptors, structures that will only respond to a specific kind of stimulus. For each type of receptor, nerve cells provide information in the same “all or nothing” manner. A stimulus is either sufficient to cause a cell to fire, transmitting a nerve impulse to the brain or spinal cord, or it is not.

Nerve impulses travel through nerve fibers to the brain, where the impulses are processed. By analyzing all the inputs from the sense organs, the brain interprets the appropriate responses, which we perceive as seeing, feeling, hearing, smelling, and tasting. If an injury causes the nerves in a sense organ to be damaged or severed, the brain can no longer obtain accurate information from that nerve, even if the sense organ is healthy and might be receiving impulses from stimuli.

Also  initially the odor of food is often perceived as being very strong, but after time the awareness of the odor normally fades to the point where the smell is not perceptible or is much weaker. After leaving the area of high odor, the sensitivity is restored with time. Anosmia is the permanent loss of the sense of smell, and is different from olfactory fatigue.

ii

The nose remains immediately sensitive to any new or different odor.

Smell an odour for long enough, we eventually stop noticing it. This is because prolonged exposure to a strong smell is believed to saturate the olfactory epithelium with odour molecules to the point where information is no longer delivered to the brain. This is called 'adaptation'. Loss in smell sensitivity is only temporary and is particular to that 'over-smelled' odour. Recovering from adaptation depends on the individual but can range from a few seconds to a couple of minutes. The total convergence ratio is 1000:1 and has the important role of increasing the sensibility of the olfactory signal that will be sent to the specialized areas in the brain .So nose remains immediately sensitive to any new or different odor