Sense Of Smell May Haidy 12 B Introduction

Sense Of Smell May & Haidy 12 B

Introduction Smell, or olfactory sense is often our first response to stimuli. It alerts us to fire before we see flames, and makes us recoil before eating rotten food. Although it is a basic sense, scientists are still studying how exactly odorants are picked up, processed, and interpreted as smells. Smell is detected by chemoreceptors, when these are stimulated, an impulse is passed on to the brain.

How it works In order to smell something, molecules from it have to make it to our nose. Everything we smell is giving off molecules, these molecules are light, volatile (easy to evaporate) chemicals that float through the air to our nose. These molecules become dissolved in the mucous lining of our nasal conchae. The molecules then come into contact with a patch of bipolar olfactory neurons located at the top of our nasal passages. The odor molecules bind to these receptors sites. The receptor cites are neurons that have cilia at the end of their dendrites. The cilia are the chemoreceptors mentioned earlier. The olfactory neurons transmit the impulse along their axons whose ends become enlarged olfactory bulbs.

continuation There, they connect with the area of the brain called the olfactory cortex found in the temporal and frontal lobes of the cerebrum. The brain then interprets these receptor combinations into a type of olfactory code. The exact mechanism of how this works is still being investigated by biologists. olfactory receptors rapidly adapt to odors and after a short time, we no longer perceive the odor as intensely as it was initially detected. Our sense of smell is complex because a small number of receptors detect a great variety of odors.

Smell Disorders: Hyposmia: a reduced ability to detect odors. Anosmia: complete inability to detect odors. In rare cases, someone may be born without a sense of smell, a condition called congenital anosmia. Parosmia : change in the normal perception of odors, such as when the smell of something familiar is distorted, or when something that normally smells pleasant now smells foul. Phantosmia: the sensation of an odor that isn’t there.

https: //www. youtube. com/watch? v=sn. Jn. O 6 Opj. Cs

References: http: //www. sirc. org/publik/smell_human. html https: //www. nidcd. nih. gov/health/smell-disorders http: //www. webmd. com/a-to-z-guides/rm-quiz-sense-of-smell