How Does the Nose Function?

Introduction:

The nose is an important organ as it helps in breathing. It is the main gateway into the respiratory system. It contributes to the physical appearance of a person as it is the most prominent feature of the face. It not only helps smell things, but it plays an important role in tasting food as well. The nose helps in identifying the odors from the food and enhances the eating experience. Try eating while pinching the nose; it will barely taste like anything. It even helps in identifying burning smells that can save from accidents like fires. That is how important the nose is. The brain, the master organ of the body, plays an important role in regulating the function of the nose. This article explains how the brain regulates these functions.

What Is the Anatomy of the Nose and Its Adjacent Organs?

The nose is the first part of the respiratory system. The air enters through the nose via the nostrils (two round holes separated by a thin cartilage called the nasal septum) and gets filtered and moistened to enter the lungs comfortably. At the back of the nose is the olfactory epithelium, the main organ of the olfactory system (structures that sense smell). A small yellowish patch of tissue is on the roof of the nasal cavity. The olfactory epithelium consists of multiple neurons (nerves) lined inside. These neurons have receptors present in them. These sensory receptors will receive odors from the nose and send impulses to the olfactory lobes present inside the brain. Each receptor has an affinity for one type of smell. Scientists have stated that more than 40 million olfactory receptors help identify over 10,000 smells.

What Are the Different Disorders Related to the Sense of Smell?

• Anosmia is the complete loss of sense of smell.

• Hyposmia is a reduced ability to smell.

What Are the Olfactory Lobes?

They are small, club-shaped structures in the anterior (front) portion of the brain. They are involved in olfaction, or the sense of smell. The olfactory lobes consist of various neurons that help in olfaction. Any damage to the olfactory bulb will lead to anosmia, that is, complete loss of sense of smell.

What Happens in the Brain When We Smell?

Certain nerves supply every part of the body. These nerves carry messages to and from the organs to the brain and spinal cord. Similarly, the nose is supplied by a special nerve called the olfactory nerve, the first cranial nerve (nerves that arise from the brain and spinal cord). The olfactory system consists of an olfactory bulb supplied by the olfactory nerve. The olfactory receptors receive airborne molecules from the odors and transfer them to the olfactory bulb.

The olfactory nerve carries electrical impulses from the olfactory epithelium to the brain. The brain then processes these impulses and sends impulses back, which help to identify the smell. Whenever we smell something, the part of the brain associated with the odor gets activated, and the individual experiences a variety of smells and emotions when smelling food.

Odors are directed to the limbic system. The limbic system is a part of the brain that regulates the behavior and emotions of a person. So when a person inhales something, a person not only smells it but emotions and memories associated with it are also refreshed in the brain as the limbic system has the memory to remember different scents.

What Are the Diseases Associated With the Nose?

The nose can be an entry point for various bacteria and viruses that can cause infections. The following diseases are related to the nose -

• Common Cold - It can be due to a virus or any irritant in the nose. It can cause a runny or blocked nose, sneezing, and irritation.

• Epistaxis or Nosebleeds - The nose bleeds when there is a breakage in any blood vessel of the nose.

• Nasal Polyps - They are bumps present in the nose that block the airflow and make filtering air difficult.

Which Neurological Diseases Affect the Ability to Smell?

A declining ability to smell can be an early sign of developing neurodegenerative disease.

Individuals with the following conditions may experience a loss of sense of smell -

1. Parkinson’s Disease - Patients with Parkinson's may suffer from hyposmia (reduced sense of smell). This condition is associated with damage to neurons in the brain. When the nerves associated with the sense of smell get damaged, it affects the ability to smell.

2. Alzheimer’s Disease - Anosmia (loss of smell) is an early sign of Alzheimer-related cognitive impairment.

3. Multiple Sclerosis - This is a disorder in which the immune system of the body attacks the protective covering of the neurons leading to nerve damage. Impairment in odor identification is a symptom of advanced multiple sclerosis.

How to Care for the Nose?

• The nose must be kept clean at all times. Rinse the nose with warm water and never blow the nose harshly.

• The nose hair must not be plucked aggressively as these hairs filter the air that enters the nose.

• Abstain from smoking.

• Cover the nose when entering polluted areas. Never breathe in direct smoke from vehicles.

• Normal saline water rinses can flush out dirt and toxins from the nose. This even helps to release mucus.

• A humidifier can be used in the house to keep the air warm and moist.

Conclusion:

The nose is an important organ, and it performs various vital functions. It has a unique connection with the brain. The sense of smell is not only for smelling food but also for tasting different food items and distinguishing flavors. The sense of smell also alerts a person about different dangerous situations and can save them from such calamities. There is an altered sense of smell in several neurological disorders, and this is an irreversible condition. Hence, smell is a critical sense that is important to all.