Special Senses Nose

Special Senses- Nose

The special senses nose, a marvel of biological engineering, sits front and center on our faces, yet often goes unnoticed in its day-to-day workings. This remarkable organ, with its intricate structure and multifaceted roles, is a testament to the complexity and elegance of human anatomy. Serving as the gateway to our respiratory system and the primary organ for our sense of smell, the nose is a critical component of our health and sensory experience.

Table of Contents

Structure of nose

External structure of nose

Surface Appearance: The external nose has a pyramidal shape. The nasal root is located superiorly, and is continuous with the forehead. The apex of the nose ends inferiorly in a rounded ‘tip’. Spanning between the root and apex is the dorsum of the nose. Located immediately inferior to the apex are the nares (nostrils); piriform openings into the vestibule of the nasal cavity. The nares are bounded medially by the nasal septum, and laterally by the ala nasi (the lateral cartilaginous wings of the nose).

Skeletal Structure: The skeleton of the external nose is made of both bony and cartilaginous components:

Bony component: Located superiorly, it is comprised of contributions from the nasal bones, maxillae, and frontal bone.
Cartilaginous component: Located inferiorly, it is comprised of the two lateral cartilages, two alar cartilages, and one septal cartilage1. There are also some smaller alar cartilages present.

While the skin over the bony part of the nose is thin, that overlying the cartilaginous part is thicker with many sebaceous glands. This skin extends into the vestibule of the nose via the nares. Here there are hairs which function to filter air as it enters the respiratory system.

Muscles: A number of small muscles insert into the external nose, contributing to facial expression. All these muscles are innervated by branches of the facial nerve (CN VII).

Internal structure of nose

Nasal Cavities: Your nose has two nasal cavities, hollow spaces where air flows in and out. They are lined with mucous membranes. The cavities open anteriorly to the face through the two nares. Posteriorly the cavities communicate with the nasopharynx by two apertures called choanae.
Septum: The septum is made of bone and firm cartilage. It runs down the center of your nose and separates the two nasal cavities.
Turbinates (Conchae): There are three pairs of turbinates located along the sides of both nasal cavities. These folds inside your nose help warm and moisten air after you breathe it in and help with nasal drainage.
Sinuses: You have four pairs of sinuses. These air-filled pockets are connected to your nasal cavities. They produce the mucus that keeps your nose moist.
Nerve Cells: These cells communicate with your brain to provide a sense of smell.
Hair and Cilia: Hair and cilia (tiny, hairlike structures) inside your nose trap dirt and particles. Then they move those particles toward your nostrils, where they can be sneezed out or wiped away.

The nose is also made up of types of soft tissue such as skin, epithelia, mucous membrane, muscles, nerves, and blood vessels3. In the skin, there are sebaceous glands, and in the mucous membrane, there are nasal glands.

Functions of nose

Respiration: The nose allows air to enter and exit the body, serving as the primary passageway for respiration.
Filtration: The nose filters and cleans the air we breathe, removing particles and allergens. This is achieved through the action of cilia (tiny hair-like structures) and mucus.
Humidification and Warming: The nose warm and moisten the inhaled air, ensuring comfortable breathing. This is particularly important as it helps to prevent damage to the delicate tissues of the lungs.
Sense of Smell: The nose provides a sense of smell through various microscopic, specialized structures called the olfactory receptors in the inner lining of the nose.
Speech and Phonetics: The nose plays an essential role in speech and phonetics, affecting how we sound when we speak.
Memory: Interestingly, the nose also plays a role in memory. Certain smells can trigger vivid memories, linking our sense of smell to our ability to remember.

Nose disorders

Allergic Rhinitis: People with allergic rhinitis might cough, have watery eyes, and sneeze when they breathe in something they are allergic to. Common allergens include animal dander, dust, and pollen.
Deviated Septum: The nasal cavities are generally equal in size. A deviated septum occurs if the septum, or the bone and cartilage separating each nasal cavity, is off-center. This can lead to symptoms such as frequent sinus infections, noisy breathing, nosebleeds, and trouble breathing through one or both sides of your nose.
Nasal Polyps: These are noncancerous (benign) soft growths of tissue in your nasal passages or sinuses. The growths might not cause symptoms unless they are large and block your nasal passages.
Nosebleeds (Epistaxis): The only sign of an anterior nosebleed, the most prevalent type, is usually bleeding from one nostril.
Sinusitis: Sinusitis is one of the most common chronic conditions in the United States affecting fifty million Americans. It includes symptoms of nasal obstruction, nasal drainage, decreased sense of smell, facial pressure, and frequent sinus infections.
Loss of Smell (Anosmia): This is a condition where a person loses their sense of smell. It can be temporary or permanent and is often caused by a problem with the nose or brain.
Aspirin-Exacerbated Respiratory Disease (AERD): This is a chronic medical condition that consists of asthma, recurrent sinus disease with nasal polyps, and a sensitivity to aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs).
CSF (Cerebrospinal fluid) Leak: This is a condition that occurs when the cerebrospinal fluid (CSF) leaks through a defect in the dura or the skull and out through the nose or ear.

Conclusion

In conclusion, the human nose is a marvel of biological engineering and a testament to the complexity of human anatomy. It serves as the primary organ for our sense of smell, the gateway to our respiratory system, and plays a significant role in our speech and phonetics. Its intricate external and internal structures, each with their own unique functions, work together to ensure our well-being. From filtering the air we breathe to contributing to our sensory experiences, the nose performs a multitude of tasks that often go unnoticed. Furthermore, understanding the various disorders that can affect the nose underscores its importance and the need for its care.