The nose is the only way for the air to enter the lungs. It is the primary organ for filtering particles from inhaled air.
They also play a vital role by providing first-line immunologic defence by bringing inspired air in contact with mucous membranes possessing immunoglobulin A (IgA).
What is Nose?
The nose is the first organ in the upper respiratory tract of the human respiratory system.
The nose is the prominent structure between the eyes that serves as the respiratory tract's entrance and houses the olfactory organ.
It supplies air for breathing, serves as the sense of smell, conditions the air by filtering, warming and moistening and cleanses itself of debris extracted from inhalations.
Parts of the nose
Bones and cartilages render the shape of the nose. Nasal anatomy includes both the external and internal structures of the nose.
The three sections of the external nose are the frontal, lateral and basal views. The nose is supported in the upper frontal region by two nasal bones that form the nose's bridge.
Bone
The nasal bone is a small, flat skull bone. It is part of the facial skeleton and provides support for the nose bridge.
Mucous membrane
The nose, sinuses and throat are all lined with a mucous membrane. This membrane humidifies and warms the air we breathe.
It also produces a sticky mucus that keeps dust and other small particles from entering the nose. Cilia are hair-like structures that work with mucus to trap foreign particles that enter the nose while breathing.
Nasal cavities
The nasal cavity is the empty, hollow space through which air flows. It is divided into two parts known as nasal passages. While breathing, air passes through these passages.
Nerve cells
The olfactory nerve is a pair of cranial nerves. They transmit information from smell receptors in the nose to the brain.
Nostrils
Nostrils are either of two external openings of the nasal cavity.
Septum
The septum separates the two chambers of the nose. It is a thin bone and cartilage wall.
Sinuses
Sinuses are hollow, air-filled chambers in the bone surrounding the nose. The sinuses send mucus into the nasal cavity.
Turbinates
Turbinates are tiny structures inside the nose that clean and humidify the air entering the lungs through the nostrils.
The external nose
The external nose is a prominent feature of the face that projects out. It has an entrance to the nasal cavity. The shape of the external nose is compared to that of a pyramid.
The external nose's skeleton is composed of both bony and cartilaginous components.
The nasal root is located superiorly and connects to the brow. The nose's apex terminates inferiorly in a rounded tip. The dorsum of the nose extends between the root and the apex.
The nares or the nostrils are openings into the nasal cavity located immediately inferior to the apex. The nasal septum and the ala nasi border the nostrils medially and laterally.
What is the function of the nose?
Inhaling oxygen and exhaling carbon dioxide are the primary functions of the nose. Interestingly, they also contribute to tasting and hearing.
Helps in inhalation
The process of respiration commences from the nose. During inhalation, oxygen enters the nose via the nostrils.
The nasal cavities connect to the choana, which connects to the nasopharynx. The air then enters the oropharynx before travelling to the lungs through the larynx, trachea and bronchi.
Contributes to the look and sound of a person
The nose has a significant impact on the overall symmetry of the face. Too small nose makes a face appear flat and broad. A large nose makes the chin less appealing and overshadows other features.
The sound of a human relies heavily on nasal cavity resonance. Sound travels through the nose rather than the pharynx during speaking or singing, and the nasal cavities resonate with sound, amplifying the voice.
Filters and cleans the inhaled air
The nasal cavity walls are covered with hair or cilia. These hair-like structures, along with mucus trap dust and harmful particles and purify the inhaled air.
The cilia's back and forth movement aids in the movement of dust particles to the throat, where they are swallowed or excreted through the nasal cavity.
Warms and moistens the air
The nose hair humidifies and warms the inhaled air before moving to the lungs for gas exchange.
The heat and moisture in the carbon dioxide are absorbed by the nasal hair and released into the atmosphere during exhalation.
The spiral-shaped nasal conchae keep the air whirling within the nasal cavity for a more extended period of time, ensuring that it is properly humidified and purified.
Provides a sense of smell
The nose is an organ of smell because of olfactory sensory neurons. These are found in a small patch of tissue deep inside the nose, which is responsible for the sense of smell.
Sense of taste
Food releases chemicals that travel up to the nose and activate the olfactory receptors inside the nose while chewing. They collaborate with the taste buds to determine the actual flavour of the food.
What are sinuses?
Sinuses are air pockets present within the bones of the skull and face that are linked to the nasal passages through small channels or tubes known as the osteomeatal complex.
These channels allow air to flow from the nose into the sinuses and mucus to drain from each sinus into the nose.
Types of sinuses
Sinuses are found in the bones of our skull. Each sinus is named after the bone in which it is located.
Ethmoid sinus
The ethmoid sinus is found inside the face, near the bridge of the nose. It is present from birth and continues to develop with age.
Maxillary sinus
The maxillary sinus is situated near the cheeks inside the face. It is also present at birth and grows over time.
Frontal sinus
The frontal sinus is situated near the brow from the inside. It does not appear until about the age of seven.
Sphenoid sinus
The sphenoid sinus is located deep in the face behind the nose. It usually does not appear until the adolescent years.
What are muscles?
The nose muscles are a subset of the facial muscles. Numerous small muscles insert into the external nose and help with facial expression and respiration. All these muscles are innervated by facial nerve (CN VII) branches.
Procerus muscle
The procerus muscle arises from the fascia that covers the nasal bone and lateral nasal cartilage and inserts into the lower forehead. Contraction can lower the medial brows and wrinkle the superior dorsum skin.
Nasalis muscle
The procerus muscle is assisted in this action by the transverse portion of the nasalis muscle. Concurrently, the nasalis alar part emerges from the maxilla and inserts into the major alar cartilage. This allows the muscle to dilate and flare the nares. The depressor septi nasi aids in this action.
Conditions & disorders of the nose
Allergic rhinitis
Rhinitis is most commonly known as allergic rhinitis. It is a nasal membrane inflammation characterised by sneezing, nasal itching, nasal congestion and rhinorrhea.
Although allergic rhinitis is not life-threatening (unless accompanied by severe asthma or anaphylaxis), the condition can cause significant morbidity.
Allergic rhinitis occurs when the nose is irritated by an allergen such as pollen. Most people can be treated with regular over-the-counter medications.
Deviated septum
The nasal septum is the thin wall that separates the left and right nasal passages. When the nasal septum is displaced to one side, it results in a deviated septum.
An injury to the nose is a common cause of septum deviation. A condition present at birth can lead to a deviated septum.
A deviated septum rarely occurs when the foetus develops in the womb and is visible at birth.
Enlarged turbinates
Turbinate hypertrophy is an abnormal growth or enlargement of the turbinates and the bony structures inside the nose.
Allergies or a cold can irritate them, causing them to swell or enlarge. The swelling makes it difficult to breathe. Overuse of decongestant nasal sprays is another cause of the swelling.
If the turbinates are swollen, the doctor may prescribe medication to reduce the swelling, which includes a nasal corticosteroid and nasal antihistamine sprays. Surgery may be required if enlarged inferior turbinates cause nasal obstruction.
Nasal trauma
Nasal trauma is a common injury that can cause varying degrees of damage to any of the structural components of the nose like the skin, bone or cartilage.
The vast majority of nasal fractures are isolated injuries. Examples of common nasal trauma include nose fracture, nosebleeds, chemical irritation or injuries on the inside of the nose and foreign object obstruction.
Sinus infection
Sinusitis is the swelling or inflammation of the sinuses.
Sinuses are located within the bones surrounding the nose, which secrete mucus that drains through the nose.
An infection or another problem could be the source of the disease.
When the nose swells, it can block the sinuses and cause pain. A usual cold, allergic rhinitis, nasal polyps and a nasal cavity shift due to a deviated septum are conditions that can cause sinus blockage.
Nasopharyngeal cancer
Nasopharyngeal cancer is a rare form of cancer that affects the area of the throat between the back of the nose and the pharynx (the back of the mouth).
A lump in the upper part of the neck is usually the first sign of nasopharynx cancer. Other signs and symptoms could be swelling of the neck, congestion in the nose, nosebleeds and chronic headache.
The usual treatment for nasopharyngeal cancer is radiation therapy combined with chemotherapy, known as chemoradiation.
Nasal polyps
Nasal polyps are abnormal growths of the soft, swollen and sac-like inflamed tissue. They are found on the inside of the nose or in the sinuses.
In some cases, nasal polyps can be due to chronic rhinosinusitis and co-occur together. The sinuses and nasal cavity are inflamed for more than 4 to 12 weeks in this condition. However, not everyone with this condition will develop nasal polyps.
People with asthma, aspirin sensitivity, cystic fibrosis, allergic rhinitis and chronic sinus infection are more prone to developing nasal polyps.
Nasal valve collapse
The nasal valve is a small opening in the nose through which air flows. Nasal valve collapse occurs when this passage becomes obstructed. When the nasal valve weakens or narrows further, it can block airflow and make breathing difficult.
Nosebleed
A nosebleed is medically termed epistaxis. Nasal bleeding can either be caused spontaneously or by trauma or nose picking.
Dry air is usually the cause of nosebleeds. Blood flows from one or both nostrils during a nosebleed. It can be light or heavy, and its duration can range from a few seconds to 15 minutes or more.
How can I keep my nose healthy?
Avoid secondhand smoke
Secondhand smoke is a real threat. According to CDC (Centers for Disease Control and Prevention), the nonsmokers exposed to secondhand smoke have a 25-30% increased risk of developing heart disease. It also raises the risk of stroke by 20-30%.
Secondhand smoke exposure elevates the risk of lung cancer and many other types of cancer by up to 30%, says an article from NCBI. Therefore, avoiding secondhand smoke is recommended.
Don't remove nose hairs
Nose hairs serve as a defence mechanism, keeping harmful debris out of the nose by filtering them. Once the hair follicle is open, all germs, dirt and particles in the surrounding area will be drawn to the open pore after plucking.
Most importantly, an infection can also transfer from the blood vessels to the brain through nasal hair removal. Not removing nose hairs protects from unwanted health issues.
Drink plenty of water
Plenty of water is required to keep the mucus in the nose, sinus and respiratory passage thin and flowing. This will also keep mucous from accumulating in the sinuses and lungs.
Keep your home clean
Home is where everyone spends the majority of their leisure time. The house can be kept clean to prevent breathing a high amount of dust and other allergens.
Squirt saline into the nasal cavities
A saline nasal wash aids in the removal of pollen, dust and other dirt from the nasal passages. It also helps in the removal of excess mucus and provides adequate moisture. Moist and clean nasal cavities are possible by squirting saline.
Use a humidifier at home
Using a humidifier in the home helps relieve a stuffy nose and break up mucus so it can be coughed up. It also keeps the air moist.
Cold and flu symptoms can be alleviated by breathing in humidified air.
Conclusion
The nasal cavity warms, humidifies, filters and serves as a conduit for inspired air. It also protects the respiratory tract through mucociliary clearance.
The pleasant and beautiful aroma and the nasty smell we sense are due to the nose's olfactory receptors.
If any of the nasal cavity's functions are compromised, the result will likely be signs and symptoms of clinically significant disease processes. A healthy nasal cavity is critical for preventing major effects.
FAQs
What is the anatomy of the nose and sinuses?
· Nostrils
· Cilia
· Nasal cavities
· Septum
· Nerve cells
· Turbinates
· Mucous membrane
· Sinuses - There exist four pairs of sinuses in every human. These are maxillary sinuses, frontal sinuses, ethmoid cells and sphenoid sinuses.
How does nose anatomy work?
Sinuses produce mucus that moistens the nose. Turbinates in the nose warm and humidify the inhaled air. They are also vital for nasal drainage.
