THE NOSE
The nose is a vital respiratory organ. The nose acts as the primary means of air passage for the human body. The nose is also a sense organ. Moreover, the nose is an important apparatus of the human voice box.
MEMBRANE
LOCATION OF THE NOSE
The nose is the uppermost portion of the human respiratory structure. The nose is basically a hollow structure. Nonetheless, the interior layout of the human nose is quite complex.
FUNCTIONS OF THE NOSE
The hollow cavity of the nose acts as an air moistening and warming apparatus. At the openings of the nasal cavity are small stiff hairs. These hairs called vibrissae act as sentinels. They filter out dust, minute insects and harmful micro-organisms including other foreign particles that flow in the air.
ANATOMY OF THE NOSE
Anatomically, the nose is broadly divided into two portions, viz., external and internal. The purview of the external section is limited. It refers to the centrally located projection portion slightly below the eyes.
THE NASAL PASSAGE
The nose commences the process of flowing air from the surroundings. The air is then transported our lungs. The air is brought within the body via the two nasal openings known as the right and left nasal passages. A flat membrane layer lines up the nasal passages. This lining is made up of thousands of epithelial cells.
Cilia & Epithelial cells: These epithelial cells are rather closely packed. These cells extend as fingerlike objects called cilia. These microscopic cilia line up the fringe of the nasal passages. The inhaled airborne particles are trapped by the cilia - the coarse hairs located inside the nostrils. These trapped particles are then captured by the mucous membrane that forms the lining of the nasal passages. The cilia keep on constantly waving. This creates a current of mucus. The current forces the particles downward. The particles then come downward via the pharynx and finally out through the nose.
Among the epithelial cells are the goblet cells.
Goblet cells & Capillaries: The goblet cells have a specialized function. The goblet cells produce mucus. This mucus is sticky, thick and moist. The cilia and the epithelial cells are coated by this mucus or fluid.
Near the nasal passages and just under the mucous membrane lie the capillaries. The capillaries are minute blood vessels.
NASAL PASSAGE FUNCTIONS
The nasal passages have two important roles. These functions are carried out while the air is transported from the nasal passages to the pharynx.
The filtration process: ages filter the air. Thus it segregates and debars those particles which may cause ailments. If these potentially dangerous elements like viruses and bacteria make their ways into the lungs, there may be infections of various types. The process also prevents dust particles and smog from clogging the smallest bronchioles. These bronchioles have very narrow air passages that need to be constantly kept clean and clear of dirt.
Preserving temperature & moisture: Second, the nasal passages keep the air warm besides maintaining the moistening effect. The warmth and moisture shields the respiratory system structures.
In the pharynx, the mucus is swallowed and passed to the stomach, where the particles are destroyed by stomach acid. If more particles are in the nasal passages than the cilia can handle, the particles build up on the mucus and irritate the membrane beneath it. This irritation triggers a reflex that produces a sneeze to get rid of the polluted air.
The nasal passages also moisten and warm air to prevent it from damaging the delicate membranes of the lung. The mucous membranes of the nasal passages release water vapor, which moistens the air as it passes over the membranes. As air moves over the extensive capillaries in the nasal passages, it is warmed by the blood in the capillaries. If the nose is blocked or "stuffy" due to a cold or allergies, a person is forced to breath through the mouth. This can be potentially harmful to the respiratory system membranes, since the mouth does not filter, warm, or moisten air.
NASAL FOSSAE
The internal portion of the human nose is divided into two cavities. These hollow portions are called nasal fossae. The nasal fossae open through the nostrils and end in a vertical slit on either side of the upper pharynx. The end portion is above the soft palate, and near the orifices of the Eustachian tubes. These Eustachian tube orifices lead to the tympanic cavity of the ear.
The two nasal cavities are vertically separated by a septum or a separation structure. The septum cartilage along with the perpendicular ethmoid plate and the vomer constitutes the partition wall between the right and left nasal fossae. Each of the nasal fossae is again sub-divided into three passages. They are called meatuses. The passages are delineated by turbinated or spongy bones. These boney borders start from the outer walls of the meatuses. These bones use narrow orifices to link with the different sinuses.
TYPES OF SINUSES
The sinuses are boney or tissue cavities in the skull. The sinuses connect the nostrils within the skull. The various sinuses are in the ethmoid, sphenoid, frontal, and superior maxillary bones. Inflammation of the sinus leads to the dysfunction called sinusitis.
NASAL FRAMEWORK
The nasal framework or the skeleton of the nose is formed of bones and cartilages. The bones constitute the top and sides of the nasal bridge. On both sides of the bridge are the cartilages. One is the upper lateral cartilage. The other is the lower lateral cartilage. Three to four other smaller cartilaginous plates known as the sesamoid cartilages are attached to the lower lateral cartilage.
DISEASES OF THE NOSE
NOSEBLEED: This common ailment is medically called epistaxis. Many factors can cause nosebleed. More often than not, nosebleeds take place due to minor irritation. Injury of the small septum veins (on the partition dividing the two nasal sides) can also lead to nosebleed. Rupture of these septum veins can occur spontaneously, or it may be caused by a cough or a sneeze. The sudden shock raises the blood pressure inside the nasal veins. This leads to the nosebleed.
Usually, nosebleeds stop in a short time. However, recurrent nosebleed may be signs of underlying serious diseases. Mention may be made of blood vessels diseases, certain cancers like leukemia, abnormally high blood pressure, infection, and nose tumors.
Treatment: The best way to stop persistent nosebleed is to apply pressure over the bleeding site. A cold compress can also help. The moment a person has nosebleed, he/she should immediately lift up his nose so that the blood flow direction is reversed. But if these remedies fail to yield the desired results, seek immediate advice from a doctor. Recurrent or severe nosebleeds do need urgent medical attention.
RHINITIS: This is an inflammatory disorder. Rhinitis affects the nasal mucous membrane called the nasal catarrh. The common symptoms of rhinitis are watery discharge from the nose. It can also be accompanied by nasal congestion. There can be breathing problems as well. Many rhinitis cases are caused by the common cold. Other factors can be other diseases, certain medications, irritation from pollutants and other elements, and nasal allergies.
Treatment: Generally, nasal decongestants shrink and dry up the swollen mucous membranes. Local use of nasal sprays and drops can also help. Breathing of menthol put in a cup of lukewarm water also helps to relieve congestion. However, excessive use of any of these treatments can dry up the membranes. They can even damage the sensitive nasal membranes. Allergic rhinitis is treated with antihistamines.
HAY FEVER: AS hay fever occurs in the same season it is identified as a seasonal rhinitis. Hay fever is caused by allergy to pollens. The hay fever symptoms are wheezing, nose and eye membrane inflammation, and acute sneezing seizures. Family sensitiveness to hay fever can be a cause of the hay fever symptoms in any individual. Studies have shown that about 10 American citizens are prone to hay fever symptoms.
Treatment: Physicians treat hay fever by determining the sensitizing agent(s). The patient's skin is first scratched and various pollens applied. A wheal-and-flare reaction is produced by the pollen to which the patient is allergic. The hay fever syndrome is activated when the body releases histamine as a counter to the antigen-antibody reaction. This release of the histamine irritates the glands and the blood vessels. Notably a few of the anti-histaminic agents can provide relief. A series of pollen extracts injections as a preventive measure prior to the advent of the pollen producing season has delivered positive results. This is a long-term therapy.
COMMON COLD: This acute infectious disease is caused by more than 100 different types of viruses. Common cold affects the mucous membrane of the upper respiratory tract. The symptoms of common cold are coughing, sore throat, nasal discharge and nasal congestion. Many of these bacteria-caused symptoms are similar to the allergic nasal conditions arising from asthma hay fever. Hence, it is not very easy to diagnose common cold.
Common cold can be accompanied by fever as well. It has been seen that common cold conditions subside within a week's time. However, complications may arise from severe common cold. This can lead to many diseases like middle-ear infections or sinus, pneumonia and bronchitis.
Different viruses have various strains and therefore degrees of virulence. Hence if a patient takes medication for a particular virus or a strain or a degree of attack, that medication may not be affective with respect to another virus. The same strain of the virus but with a different degree of virulence can again strike. So it is not uncommon to find that even after one has taken a full dose of a medication, that person again gets down with another bout of common cold.
Earlier beliefs: In the olden times, the common belief was that exposure to cold conditions caused common cold. This feeling was partly buttressed by the fact that during such a drab weather condition the people used to huddle together. The result was that common cold conditions easily spread from one another. Another school of thought pinpointed chilling as a cause of common cold. It extended the infections that were consequent upon the chilling effect as the reason. However, studies have proved that the chilling effect can be one of the causes, though not the main cause.
In the 1950s, antihistamine medications were prescribed as the treatment if the common cold was detected at the initial stages. Now the consensus among the physicians is that these drugs do not address the progression of the ailment or neutralize the virus producing the symptoms.
Nobel laureate and American chemist Linus Pauling came up with the proposition that Vitamin C doses in large quantities shorten the cold duration. He further stated that the vitamin alleviates the symptoms. However, follow-up researches have proved that this contention is untrue.
3-dimensional picture of the common cold virus: Way back in 1985, American medical scientists were successful in bringing out a three-dimensional model of a common cold producing virus. That scale was in the atomic scale. The atomic scale model in the three dimensional format of the virus causing common cold created a sensation. The scientists utilized the advanced techniques of X-ray crystallography.
The studies were concentrated on the viral coat. It specifically took up the coat sites that was antibody binding. They showed a rather high degree of variability. This was particularly true with respect to the antigenic factor. Further researches on the findings demonstrated it is impossible to formulate that a panacea for all common colds.
Modern methods to treat common cold: The modern-day techniques are concentrated on addressing or relieving the patients of the common cold symptoms. This method is given a backup by a medication move to prevention recurrence of the complications. To avoid complications the patients are advised bed rest. Even when the cold is not so severe, bed rest helps because the general constitution of the patient remains weak. Moreover, if the patient remains in bed, the chances are dim of the contagious disease attacking others. More often than not, as a preventive move, antibiotics are administered. But no direct connection has yet been found between the antibiotics and its effects on the common cold causing virus.
Interestingly enough, common cold has been found to be the major cause of absenteeism in educational institutions and industries.
INFLUENZA: This is an infectious and a contagious ailment. It is commonly termed as flu and also grippe. Influenza is usually acute. Influenza especially attacks the trachea, an important part of the respiratory tract. A simple influenza bout is accompanied by several symptoms. They can be eye burning, sore throat, dry cough or even discharges from the nose or nasal obstruction. The symptoms disappear and the body temperature resumes the normal level in such simple influenza instances.
Nose: The Starting Point Of Life-Sustaining Process MEMBRANE
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