Asthma Fev1 Common Cold

The cold-prone human respiratory tract, the main area of asthma fev1 common cold is about 16 inches long in the average adult, made up of bones, muscles and cartilage and packed with glands, tubes, folds and flaps. Yet inhaled air takes
less than two thirds of a second to travel the entire route.

The journey starts in an antechamber, the nose, where the air swirls for a quarter second or so, Special cells in the nasal cavity provide the sense of smell; tiny openings link the cavity to air-filled spaces in the skull called sinuses. Other openings link the nose to the eyes through the nasolacrimal ducts and to the ears through the Eustachian tubes.

From the nose, in a leg of its trip that lasts less than 1/10 second, air flows swiftly through the pharynx, or throat, and down into the larynx, or voice box.
In the larynx a set of vibrating flaps, the vocal cords, turns a rush of air io sound, and a valve prevents food and liquid from entering the airway. The last stage of the trip is the slowest—a third of a second. The air goes down the trachea (windpipe) to tubes called bronchi and fans out into the lungs. There the breath— warmed or cooled, moistened, and cleansed of particles carrying bacteria and viruses— fulfills the purpose of the entire system: The air gives up oxygen to feed the body, and takes on carbon dioxide for the return trip.

The linked airways of the respiratory tract begin at the nose and mouth. Beyond lies the pharynx's, studded with clumps of protective tissue called tonsils and adenoids. At the larynx food is diverted to the stomach and air is directed through the trachea to the bronchi, which branch off into the lungs..

Safeguards of the upper airway
Every day an average adult breathes in and out about 22,000 times, inhaling and exhaling some 500 cubic feet of air. Along with essential oxygen come dirt, pollen and disease germs—and, over part of the breathing route, food. The upper airway (opposite), which conducts this enormous volume of air from the nose to the windpipe, is designed to remove, divert or neutralize these contaminants and simultaneously adjust air temperature and humidity to internal requirements which is perfect for asthma fev1 common cold.

The nose provides the first line of defense against airborne threats. Short, thick hairs just inside the nostrils filter out the larger particles. Most of the smaller particles are trapped—stuck like flies on flypaper—by the mucous membrane, which lines the nasal cavity and most of the airway down into the lungs.

This protective lining, the part of the system most affected by a cold, is covered with invisibly small hairs, or cilia—as many as 250 to one membrane cell. They are continuously blanketed by mucus, the viscous secretion of the glands within the membrane.

Inside the nose, the area that incoming air must pass over is increased by projections called turbinates, scroll-like bones sticking into the passageway from the side. They not only present more mucus for more effective trapping of dirt but also increase the contact between the air and the membrane’s network of blood vessels, which warm or cool the air.

Incoming air reaching the pharynx must be separated from food, which also moves through this part of the passageway. This tricky operation often goes awry, producing fits of coughing when food goes down the wrong way. Protecting the airway from food is the job of the epiglottis, a one-way valve that moves during a swallow to close off the larynx and shunt food into the esophagus, on its way to the stomach below. This is a key factor of asthma fev1 common cold..

Twitter About The Common Cold Cure