Google
Yahoo
Msn
Ebay
Wikipedia
National Institutes of Health
Health and Medical Information
American Heart Association
Healthfinder
Parenthood
Ask Alice
WebMD
Nose - Introduction
Nose, organ of smell, and also part of the apparatus of respiration and voice. Considered anatomically, it may be divided into an external portion—the visible projection portion, to which the term nose is popularly restricted—and an internal portion, consisting of two principal cavities, or nasal fossae, separated from each other by a vertical septum, and subdivided by spongy or turbinated bones that project from the outer wall into three passages, or meatuses, with which various sinuses in the ethmoid, sphenoid, frontal, and superior maxillary bones communicate by narrow apertures.
The uppermost portion of the human respiratory system, the nose is a hollow air passage that functions in breathing and in the sense of smell. The nasal cavity moistens and warms incoming air, while small hairs and mucous filter out harmful particles and microorganisms. This illustration depicts the interior of the human nose.
The margins of the nostrils are usually lined with a number of stiff hairs (vibrissae) that project across the openings and serve to arrest the passage of foreign substances, such as dust and small insects, which might otherwise be drawn up with the current of air intended for respiration. The skeleton, or framework, of the nose is partly composed of the bones forming the top and sides of the bridge, and partly of cartilages. On either side are an upper lateral and a lower lateral cartilage, to the latter of which are attached three or four small cartilaginous plates, termed sesamoid cartilages. The cartilage of the septum separates the nostrils and, in association posteriorly with the perpendicular plate of the ethmoid and with the vomer, forms a complete partition between the right and left nasal fossae.
The nasal fossae, which constitute the internal part of the nose, are lofty and of considerable depth. They open in front through the nostrils and behind end in a vertical slit on either side of the upper pharynx, above the soft palate, and near the orifices of the Eustachian tubes, leading to the tympanic cavity of the ear.
In the olfactory region of the nose the mucous membrane is very thick and colored by a brown pigment. The olfactory nerve, or nerve of smell, terminates in the nasal cavity in several small branches; these ramify in the soft mucous membrane and end in tiny varicose fibers that in turn terminate in elongated epithelial cells projecting into the free surface of the nose.
World Health Organization
Human Disease
Human Disease, in medicine, any harmful change that interferes with the normal appearance, structure, or function of the body or any of its parts. Since time immemorial, disease has played a role in the history of societies. It has affected—and been affected by—economic conditions, wars, and natural disasters. Indeed, the impact of disease can be far greater than better-known calamities. An epidemic of influenza that swept the globe in 1918 killed between 20 million and 40 million people. Within a few months, more than 500,000 Americans died—more than were killed during World War I (1914-1918), World War II (1939-1945), the Korean War (1950-1953), and the Vietnam War (1959-1975) combined.
Diseases have diverse causes, which can be classified into two broad groups: infectious and noninfectious. Infectious diseases can spread from...
Drug, substance that affects the function of living cells, used in medicine to diagnose, cure, prevent the occurrence of diseases and disorders, and prolong the life of patients with incurable conditions.
Since 1900 the availability of new and more effective drugs such as antibiotics, which fight bacterial infections, and vaccines, which prevent diseases caused by bacteria and viruses, has increased the average American’s life span from about 60 years to about 75 years. Drugs have vastly improved the quality of life. Today, drugs have contributed to the eradication of once widespread and sometimes fatal diseases such as poliomyelitis and smallpox.
