Y chromosome The sex chromosome that is found, together with an X chromosome, in most normal males. The Y chromosome contains the unique male-determining gene and the male fitness genes that are active only in the testis and are responsible for the formation of sperm. Other genes on the Y chromosome have counterparts on the…
Y chromosome sex-determining region The region on the Y chromosome that decides the sex of the individual. Abbreviated SRY. SRY is necessary for male determination. It encodes the testis-determining factor. Mutations in SRY are responsible for XY females with gonadal dysgenesis who appear to be normal females at birth but at puberty do not develop…
Y map The array of genes on the Y chromosome.
yard A measurement of length that is equal to 0.9 meters, 3 feet, or 36 inches.
yawn Involuntary opening of the mouth, accompanied by slowly breathing inward and then outward. Repeated yawning can be a sign of drowsiness, boredom, or depression. The yawn helps to open tiny air sacs (alveoli) in the lungs that can collapse during shallow breathing.
yaws A chronic infectious disease that occurs commonly in the warm, humid regions of the tropics. Yaws is characterized by bumps on the skin of the face, hands, feet, and genital area. Almost all cases of yaws are in children under 15 years of age. The organism that causes yaws is a type of spirochete…
yeast A group of single-celled fungi that reproduce by budding. Most yeast is harmless, and yeast is commonly present without ill effect on normal human skin and mucous membranes, including the gastrointestinal (GI) tract. In the GI tract, the amount of yeast is usually controlled by helpful bacteria, although this balance can be upset by…
yeast diaper rash Infection in the diaper area of a baby that is caused by a yeast called Candida. Certain conditions, such as antibiotic use or excessive moisture, can upset the balance of microbes and allow an overgrowth of Candida. The infected skin is usually fiery red with areas that may have a raised red…
yeast infection Overgrowth of yeast that affects the skin (yeast rash), mouth (thrush), digestive tract, esophagus, vagina (vaginitis), or other parts of the body. Yeast infections occur most frequently in moist areas of the body. Although Candida albicans and other Candida yeasts are the most frequent offenders, other yeast groups are known to cause illness,…
yeast rash A slightly raised pink-to-red rash that is caused by proliferation of yeast, usually in a moist area such as the groin. Yeast rash is most common in infants, but it can also occur on the skin of older children and adults. Treatment involves keeping the affected area clean and dry and applying topical…
yeast vaginitis Infection of the vagina by Candida albicans, which characteristically causes itching, burning, soreness, pain during intercourse and urination, and vaginal discharge. Yeast vaginitis occurs when new yeast are introduced into the vagina or when the quantity of yeast in the vagina increases relative to the quantity of bacteria. Yeast vaginitis can be exacerbated…
yeast vulvitis A yeast infection of the vulva. Yeast vulvitis commonly occurs with yeast vaginitis. Common symptoms include itching, burning, soreness, pain during intercourse and urination, and vaginal discharge. Treatment involves use of topical or oral antifungal medications. See also Candida albicans; yeast; yeast infection; yeast vaginitis.