sleep apnea Temporary stoppage of breathing during sleep, often resulting in daytime sleepiness. Treatment depends on the type of sleep apnea present. Sleep apnea is classified as obstructive or central. Sleep apnea that is associated with air passage obstruction may require losing excessive weight, avoiding alcohol and sedatives, sleeping on one side, medications to relieve…
sleep, rapid eye movement See REM sleep.
sleep, non-rapid eye movement See NREM sleep.
sleep The body’s rest cycle. Sleep is triggered by a complex group of hormones that respond to cues from the body itself and the environment. About 80 percent of sleep is dreamless and is known as nonrapid eye movement (NREM) sleep. During NREM sleep, the breathing and heart rate are slow and regular, the blood…
SLE Systemic lupus erythematosis. See lupus erythematosis, systemic.
skull A collection of bones that encase the brain and give form to the head and face. These bones include the frontal, parietal, occipital, temporal, sphenoid, ethmoid, zygomatic, maxilla, nasal, vomer, palatine, inferior concha, and mandible. See also bones of the head.
skin test for immunity A method of evaluating whether a person has developed an immune response to a certain infection. A substance is injected into the deep layer of the skin (dermis) and causes a reaction if the immune system recognizes it. One of the most common skin tests is the tuberculin test, which reveals…
skin tag A small tag of skin that may be squat (sessile) or on a stalk (a peduncle). Skin tags commonly occur on the eyelids, neck, armpits, upper chest, and groin. This tiny benign tumor of the skin usually causes no symptoms unless it is repeatedly irritated as, for example, by a collar. Treatment may…
skin graft, split-thickness A graft technique in which sheets of skin containing the epidermis and part of the dermis are used. This graft might be used when only portions of the skin have been injured, such as after a scraping injury.
skin graft, porcine A skin graft in which pig skin is used. Like grafts from human donors, porcine grafts are usually just a short-term protective measure.
skin graft, pinch A graft technique in which very small squares of skin are attached to the area that needs to be covered, in hopes that they will start to grow and cover the area.
skin graft, pedicle A graft technique in which a piece of skin from a nearby area remains attached at one of its corners, while the main part of the piece is reattached over the area that needs to be covered.