sodium The major positive ion (cation) in the fluid surrounding cells in the body. The chemical notation for sodium is Na+. When sodium is combined with chloride, the resulting substance is a crystal called table salt. Excess dietary sodium is largely excreted in the urine, but too much salt in the diet tends to increase…
socialized medicine A medical system like that of a socialist country, in which medical facilities and payments are under government, rather than private, control. Most industrialized nations, including the US, have medical systems under some combination of state and private control. For examples, socialized medicine is practiced in Canada and Britain.
socialization The learning process a child goes through as he or she learns how to interact appropriately with other people.
social worker A health professional who assists individuals and families with social or emotional issues. Within the medical system, a social worker might help uninsured families who need medical care find help; work with grieving parents, spouses, or other family members; provide individual therapy; or help patients find resources to meet their needs for personal…
social phobia A paralyzing fear of interacting with others. Symptoms include excessive blushing, sweating, trembling, rapid heartbeat, muscle tension, nausea, and extreme anxiety. Social phobia can occur in very young children or emerge at a later age. It can be disabling to a person’s work and social and family relationships. Many people with social phobia…
snoring A sound created by vibrations of the uvula and soft palate during sleep. During normal breathing, air passing through the throat en route to the lungs travels by the tongue, soft palate, uvula, and tonsils. When a person is awake, the muscles in the back of the throat tighten to hold these structures in…
Snellen chart See chart, Snellen.
snakebite The bite of a snake, whether poisonous or not. Most snakes are not poisonous, but their bites can nonetheless cause painful puncture wounds that require treatment. If a snakebite victim knows a snake was poisonous, or if the person did not see or recognize the snake, he or she should immediately seek emergency treatment….
snake stick See Aesculapius.
smooth muscle Along with skeletal and cardiac muscle, one of the types of muscle tissue in the body. Smooth muscle generally forms the supporting tissue of blood vessels and hollow internal organs, such as the stomach, intestine, and bladder. It is considered smooth because it does not have the microscopic lines (the striations) seen in…
Smoldering leukemia is a form of chronic leukemia characterized by a slow, indolent course with minimal symptoms and gradual progression. It is often diagnosed incidentally during laboratory tests when an increased number of atypical leukocytes are found in the blood without pronounced clinical symptoms. This type of leukemia can persist for years without significant deterioration…
smell The sense that provides information about an object’s scent, often giving clues to the palatability of food, the safety of air, and other matters. The organs of smell are made up of patches of tissue called the olfactory membranes that are each about the size of a postage stamp. These membranes are located in…