smallpox vaccine A vaccine that contains a live virus called vaccinia that is used to prevent smallpox. The vaccine does not contain the variola virus that causes smallpox, but exposes the immune system to proteins that look like the virus so that an immune response occurs. Through the use of the vaccine, smallpox was eliminated…
smear, Pap See Pap test.
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…
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…
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…
skeletal Pertaining to the skeleton, the bones of the body that collectively provide the frame for the body.
skeletal dysplasia One of a large contingent of genetic diseases in which the bony skeleton forms abnormally during fetal development. Achondroplasia is one form of skeletal dysplasia.
skeletal muscle Along with smooth and cardiac muscle, one of the types of muscle tissue in the body. Skeletal muscle represents the majority of muscle tissue. It is the type of muscle that powers movement of the skeleton, as in walking and lifting.
skeleton The framework of the body, which is composed of 206 bones. See also bones of the arm, wrist, and hand; bones of the head; bones of the leg, ankle, and foot; bones of the trunk.
skin The body’s outer covering, which protects against heat and light, injury, and infection. Skin regulates body temperature and stores water, fat, and vitamin D. The skin, which weighs about 6 pounds, is the body’s largest organ. It is made up of two main layers: the epidermis and the dermis. The outer layer of the…
skin, scalded, syndrome See staphylococcal scalded skin syndrome.
skin biopsy Removal of a piece of skin for the purpose of diagnostic examination. Skin biopsy is most frequently done to diagnose skin growths, such as moles, or skin conditions, such as rashes. Different skin biopsy techniques are used in different situations. A shave biopsy takes a thin slice and can be used to remove…