Porth's Essentials of Pathophysiology, 4e

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Glossary

Dermatome  The area of the skin supplied with afferent nerve fibers of a single dorsal root of a spinal nerve. Desmosome  A small, circular, dense area within the intercellular bridge that forms the site of adhesion between intermediate filaments and cell membranes. Desquamation  A normal process in which the cornified layer of the epidermis is shed in fine scales or sheets. Dialysis  The process of separating colloids and crystal- line substances in solution, which involves the two distinct physical processes of diffusion and ultrafil- tration; or a medical procedure for the removal of urea and other elements from the blood or lymph. Diapedesis  The outward passage of red or white blood corpuscles through the intact walls of the vessels. Diaphoresis  Perspiration, especially the profuse perspi- ration associated with elevated body temperature, physical exertion, exposure to heat, and mental or emotional stress. Diarthrosis  A specialized articulation that permits, to some extent, free joint movement. (Adjective: diarthrodial) Diastole  The dilatation of the heart; or the period of dilatation, which is the interval between the second and the first heart sound and is the time during which blood enters the relaxed chambers of the heart from the systemic circulation and the lungs. Differentiation  The act or process in development in which unspecialized cells or tissues acquire more spe- cialized characteristics, including those of physical form, physiologic function, and chemical properties. Diffusion  The process of becoming widely spread, as in the spontaneous movement of molecules or other particles in solution from an area of higher concen- tration to an area of lower concentration, resulting in an even distribution of the particles in the fluid. Dimer  A compound or unit formed by the combination of two identical molecules or radicals of a simpler compound. (Adjective: dimeric) Diopter  A unit of measurement of the refractive power of lenses equal to the reciprocal of the focal length in meters. Diploid  Pertaining to an individual, organism, strain, or cell that has two full sets of homologous chromosomes. Disseminate  To scatter or distribute over a consider- able area. Distal  Away from or being the farthest from a point of reference. Diurnal  Of, relating to, or occurring in the daytime. Diverticulum  A pouch or sac of variable size occurring naturally or through herniation of the muscular wall of a tubular organ. Dorsum  The back or posterior. (Adjective: dorsal) Dysgenesis  Defective or abnormal development of an organ or part, typically occurring during embryonic development. (Also called dysgenesia.) Dyslexia  A disturbance in the ability to read, spell, and write words. Dyspepsia  The impairment of the power or function of digestion, especially epigastric discomfort following eating.

Dysphagia  A difficulty in swallowing. Dysphonia  Any impairment of the voice that is experi- enced as difficulty in speaking. Dysplasia  The alteration in size, shape, and organization of adult cell types. Eburnation  The conversion of bone or cartilage, through thinning or loss, into a hard and dense mass with a worn, polished, ivorylike surface. Ecchymosis  A small hemorrhagic spot, larger than a pete- chia, in the skin or mucous membrane caused by the extravasation of blood into the subcutaneous tissues. Ectoderm  The outermost of the three primary germ layers of the embryo, and from which the epidermis and epidermal tissues, such as nails, hair, and glands of the skin, develop. Ectopic  Relating to or characterized by an object or organ being situated in an unusual place, away from its normal location. Edema  The presence of an abnormal accumulation of fluid in interstitial spaces of tissues. (Adjective: edematous) Efferent  Conveyed or directed away from a center. Effusion  The escape of fluid from blood vessels into a part or tissue, as an exudation or a transudation. Embolus  A mass of clotted blood or other formed ele- ments, such as bubbles of air, calcium fragments, or a bit of tissue or tumor, that circulates in the blood- stream until it becomes lodged in a vessel, obstruct- ing the circulation. (Plural: emboli) Empyema  An accumulation of pus in a cavity of the body, especially the pleural space. Emulsify  To disperse one liquid throughout the body of another liquid, making a colloidal suspension, or emulsion. Endocytosis  The uptake or incorporation of substances into a cell by invagination of its plasma membrane, as in the processes of phagocytosis and pinocytosis. Endoderm  The innermost of the three primary germ lay- ers of the embryo, and from which epithelium arises. Endogenous  Growing within the body; or developing or originating from within the body or produced from internal causes. Endoscopy  The visualization of any cavity of the body with an endoscope. Enteral  Within or pertaining to the intestine. Enteropathic  Relating to any disease of the intestinal tract. Enzyme  A protein molecule produced by living cells that catalyzes chemical reactions of other organic substances without itself being destroyed or altered. Epiphysis  The expanded articular end of a long bone (head) that is separated from the shaft of the bone by the epiphyseal plate until the bone stops growing, the plate is obliterated, and the shaft and the head become united. Epithelium  The covering of the internal and external surfaces of the body, including the lining of vessels and other small cavities. Epitope  The simplest form of an antigenic determinant that combines with an antibody or a T-cell receptor to cause a specific reaction by an immunoglobulin.