Porth's Essentials of Pathophysiology, 4e

G l o s s a r y

Abduction  The act of abducting (moving or spreading away from a position near the midline of the body or the axial line of a limb) or the state of being abducted. Abrasion  The wearing or scraping away of a substance or structure, such as the skin, through an unusual or abnormal mechanical process. Abscess  A collection of pus that is restricted to a specific area in tissues, organs, or confined spaces. Accommodation  The adjustment of the lens (eye) to variations in distance. Acromion  The lateral extension of the spine of the scapula, forming the highest point of the shoulder. (Adjective: acromial) Acuity  The clearness or sharpness of perception, espe- cially of vision. Adaptation  The adjustment of an organism to its physical or psychological environment, through changes and responses to stress of any kind. Adduction  The act of adducting (moving or drawing toward a position near the midline of the body or the axial line of a limb) or the state of being adducted. Adhesin  The molecular components of the bacterial cell wall that are involved in the adhesion processes. Adrenergic  Activated by or characteristic of the sym- pathetic nervous system or its neurotransmitters (i.e., epinephrine and norepinephrine). Aerobic  Growing, living, or occurring only in the pres- ence of air or oxygen. Afferent  Bearing or conducting inward or toward a center, as an afferent neuron. Agglutination  The clumping together of particles, microorganisms, or blood cells in response to an antigen–antibody reaction. Agonist  A muscle whose action is opposed by another muscle (antagonist) with which it is paired or a drug or other chemical substance that has affinity for or stimulates a predictable physiologic function. Akinesia  An abnormal state in which there is an absence or poverty of movement. Allele  One of two or more different forms of a gene that can occupy a particular locus on a chromosome. Alveolus  A small saclike structure, as in the alveolus of the lung. Ambient  The surrounding, encompassing, or prevailing area or environment; especially of or pertaining to the area immediately around the body. Amblyopia  A condition of vision impairment without a detectable organic lesion of the eye. Amine  An organic compound containing nitrogen. Amorphous  Without a definite form; shapeless. Amphoteric  Capable of reacting chemically as an acid or a base. Ampulla  A saclike dilatation of a duct, canal, or any other tubular structure.

Anabolism  A constructive metabolic process charac- terized by the conversion of simple substances into larger, complex molecules. Anaerobic  Growing, living, or occurring only in the absence of air or oxygen. Analog  A part, organ, or chemical having the same function or appearance but differing in respect to a certain component, such as origin or development. Anaplasia  A change in the structure of cells and in their orientation to each other that is characterized by a loss of cell differentiation, as in cancerous cell growth. Anastomosis  The connection or joining between two vessels; or an opening created by surgical, traumatic, or pathologic means. Androgen  Any substance, such as a male sex hormone, that increases male characteristics. Anergy  A state of absent or diminished reaction to an antigen or group of antigens. Aneuploidy  A variation in the number of chromo- somes within a cell involving one or more missing chromosomes rather than entire sets. Aneurysm  An outpouching or dilation in the wall of a blood vessel or the heart. Ankylosis  Stiffness or fixation of separate bones of a joint, resulting from disease, injury, or surgical procedure. (Verb: ankylose) Anorexia  Lack or loss of appetite for food. (Adjective: anorexic) Anoxia  An abnormal condition characterized by the total lack of oxygen. Antagonist  A muscle whose action directly opposes that of another muscle (agonist) with which it is paired, or a drug or other chemical substance that can diminish or nullify the action of a neuromediator or body function. Anterior  Pertaining to a surface or part that is situated near or toward the front. Antigen  A substance that generates an immune response by causing the formation of an antibody or reacting with antibodies or T-cell receptors. Apex  The uppermost point, the narrowed or pointed end, or the highest point of a structure, such as an organ. Aphagia  A condition characterized by the refusal or the loss of ability to swallow. Aplasia  The absence of an organ or tissue due to a developmental failure. Apnea  The absence of spontaneous respiration. Apoptosis  A mechanism of programmed cell death, marked by shrinkage of the cell, condensation of chromatin, formation of cytoplasmic blebs, and fragmentation of the cell into membrane-bound bodies eliminated by phagocytosis. Apraxia  Loss of the ability to carry out familiar, pur- poseful acts or to manipulate objects in the absence of paralysis or other motor or sensory impairment.

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