2,3-Diphosphoglycerate: A compound in red blood cells that affects oxygen binding to and release from hemoglobin.
Ablation: Destruction of part or all of an organ or structure.
Abscess: Purulent collection of fluid separated from surrounding tissue by a wall consisting of inflammatory cells and adjacent organs.
Acanthosis nigricans: Increased thickness and hyperpigmentation of the outer cell layers of the skin; typically observed at areas of flexure.
Acaricide: A chemical that kills mites and ticks.
Acetylcholine: Neurotransmitter at synapses in the ganglia of the visceral motor system and a variety of sites within the central nervous system.
Achalasia: Disorder in which the esophageal sphincter is impaired, preventing normal swallowing and often causing reflux of contents and a feeling that something is caught in the throat.
Achlorhydria: Absence of free hydrochloric acid in the stomach.
Acinar cells: Cells in the pancreas responsible for the synthesis, secretion, and storage of certain digestive enzymes.
Action potential: A rapid change in the polarity of the voltage of a cell membrane from negative to positive and back to negative; a wave of electrical discharge that travels across a cell membrane.
Acute coronary syndromes: Ischemic chest discomfort at rest most often accompanied by ST-segment elevation, ST-segment depression, or T-wave inversion on the 12-lead electrocardiogram; caused by plaque rupture and partial or complete occlusion of the coronary artery by thrombus. Acute coronary syndromes include myocardial infarction and unstable angina.
Acute respiratory distress syndrome: Diffuse inflammatory condition of the lung resulting in damage of alveoli, surfactant production, innate immune system response, and dysregulation of hemostasis in the pulmonary tract.
Addiction: A primary, chronic, neurobiologic disease, with genetic, psychosocial, and environmental factors influencing its development and manifestations. Characterized by behaviors such as impaired control over substance use, compulsive use, continued use despite harm, and craving.
Adenoma: A non-malignant tumor of the epithelial tissue that is characterized by glandular structures.
Adenomatous polyposis coli: A gene associated with familial adenomatous polyposis, an inherited disorder characterized by the development of myriad polyps in the colon, often occurring in adolescents and young adults ages 15 to 25.
Adjuvant chemotherapy: Treatment given after primary surgical treatment and designed to eliminate any remaining cancer cells that are undetectable, with the goal of improving survival.
Adrenalectomy: Surgical removal of an adrenal gland.
Adverse drug reaction: Any unexpected, unintended, undesired, or excessive response to a medication that requires discontinuing the medication; requires changing the medication; requires modifying the dose (except for minor dosage adjustments); necessitates admission to the hospital; prolongs stay in a health care facility; necessitates supportive treatment; significantly complicates diagnosis; negatively affects prognosis; or results in temporary or permanent harm, disability, or death.
Aeroallergen: Airborne substance that causes an ...