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.
Acanthosis nigricans: Dark patches of skin with a thick, velvety texture; increased thickness and hyperpigmentation of the outer cell layers of the skin; typically observed at areas of flexure. Most commonly found in those who are overweight, have darker skin, and/or have diabetes or prediabetic conditions.
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: The 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 interstitial nephritis: An acute inflammation of the kidney, often due to drugs; patients commonly present with fever, rash, and peripheral eosinophilia.
Acute rheumatic fever: Post-streptococcal immune sequelae occurring 2 to 3 weeks following inadequately treated throat infection with group A Streptococcus.
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 nonmalignant 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.
Adjuvant therapy: Treatment that follows a definitive local therapy, usually surgery, to eradicate undetectable tumor cells and follows the primary modality with the intent of reducing the risk of disease relapse and prolonging survival. The ultimate goal is to cure patients who would not otherwise be cured by the primary modality alone.
Adrenalectomy: Surgical removal of an adrenal gland.
Adverse drug reaction: As defined by the American Society of Health-System Pharmacists, any unexpected, unintended, undesired, or excessive response to a medication that requires discontinuing the medication; changing the medication; modifying the dose (except for minor dosage adjustments); necessitates admission to the hospital; prolongs stay in a healthcare ...