A-H 1

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

A purulent collection of fluid separated from surrounding tissue by a wall consisting of inflammatory cells and adjacent organs. It usually contains necrotic debris, bacteria, and inflammatory cells.

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 syndrome

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. It include myocardial infarction and unstable angina.

Acute kidney injury

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.

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. It is characterized by behaviors that include one or more of the following: 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.

APC Adenomatous polyposis coli

A gene associated with familial adenomatous polyposis (FAP), 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 the primary surgical treatment and designed to eliminate any remaining cancer cells that are undetectable, with the goal of improving survival.

Adjuvant therapy

Treatment which 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.

ADR Adverse drug reactionn

Any unexpected, unintended, undesired, or excessive response to a medication that requires discontinuing or changing the medication, or modifying the dose (except for minor dosage modifcations). May necessitate hospital admission and/or supportive treatment; prolong stay in a health care facility; significantly complicate diagnosis; negatively affect prognosis; or result in temporary or permanent harm, disability, or death.

Aeroallergen

An airborne substance that causes an allergic response.

Afteroload

The force against which a ventricle contracts that is contributed to by the vascular resistance, especially of the arteries, and by the physical characteristics (mass and viscosity) of the blood.

Ageism

Discrimination against aged persons.

Air embolus

An obstruction in a small blood vessel caused by air that is introduced into a blood vessel and is carried through the circulation until it lodges in a smaller vessel.

Akathisia

Motor or subjective feelings of restlessness, often characterized by the urge to move limbs and inability to sit still.

Akinesia

Lack of movement.

Allodynia

Pain that results from a stimulus that does not normally cause pain.

Allogeneic hematopoietic stem cell transplant

A transplant taking cells from one person and donating them to another.

Allogeneic

A transplant taking cells from one person and donating them to another.

Allograft

Tissue or organ transplanted from a donor of the same species but different genetic makeup; recipient’s immune system must be suppressed to prevent rejection of the graft.

Allograft survival

After the transplant procedure, the transplanted organ continues to have some degree of function, from excellent to poor.

Allorecognition

Recognition of the foreign antigens present on the transplant organ or the donor’s antigen presenting cells.

Alopecia

Hair loss.

Ambulatory esophageal reflux monitoring

A telemetry capsule containing a tiny camera is swallowed, or a transnasal catheter is inserted to determine how often reflux is occurring as well as the incidence of abnormal esophageal acid exposure. The telemetry capsule provides about 48 hours of data, whereas the transnasal catheter provides about 24 hours of data.

Amenorrhea

Abnormal cessation or absence of menses.

Ampulla of vater

Dilation of the duodenal wall at the opening of the fused pancreatic and common bile ducts.

Amylin

A 37-amino acid polypeptide hormone that is secreted from the β cells of the pancreas in response to nutrients. Mechanisms of action include slowing gastric emptying, suppressing postmeal glucagon secretion, and suppressing appetite.

Amyloid

Any of a group of chemically diverse proteins that are composed of linear non-branching aggregated fibrils.

Anaerobic

Living in the absence of oxygen.

Anaphylactic/anaphylaxis

Immediate, severe, potentially fatal hypersensitivity reaction induced by an antigen.

Anaphylactoid

An anaphylactic-like reaction, similar in signs and symptoms but not mediated by IgE. The drug causing this reaction produces direct release of inflammatory mediators by a pharmacological effect.

Anastomosis

The connection of two hollow organs to restore continuity after resection.

Anergy

A reduction or lack of an immune response to a specific antigen.

Aneurysm

A blood-filled bulge which forms in the wall of a weakened blood vessel; if ruptured, may result in bleeding, shock, and/or other negative health outcome including mortality.

Angioedema

Swelling similar to urticaria (hives), but the swelling occurs beneath the skin instead of on the surface. Characterized by deep swelling around the eyes and lips and sometimes of the hands and feet. If it proceeds rapidly, it can lead to airway obstruction and suffocation, and should therefore be treated as a medical emergency

Angiogenesis

The formation of new blood vessels. Increased blood flow to deliver nutrients is required for tumor growth

Angiography

Examination of the blood vessels using x-rays after injection of a radiopaque substance.

Anosmia

Loss of smell.

Anterior circulation

Blood supply to the anterior section of the brain supplied by the internal carotid arteries, anterior cerebral artery, and middle cerebral artery.

Anterograde amnesia

Inability to create new memories or recall past events

Anticoagulant

Any substance that inhibits, suppresses, or delays the formation of blood clots. These substances occur naturally and regulate the clotting cascade. Several anticoagulants have been identified in a variety of animal tissues and have been commercially developed for medicinal use.

Antiprotease

A substance that inhibits the enzymatic activity of a protease.

Aortic stenosis

A condition in which the aortic valve becomes thickened or calcified leading to a narrowing of the aortic valve opening and restriction of blood flow from the left ventricle.

Aphakic

The absence of a lens in the eye.

Aphasia

Impairment of language affecting the ability to speak and to understand speech.

Aphthous ulcer

A small superficial area of ulceration within the gastrointestinal mucosa, typically found in the oral cavity.

Apoptosis

Programmed cell death as signaled by the nuclei in normally functioning cells when age or state of cell health and condition dictates.

Arcuate scotoma

An arc-shaped area of blindness in the field of vision.

Arteriovenous malformation

A tangle of blood vessels, usually in the brain, that results in abnormal connections between arteries and veins; if ruptured, may result in hemorrhage.

Arthrocentesis

Puncture and aspiration of a joint. Certain drugs can be injected into the joint space for a local effect.

Articular

Related to a joint or joints.

Ascites

Accumulation of fluid within the peritoneal cavity.

Asterixis

Involuntary jerking movements, especially in the hands, best demonstrated by having the patient extend their arms in front of them, flex the hands upward, where a subsequent “flapping” can be seen; occurs primarily with various metabolic and toxic encephalopathic conditions, such as hepatic encephalopathy..

Astringent

A substance that causes tissues to constrict, resulting in a drying effect of the skin.