Medical terms - Letter R (page 4) | MedicalVocabulary.org

Reaction, polymerase chain

See: Vasovagal reaction.
Reaction, vasovagal

See: Vasovagal reaction
Reactive arthritis

Reactive arthritis: A chronic form of arthritis featuring the following three conditions: (1) inflamed joints; (2) inflammation of the eyes (conjunctivitis); and (3) inflammation of the genital, urinary or…
Reactive oxygen species

Species such as superoxide, hydrogen peroxide, and hydroxyl radical. At low levels, these species may function in cell signalling processes. At higher levels, these species may damage cellular macromolecules (such as…
Reading frame

One of the three possible ways to read a nucleotide sequence in DNA or RNA as a series of nonoverlapping triplets, depending upon whether reading starts with the first, second or third base in the sequence. For example…
Reading frame, open

See: Open reading frame
Reading retardation

Reading retardation means impaired ability to read. Reading retardation is an impairment that may, for example, reflect mental retardation or cultural deprivation. Reading retardation is different from dyslexia, a…
Reagent

A substance used to produce a chemical reaction to detect, measure, produce, etc. other substances
Reaven syndrome

See: Metabolic syndrome
Rebound

Return of the original symptoms when maneuvers or treatment is discontinued
Rebound effect

The characteristic of a drug to produce reverse effects when the effect of the drug has passed or the patient no longer responds to it
Recalcitrant

Stubborn. For example, a recalcitrant case of pneumonia stubbornly resists treatment
Recalls, FDA

Recalls: The recall of a defective or possibly harmful product by the US Food & Drug Administration (the FDA). These recalls are often highly publicized in newspapers and on radio and TV news broadcasts. Recent…
Recent memory

Short-term memory. Also called working memory. Recent memory is a system for temporarily storing and managing the information required to carry out complex cognitive tasks such as learning, reasoning, and comprehension…
Receptor

1. In cell biology, a structure on the surface of a cell (or inside a cell) that selectively receives and binds a specific substance. There are many receptors. There is a receptor for (insulin; there is a receptor for…
Receptor, chemokine

Receptor, chemokine: A molecule that receives a chemokine and a chemokine dock. A chemokine is a protein that acts as a lure. Chemokines are involved in inflammation, cancer, and infectious diseases. Several chemokine…
Receptor, T-cell

A molecule on the surface of T-lymphocytes (T-cells) for recognizing specific antigens (foreign substances or microbes such as viruses)
Receptor, visual

The layer of rods and cones, the visual cells, of the retina
Recessive

A condition that appears only in individuals who have received two copies of a mutant gene, one copy from each parent. The individuals with a double dose of the mutated gene are called homozygotes. Their parents, each…
Recessive, autosomal

A genetic condition that appears only in individuals who have received two copies of an autosomal gene, one copy from each parent. The gene is on an autosome, a nonsex chromosome. The parents are carriers who have only…
Recessive, X-linked

A gene on the X chromosome that expresses itself only when there is no different gene present at that locus (spot on the chromosome). For example, Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder. A…
Recipient

In medicine, a recipient is someone who receives something like a blood transfusion or an organ transplant. The recipient is beholden to the donor
Reciprocal translocation

A type of chromosome rearrangement involving the exchange of chromosome segments between two chromosomes that do not belong to the same pair of chromosomes. A specific reciprocal translocation might, for example…
Recombinant

A person with a new combination of genes, a combination of genes not present in either parent, due to parental recombination of those genes
Recombinant clones

Clones containing recombinant DNA molecules.
Recombinant DNA Advisory Committee (RAC)

The National Institutes of Health (NIH) panel that oversees gene-therapy research in the U.S
Recombinant DNA molecules

A combination of DNA molecules of different origin that are joined using recombinant DNA technology
Recombinant DNA technology

A series of procedures used to join together (recombine) DNA segments. A recombinant DNA molecule is constructed (recombined) from segments from 2 or more different DNA molecules. Under certain conditions, a recombinant…
Recombinant tPA

Recombinant tissue plasminogen activator. See: Tissue plasminogen activator
Recombination

The trading of fragments of genetic material between chromosomes before the egg and sperm cells are created. Key features of recombination include the point-to-point association of paired chromosomes (synapsis) followed…
RECOMBIVAX-HB

A vaccine against hepatitis B (hep B) to stimulate the body's immune system to produce antibodies against the hep B virus
Recommended Daily Allowance

Popular name for the Recommended Dietary Allowance (RDA)
Recommended Dietary Allowance

The RDA, the estimated amount of a nutrient (or calories) per day considered necessary for the maintenance of good health by the Food and Nutrition Board of the National Research Council/ National Academy of Sciences…
Recreational water illness

An illness that is spread by swallowing, breathing, or having contact with contaminated water from swimming pools, spas, hot tubs, decorative water fountains, lakes, rivers, or oceans. Recreational water illnesses…
Recrudescence

Reappearance of a disease after it has been quiescent. A new outbreak or the return of a disease. As, for example, the recrudescence of a pansinusitis (sinusitis, an infection involving all of the sinuses). The original…
Rectal (adjective)

Having to do with the rectum, the last 6 to 8 inches of the large intestine that serves to store solid waste until it leaves the body through the anus. The word 'rectal' comes from the Latin 'rectus' meaning 'straight'…
Rectal (noun)

An informal term for a digital rectal exam (DRE) done to detect abnormalities that can be felt (palpated) from within the rectum. The doctor inserts a lubricated, gloved finger into the rectum and feels for anything…
Rectal bleeding

Rectal bleeding: Blood passed rectally. Blood in the stool can be bright red or maroon in color. Larger amounts of blood that remain in the intestine long enough can turn the stool black. Blood in the stool also may be…
Rectal cancer

Cancer: A malignant tumor arising from the inner wall of the final part of the large intestine -- the rectum. Although colon cancer and rectal cancer share many features, there are important differences between these…
Rectal exam, digital (DRE)

An exam done to detect abnormalities that can be felt (palpated) from within the rectum. The doctor inserts a lubricated, gloved finger into the rectum and feels for anything that is not normal. The digital rectal exam…
Rectal incontinence

Inability to hold feces in the rectum due to failure of voluntary control over the anal sphincters with involuntary passage of feces and gas. Also called fecal incontinence.
Rectal itching

See Anal itching
Rectocele

Bulging of the front wall of the rectum into the vagina. Rectocele is due to weakening of the pelvic support structures and thinning of the rectovaginal septum (the tissues separating the rectum from the vagina). Also…
Rectouterine pouch

>Culdoscopy, the introduction of an endoscope through the vagina into the cul-de-sac; >Culdoscope, the endoscope that is used to look into the cul-de-sac; and >Culdocentesis, the aspiration (withdrawal) of fluid from…
Rectum

The last 6 to 8 inches of the large intestine. The rectum stores solid waste until it leaves the body through the anus. The word rectum comes from the Latin rectus meaning straight (which the human rectum is not)
Rectus

Usually refers to the rectus abdominis, a large muscle in the front of the abdomen that assists in the regular breathing movement and supports the muscles of the spine while lifting and keeping abdominal organs such as…
Rectus abdominis

A large muscle in the front of the abdomen that assists in the regular breathing movement and supports the muscles of the spine while lifting and keeping abdominal organs such as the intestines in place. The rectus…
Recuperate

To recover health and strength. From the Latin recuperare meaning to regain, get back, recover. To recuperate is to convalesce
Recur

To occur again. To return. Any symptom (such as fatigue), any sign (such as a heart murmur), or any disease can recur.
Recurrence

The return of a sign, symptom or disease after a remission. The reappearance of cancer cells at the same site or in another location is, unfortunately, a familiar form of recurrence. A recurrence or relapse occur after…