Dictionary

regenerate To reproduce or renew something that was lost. For example, after an injury, the liver has the capacity to regenerate.

Refsum disease A genetic disorder that affects the metabolism of the fatty acid phytanic acid. When phytanic acid accumulates, it causes a number of progressive problems, including inflammation of numerous nerves (polyneuritis), diminishing vision due to retinitis pigmentosa, and wobbliness (ataxia) caused by damage to the cerebellar portion of the brain. Refsum disease is caused…

refractory Not yielding, or not yielding readily, to treatment.

refraction In opthalmology, the bending of light that takes place within the human eye. Refractive errors include nearsightedness (myopia), farsightedness (hyperopia), and astigmatism. Lenses can be used to control the amount of refraction and correct those errors.

reflux laryngitis See laryngitis, reflux.

reflex sympathetic dystrophy syndrome A condition that features a group of typical symptoms, including pain (often perceived as burning pain), tenderness, and swelling of an extremity. Reflex sympathetic dystrophy syndrome is associated with varying degrees of sweating, warmth and/or coolness, flushing, discoloration, and shiny skin. Its exact cause is unknown. Also known as Complex regional…

reflex An involuntary reaction. For example, the corneal reflex is the blink that occurs upon irritation of the eye.

referred pain Pain felt at a site other than where the cause is situated. An example is the pain from the pancreas, which is felt in the back. Pain in internal organs is often referred to sites distant from them.

referral The recommendation of a medical or paramedical professional. If one gets a referral to ophthalmology, for example, the person is being sent to the eye doctor. In health maintenance organizations (HMOs) and other managed-care schemes, a referral is usually necessary in order to see any practitioner or specialist other than the primary care physician…

Reed-Sternberg cell A type of cell that is seen microscopically in the affected tissues of patients with Hodgkin’s disease and is a hallmark of Hodgkin’s disease. See also Hodgkin’s disease.

reduction division The first cell division in meiosis, the process by which germ cells are formed. In reduction division, the chromosome number is reduced from diploid (46 chromosomes) to haploid (23 chromosomes). Also known as first meiotic division and first meiosis.

red-green colorblindness A form of colorblindness in which red and green are perceived as being identical. Red-green colorblindness is the most common type of colorblindness. It is inherited in an X-linked recessive manner and affects 6-8 percent of males in the US. Also known as deutan colorblindness, deuteranopia, and Daltonism. See also colorblindness.