fragile X chromosome An X chromosome that has a fragile site and is associated with a common form of mental retardation. Fragile X chromosome is due to a mutation (a trinucleotide repeat) in the DNA at that spot. Not all people who inherit the fragile site have the fragile X syndrome, and it is not…
fragile X syndrome The most common heritable form of mental retardation. Fragile X syndrome is due to a dynamic mutation (a trinucleotide repeat) at an inherited fragile site on the X chromosome; therefore, it is an X-linked disorder. Characteristics of fragile X syndrome in boys may include, in addition to mental impairment, prominent or long…
frambesia See yaws.
FRAXA See fragile X chromosome.
free radical An unstable compound containing unpaired electrons whose behavior is characterized by rapid reactions. Free radicals have been implicated in the aging process, cancer, and other kinds of physical damage to body tissues.
frenulum A physical structure that has a restraining function. For example, the lingual frenulum attaches the tongue to the floor of the mouth and appears to restrain it.
Freudian Pertaining to Sigmund Freud, the neurologist, psychiatrist, and founder of psychoanalysis, or to the theory and practice of psychoanalysis and psychotherapy developed by Freud. Freudian psychoanalysis concentrates on finding the roots of adult behavior in childhood conflicts. The term Freudian also refers to interpretations of behavior based on Freud’s precepts.
Frey syndrome Sweating on one side of the forehead, face, scalp, and neck that occurs soon after ingestion of food, as a result of damage to a nerve that goes to the large saliva gland in the cheek (the parotid gland). The symptoms are usually mild, but more severe cases may require medical treatment.
frontal lobe The part of each hemisphere of the brain located behind the forehead that serves to regulate and mediate the higher intellectual functions. The frontal lobes are important for controlling thoughts, reasoning, and behaviors.
frostbite Damage to tissues that results from exposure to extreme cold. The tissues become injured from blood clotting and ice-crystal formation. Severe frostbite can result in death of the tissues (gangrene). The best way to warm a frozen part is to put it into a tub of hot water at 40°C to 42°C (104°F to…
Forestier disease See diffuse idiopathic skeletal hyperostosis.
formula A prepared substitute for breast milk. Formula does not contain the special immunity factors found in breast milk that help the baby to fight off infections, and it may not include all the vitamins, minerals, and enzymes found in human breast milk. For that reason, experts in infant nutrition agree that breast milk is…