barrier
(bar'ē-ĕr 
)
[Fr. barriere, a bar]
- An obstacle, impediment, obstruction, boundary, or separation.
- A device (such as a glove, mask, or drape) used to limit potentially infectious contact between health care providers and patients.
architectural b.Any limitation in the design of facilities that restricts their access and use by persons with disabilities.
ABBR: BBB
Any of the special characteristics of the capillary walls of the brain that prevent potentially harmful substances (including medications) from moving out of the bloodstream into the brain or cerebrospinal fluid. It consists of tight junctions in the vascular endothelium lined by the foot processes of astrocytes.blood-nerve b.A physiological barrier between nerves and capillaries that partially blocks the flow of ions from the blood across the perineurium.
chemical b.1Any of the chemical characteristics of certain areas of the body that oppose colonization by microorganisms. The acidity of gastric juice, for example, prevents colonization by most disease-causing germs.2A contraceptive cream, foam, jelly, or suppository that contains chemical spermicides.
glomerular filtration b.The structure of the renal glomerulus that prevents the loss of proteins in the urine, thereby preserving albumin and globulins in the plasma instead of letting them leach into the urine.
language b.Any of the difficulties in communication that arise when patients and their health care providers are not fluent in a common language.
Professionally trained health care interpreters should be employed to bridge communication gaps. The interpreters are known to have better communication with the patient than do family members, concerned lay people, or incompletely trained staff members.
placental b.The selective ability of the placental membranes to limit the exchange of substances between the maternal and fetal circulations. Although water, oxygen and other gases, drugs, necessary nutrients (such as glucose and amino acids), maternal antibodies, and viruses cross the barrier unimpaired, large molecules, red blood cells, bacteria, and protozoa cross it only through breaks in placental integrity.
primary radiation b.A wall or partition that shields the radiographer and other personnel from direct exposure to x-rays. It must be capable of adequate lead equivalency to reduce the maximum possible x-ray beam strength to the level of background exposure.
secondary radiation b.A wall or partition that shields against scattering or leakage of x-rays.