1. A nonsolid substance, such as a liquid or gas, that tends to flow or conform to the shape of the container. 2. Consisting of particles or distinct entities that can readily change their relative positions; i.e., tending to move or capable of flowing. [L. fluidus, fr. fluo, to flow]
- amnionic f. a liquid within the amnion that surrounds the fetus and protects it from mechanical injury. SYN: liquor amnii.
- Brodie f. an aqueous salt solution used in manometers designed for testing gas evolution or uptake, as in cell respiration.
- bronchoalveolar f. a f. containing several lytic enzymes that serves to remove inspired particulates from the pulmonary airways.
- Callison f. a diluting f. for counting red blood cells, consisting of 1 ml of Loeffler alkaline methylene blue, 1 ml of formalin, 10 ml of glycerol, 1 g of neutral ammonium oxalate, and 2.5 g of sodium chloride added to 90 ml of distilled water, mixed well, and permitted to stand until the solids are dissolved and the reagent is clear; the preparation is filtered prior to use.
- cerebrospinal f. (CSF) [TA] a f. largely secreted by the choroid plexuses of the ventricles of the brain, filling the ventricles and the subarachnoid cavities of the brain and spinal cord. SYN: liquor cerebrospinalis [TA].
- crevicular f. SYN: gingival f..
- dentinal f. the lymph or f. of dentin which appears on the surface of freshly cut dentin, especially in young teeth; it is a transudate of extracellular f., mainly cytoplasm of odontoblastic processes, from the dental pulp via the dentinal tubules. SYN: dental lymph.
- extracellular f. (ECF) 1. the interstitial f. and the plasma, constituting about 20% of the weight of the body; 2. sometimes used to mean all f. outside of cells, usually excluding transcellular f..
- extravascular f. all f. outside the blood vessel s, i.e., intracellular, interstitial, and transcellular fluids; it constitutes about 48 to 58% of the body weight.
- Farrant mounting f. an aqueous solution containing gum arabic, arsenic trioxide, glycerol, and water, used in mounting histologic sections directly from water; some modifications involve addition of potassium acetate to bring the pH up to neutrality and substitution of other preservatives like cresol or thymol for arsenic trioxide.
- gingival f. f. containing plasma proteins, which is present in increasing amounts in association with gingival inflammation. SYN: crevicular f., sulcular f..
- infranatant f. clear f. that, after the settling out of an insoluble liquid or solid by the action of normal gravity or of centrifugal force, takes up the lower portion of the contents of a vessel.
- interstitial f. the f. in spaces between the tissue cells, constituting about 16% of the weight of the body; closely similar in composition to lymph. SYN: tissue f..
- intracellular f. (ICF) the f. within the tissue cells, constituting about 30–40% of the body weight. SYN: intracellular water.
- intraocular f. SYN: aqueous humor.
- newtonian f. a f. in which flow and rate of shear are always proportional to the applied stress; such f. precisely obeys Poiseuille law. Cf.:non-newtonian f..
- non-newtonian f. a f. in which flow and rate of shear are not always proportional to the applied stress and which does not obey Poiseuille law. As in anomalous viscosity; Fahraeus-Lindqvist effect; Bingham plastic. Cf.:newtonian f..
- pleural f. the thin film of f. between the visceral and parietal pleurae. May significantly increase in disease states, when termed pleural effusion.
- prostatic f. succus prostaticus; a whitish secretion that is one of the constituents of the semen.
- Rees-Ecker f. an aqueous solution of sodium citrate, sucrose, and brilliant cresyl blue used in platelet counts.
- sulcular f. SYN: gingival f..
- supernatant f. clear f. that, after the settling out of an insoluble liquid or solid by the action of normal gravity or of centrifugal force, takes up the upper portion of the contents of a vessel.
- synovial f. [TA] a clear thixotropic f., the main function of which is to serve as a lubricant in a joint, tendon sheath, or bursa; consists mainly of mucin with some albumin, fat, epithelium, and leukocytes; synovial f. also helps to nourish the avascular articular cartilage. SYN: synovia [TA], joint oil.
- thixotropic f. a liquid that tends to turn into a gel when left standing, but which turns back into a liquid if agitated, as by vibrations or subjection to adequate shear.
- tissue f. SYN: interstitial f..
- transcellular fluids the fluids that are not inside cells, but are separated from plasma and interstitial f. by cellular barriers; e.g., cerebrospinal f., synovial f., pleural f..
- ventricular f. the portion of the cerebrospinal f. that is contained in the ventricles of the brain.
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flu·id 'flü-əd adj having particles that easily move and change their relative position without a separation of the mass and that easily yield to pressure: capable of flowing
fluid n a substance (as a liquid or gas) tending to flow or conform to the outline of its container specif one in the body of an animal or plant see CEREBROSPINAL FLUID, SEMINAL FLUID
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flu·id (flooґid) [L. fluidus] 1. a liquid or a gas. 2. composed of elements or particles which freely change their relative positions without separating. See also humor, liquid, liquor, and solution.Medical dictionary. 2011.