colloid

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colloid

 [kol´oid]
1. gluelike.
2. the translucent, yellowish, gelatinous substance resulting from colloid degeneration.
3. a chemical system composed of a continuous medium (the continuous phase) throughout which are distributed small particles, 1 to 1000 nm in size (the disperse phase), which do not settle out under the influence of gravity. Colloidal particles are not capable of passing through a semipermeable membrane, as in dialysis. Solutes that can pass through a semipermeable membrane are sometimes called crystalloids. adj., adj colloid´al.
dispersion colloid colloid (def. 3), particularly an unstable colloid system.
emulsion colloid lyophilic colloid
rarely, emulsion.
lyophilic colloid a stable colloid system in which the disperse phase is relatively liquid, usually comprising highly complex organic substances, such as glue or starch, which readily absorb solvent, swell, and distribute uniformly through the continuous phase.
lyophobic colloid an unstable colloid system in which the disperse phase particles tend to repel liquids, are easily precipitated, and cannot be redispersed with additional solvent.
stannous sulfur colloid a sulfur colloid containing stannous ions; complexed with technetium 99m it is used as a diagnostic aid (bone, liver, and spleen imaging).
suspension colloid lyophobic colloid.

col·loid

(kol'oyd),
1. Aggregates of atoms or molecules in a finely divided state (submicroscopic), dispersed in a gaseous, liquid, or solid medium, and resisting sedimentation, diffusion, and filtration, thus differing from precipitates.
See also: hydrocolloid.
2. Gluelike.
3. A translucent, yellowish, homogeneous material of the consistency of glue, less fluid than mucoid or mucinoid, found in the cells and tissues in a state of colloid degeneration. Synonym(s): colloidin
4. The stored secretion within follicles of the thyroid gland. For individual colloids not listed below, see the specific name.
[G. kolla, glue, + eidos, appearance]

colloid

(kŏl′oid′)
n.
1. Chemistry
a. A system in which finely divided particles, which are approximately 1 to 1,000 millimicrons in size, are dispersed within a continuous medium in a manner that prevents them from being filtered easily or settled rapidly.
b. The particulate matter so dispersed.
2. The gelatinous stored secretion of the thyroid gland, consisting mainly of thyroglobulin.
3. Gelatinous material resulting from degeneration in diseased tissue.
adj.
Of, relating to, containing, or having the nature of a colloid.

col·loi′dal (kə-loid′l, kŏ-) adj.
col·loi′dal·ly adv.

colloid

Chemistry
A liquid containing 1.0 mm to 1.0 nm microscopic and submicroscopic particles.

Physiology
The thyroglobulin-rich, homogeneous pale pink (by H&E stain) liquid which is secreted into the follicles by the thyroid cells

col·loid

(kol'oyd)
1. Aggregates of atoms or molecules in a finely divided state (submicroscopic), dispersed in a gaseous, liquid, or solid medium, and resisting sedimentation, diffusion, and filtration, thus differing from precipitates.
See also: hydrocolloid
2. Gluelike.
3. A translucent, yellowish, homogeneous material of the consistency of glue, less fluid than mucoid or mucinoid, found in the cells and tissues in a state of colloid degeneration.
Synonym(s): colloidin.
4. The stored secretion within follicles of the thyroid gland.
[G. kolla, glue, + eidos, appearance]

colloid

A substance in which particles are in suspension in a fluid medium. The particles are too small to settle by gravity or to be readily filtered. The colloid state lies between that of a solution and that of an emulsion.

colloid

a mixture of two substances which are immiscible (see MISCIBLE), but where the particles of one are too small to settle out, and so remain suspended indefinitely. Glue is a colloid of animal gelatin in water; the water is defined as the matrix and the gelatin as the inclusion. Colloid particles measure 1 x 10-4 to 1 x 10-6 mm in diameter, forming either a SOL or GEL structure which does not diffuse through cell membranes. Colloids are common in cells, where their large surfaces are important for chemical changes constantly in progress there.

col·loid

(kol'oyd)
Aggregates of atoms or molecules in a finely divided state, dispersed in a gaseous, liquid, or solid medium, and resisting sedimentation, diffusion, and filtration, thus differing from precipitates.
[G. kolla, glue, + eidos, appearance]
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