Quain's elements of anatomy . certainly the case in some of thesmall mucous glands of the mouth in which no marginal cells can be seen. It isprobable however that in the salivary glands, some at least of the mucin-cells areentirely destroyed, and the marginal cells multiplying and becoming filled withsecretion, serve to replace those which are thus lost. In this way we maysu]ipose that, even while the discharge of secretion is still proceeding, newsecreting cells are forming, at the same time that some of the older ones arebeing destroyed (Heidenhain). jSerous alveoli.—In the serous elands and
Quain's elements of anatomy . certainly the case in some of thesmall mucous glands of the mouth in which no marginal cells can be seen. It isprobable however that in the salivary glands, some at least of the mucin-cells areentirely destroyed, and the marginal cells multiplying and becoming filled withsecretion, serve to replace those which are thus lost. In this way we maysu]ipose that, even while the discharge of secretion is still proceeding, newsecreting cells are forming, at the same time that some of the older ones arebeing destroyed (Heidenhain). jSerous alveoli.—In the serous elands and serous alveoli of mixed SEROUS ALVEOLI. 531 glands, the cells, in the inactive condition of the glands, are in the fresh con-dition and in osmic preparations seen to be packed full of distinct granules,of an albuminous nature, which obscure their nuclei. The granules areimbedded in the protoplasm of the cells and the latter almost completelyfill the alveoli, scarcely any lumen being discernible (fig. 50G, A). Fig. 506. A ^. Fig. 506.—Alveoli oi* seeous glands. A, at kest. B, after a short periodOP activity. C, after a prolokged period of ACTiTiTr. ? (Laugley.) After a sliorfc period of activity the granules are foimd to liave disappeared inthe outer part of the cell, the inner part being still distinctly granular and somegranules being apparently free within the lumen of the alveolus, now becomingdistinct (fig. .50(;, B). With more prolonged activity (fig. .50G, C) the clearouter part increases in extent, and the granules are found only in the part of thecell which is close to the lumen, and in those parts which are contiguous to theadjacent cells, (coiTCsponding perhaps to fine capillary clefts which pass from thecavity of the alveolus between the cells). The nuclei have now become distinct, Fig. 507.—Section op the SCBMAXILLARr GLAND OFTHE DOG, SHOWING THECOMJIENCEMENT of a DUCTIN THE ALVEOLI. MAG-NIFIED 425 DIAMETERS.(E. A. S.). a, one of the alveoli, severalof which
Size: 2421px × 1032px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1800, booksubjectanatomy, booksubjecthumananatomy
