. The endocrine organs; an introduction to the study of internal secretion . • FIG. SB.—Section of thyroid of another wild rat. Magnified250 diameters. The vesicles contain little or no colloid ;the epithelial cells are columnar. (Chalmers Watson.) the tongue. 16 The Endocrine Organs again and again to form a system of hollow epithelium-lined tubes, andlater these become cut up into the closed vesicles which are characteristicof the gland. The thyroid bud is joined by outgrowths from the ventral. FIG. 7.—Section of parathyroid (cat). Magnified 400 diameters. This is a goodillustration of th
. The endocrine organs; an introduction to the study of internal secretion . • FIG. SB.—Section of thyroid of another wild rat. Magnified250 diameters. The vesicles contain little or no colloid ;the epithelial cells are columnar. (Chalmers Watson.) the tongue. 16 The Endocrine Organs again and again to form a system of hollow epithelium-lined tubes, andlater these become cut up into the closed vesicles which are characteristicof the gland. The thyroid bud is joined by outgrowths from the ventral. FIG. 7.—Section of parathyroid (cat). Magnified 400 diameters. This is a goodillustration of the compact type of gland. wall of the pharynx on each side behind the fourth branchial pouch (post-branchial bodies); these may be involved in the thyroid, but it is doubtfulif they contribute to the formation of its vesicles. STRUCTURE AND DEVELOPMENT OF PARATHYROIDS Structure.—The parathyroids (fig. 1) are four minute organs averaging6 to 7 mm. in length, 3 to 4 mm. broad, and 15 to 2 mm. thick (Welsh).Each weighs about 003 gramme (half a grain). Rarely there are morethan four, sometimes fewer. As already stated, one (the lower) mayoccur altogether detached from the thyroid,1 but usually in man both areclosely attached to it. The upper of the parathyroids may be completelyembedded in the substance of the thyroid (fig. 13). The parathyroids were described by Sandstrom in 1880. Their plwsio-logical independence and distinction from the thyroid proper was first re-cognised by Gley in 1891,
Size: 1880px × 1329px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1900, bookdecade1910, bookidendocrineorgansi00shar
