9.3 POJA-L2794+2801+2803
+2806.
Thyroid gland (V)
9.3 POJA-L2794+2801+2803+2806
Title: Thyroid gland (V)
Description:
(A): Stain hematoxylin-eosin, human. (B): Stain PAS, pig. (C): Electron microscopy scheme, human. (D): Electron microscopy, gerbil.
The thyroid gland comprises numerous follicles (1) with a cyst-like structure in which their inactive product thyroglobulin is stored temporarily. Since the thyroglobulin is a complex with a glycoprotein the follicle colloid is PAS-positive (B).
The follicular cell is involved in the synthesis of the thyroglobulin, the uptake of iodide from the blood, the oxidation of iodine via H2O2, and iodination of the tyrosyl residues of the thyroglobulin (exocrine phase of thyroid). The product leaving the RER in the cell is exported
to the follicular space by exocytosis. The iodine uptake occurs with an iodine pump located at the basal site of the cell (D, 3).
For the peroxidation process the cell uses its peroxidase enzyme. The iodination of the tyrosyl residues takes place, however, in the colloid in the follicular space.
The schematic cell in (C) shows the ample RER, the apical secretory vesicles and the basal-lateral invagination for the iodine uptake.
The same structures can be noticed in the electron micrograph of a follicle in (D). Note the small microvilli at the apical site of the cells within the follicle and the basal invaginations towards the capillary. Most apical dark granules in the follicular cells in (D) are involved in transport of thyroglobulin via colloid vacuoles and lysosomes.
(D, 2) Calcitonin-producing cell or parafollicular cell.
Keywords/Mesh: thyroid gland, follicle cell, histology, electron microscopy, POJA collection
Title: Thyroid gland (V)
Description:
(A): Stain hematoxylin-eosin, human. (B): Stain PAS, pig. (C): Electron microscopy scheme, human. (D): Electron microscopy, gerbil.
The thyroid gland comprises numerous follicles (1) with a cyst-like structure in which their inactive product thyroglobulin is stored temporarily. Since the thyroglobulin is a complex with a glycoprotein the follicle colloid is PAS-positive (B).
The follicular cell is involved in the synthesis of the thyroglobulin, the uptake of iodide from the blood, the oxidation of iodine via H2O2, and iodination of the tyrosyl residues of the thyroglobulin (exocrine phase of thyroid). The product leaving the RER in the cell is exported
to the follicular space by exocytosis. The iodine uptake occurs with an iodine pump located at the basal site of the cell (D, 3).
For the peroxidation process the cell uses its peroxidase enzyme. The iodination of the tyrosyl residues takes place, however, in the colloid in the follicular space.
The schematic cell in (C) shows the ample RER, the apical secretory vesicles and the basal-lateral invagination for the iodine uptake.
The same structures can be noticed in the electron micrograph of a follicle in (D). Note the small microvilli at the apical site of the cells within the follicle and the basal invaginations towards the capillary. Most apical dark granules in the follicular cells in (D) are involved in transport of thyroglobulin via colloid vacuoles and lysosomes.
(D, 2) Calcitonin-producing cell or parafollicular cell.
Keywords/Mesh: thyroid gland, follicle cell, histology, electron microscopy, POJA collection