Endocrine Glands

Dr Punita Manik Professor Department of Anatomy K G’s Medical University U P Lucknow Endocrine Glands

Discrete organs Association with organs • Pituitary • Islet of Langerhans (Hypophysis cerebri) • Interstitial cells of Leydig • • Ovarian Follicle & • Parathyroid • Adrenal(Suprarenal) • Chorion • Pineal • Lacis cells, JG cells • Enteroendocrine cells Thyroid Composed • Stroma – capsule and intralobular loose connective tissue • Parenchyma - thyroid follicles Parenchyma-Thyroid

Follicles • Lined by cuboidal epithelium • Height of the follicular cells varies with the secretory activity of the gland • Cells secrete T3 and Lumen filled with colloid or Thyroglobulin- T4 inactive form of thyroid hormones Thyroid • In the same gland, active and resting follicles are seen • Resting • Active • Secretory activity is under the control of TSH of adenohypophysis Thyroid Resting and active Follicle Parafollicular cells

• Also known as C cells of Clear cells • Large pale staining cells , granular cytoplasm • Present either singly or in groups • Within the follicle or between the follicles in the interfollicular space • Those within the follicle lie between the basement membrane and the follicular cells • Secrete Thyrocalcitonin or Calcitonin • Calcitonin lowers blood level Parathyroid • STROMA- capsule and septa • PARENCHYMA- secretory cells arranged in clusters or anastomosing cords • 2 type of cells • Chief cells Or Principal cells • Oxyphil cells Parathyroid Parathyroid

• Chief Cells-small, Basophilic, in large nos • Oxyphil cells- Large, eosinophilic, small no Chief cells- secrete Parathromone or Parathyroid hormone • Parathyroid hormone Increases Calcium Level Decreases phosphate Level in blood Parathyroid Ant & Post Pituitary Cells of

• Granular Cells arranged in irregular cords or clusters • Based on the affinity of granules for specific stains: Chromophils & Chromophobes • Chromophils: Darkly stained because of stained granules • Chromophobes: Poorly stained as no or few granules Cells of Anterior Pituitary Acidophils and Basophils Chromophils

Acidophils Basophils • Shape: Round or oval • Large, rounded or • Stain with orange G or polyhedral Erythrosin • PAS + • Somatotrophs and • Gonadotrophs (LH, Lactotrophs FSH) Thyrotrophs(TSH), • Secrete GH and Corticpotrophs(ACTH Prolactin and MSH) Anterior & Posterior Pituitary

Numerous unmyelinated nerve fibres which are axons of neurons located in the Arising from supraoptic and Paraventricular Nuclei Supporting cells between them are Anterior & Posterior Pituitary Pituitary Gland Adrenal : 3 zones • • • • Cells of cortex has characteristic features of steroid formation: • Cells have many mitochondria with long tubular cristae and smooth endoplasmic reticulum where enzymes for steroid synthesis are found • Secretory activity under the control of ACTH Adrenal

Z. Glomerulosa • Rounded or arched clusters of pyramidal cells, acidophilic cytoplasm with lipid droplets • Fenestrated capillaries are found among the cluster of cells Adrenal Z. Fasciculata • Straight parallel cords cords of polyhedral cells, pale staining cytoplasm with lipid droplets • Lipid droplets give vacuolated or spongy appearance known as spongiocytes • Fenestrated capillaries seen between the cord of cells Zona Glomerulosa and Zona Fasciculata Adrenal Z Reticularis • Small, more acidophilic cells • irregular anastomosing cords of cells • Cells have elongated mitochondria,glycogen, lipofuscin pigments and few lipid droplets • Clumps or cords of chromaffin cells • Polyhedral in shape with few fenestrated capillaries in between • Also contains parasympathetic ganglion cells Adrenal-chromaffin cells

• Derived from Neural crest cells • Are modified sympathetic postganglionic neurons • Stain with chromium salts • Catecholamines are oxidized to brown compound- Chromaffin reaction. Chromaffin cells of Medulla Difference between cells of Cortex and Medulla Cortex Medulla • Under the control of ACTH • Neural Control as innervated by modified sympathetic postganglionic neurons • Cells do not accumulate their hormones in granules. They synthesize and • Cells accumulate and store secrete only on demand secretory products in their granules Adrenal Gland (Epiphysis)

Main cells- - modified Neurons Other cells-Astroglial cells Pineal Gland (Epiphysis)

Brain sand or Corpora arenacea-concentric rings of Ca & Mg Po4 Pineal gland MCQ

• Parafollicular cells are present in which of the following endocrine glands? 1. Parathyroid 2. Suprarenal 3. Thyroid 4. Pancreas MCQ

• Which part of the hypophysis cerebri contains ? 1. Pars anterior 2. Pars posterior 3. 4. MCQ

• Adenohypophysis contains all type of cells EXCEPT? 1.Chromophobes 2. Acidophils 3. Basophils 4. Pituicytes MCQ

• The active follicles of thyroid gland are lined by 1. Simple squamous epithelium 2. Simple cuboidal epithelium 3. Simple columnar epithelium 4. Stratified cuboidal epithelium