The Histology of Endocrine Glands Dr. Tatiana Jones, MD, PhD NCC Hypophysis (Pituitary Gland) It is a collection of different cell types that control the activity of other endocrine organs. The pituitary is divided into the darker staining anterior pituitary and lighter staining posterior pituitary. The posterior pituitary is connected to the hypothalamus by the pituitary stalk. The stalk contains axons of neurons whose cell bodies reside in the hypothalamus and that release their hormones in the posterior pituitary. The Posterior Pituitary (Neurohypophysis) Derived from the hypothalamus. Composed of unmyelinated axonal processes (cell bodies reside in the hypothalamus). The neurons release the releasing hormones, as well as oxytocin and vasopressin (ADH). The pituitary stalk connects the hypothalamus and pituitary. The posterior pituitary also has characteristic Herring bodies, which are focal axonal swellings packed with secretory granules. Most of the cells visible in the slide belong to supporting cells, pituicytes, the glial cells of the pituitary gland. The Anterior Pituitary (Adenohypophysis) The anterior pituitary is also known as the adenohypophysis. It contains cells that, when stained by H&E, appear as acidophils, basophils, or chromophobes. Cells of Adenohypophysis The Thyroid Gland Isthmus Right Left lobe lobe Calcitonin T4 or Thyroxine T3 or Triiodothyronine The Parathyroid Gland Chief (principal) cells, which have prominent central nuclei surrounded by pale cytoplasm. Chief cells produce parathyroid hormone (PTH), which is the most important regulator of calcium metabolism in humans. When serum calcium levels fall, chief cells release PTH which indirectly stimulates the production of osteoclasts in bone. Oxyphilic cells, which are large and fewer in number, have small, dark nuclei and an acidophilic cytoplasm with many mitochondria. The function of these cells is unknown, but they increase in abundance as a person ages. Adrenal or Suprarenal Glands Medulla (It is considered part of Sympathetic Autonomic nervous System) Catecholamines (Epinephrine and Norepinephrine) Sex hormones ( androgens) Glucocorticoids (Cortisol, Cortisone and Corticosterone) Mineralocorticoids (Aldosterone) The Pancreas Endocrine pancreas Exocrine pancreas Islets of Langerhans Pancreatic acini 1- Beta cells: Insulin They secrete large quantities of an alkaline, enzyme rich fluid 2- Alpha cells: Glucagon 3- Delta cells: Somatostatin 4- F cells: Pancreatic polypeptide.