Histology for Pathology Endocrine Organs Objectives Pitutary Gland

Histology for Pathology Endocrine Organs

Objectives Pitutary Gland • On low power and high power sections distinguish the adenohypophysis (anterior pituitary) from the neurohypophysis (posterior pituitary). • List the 2 hormones that are secreted by the hypothalamus and stored in the posterior pituitary. • Define “Hering Body”. • Explain in general terms the staining patterns of chromophobes, basophils and acidophils of the anterior pituitary. • List the 6 hormones secreted by the anterior pituitary and the cell type by which they are each secreted. Thyroid Gland • On H&E stained sections, identify thyroid follicles and colloid. • Describe the cell type that lines thyroid follicles. • List the hormone produced by the parafollicular cells of the thyroid gland.

Parathyroid gland • List the two cell types of the parathyroid glands. Adrenal Gland • On low power distinguish the adrenal cortex from the medulla. • On low power distinguish the zona glomerulosa, zona fasciculata, and zona reticularis and list the hormones secreted by each. • List the substances secreted by the chromaffin cells of the adrenal medulla. Endocrine Pancreas • On low power distinguish the Islets of Langerhans. • List the hormones produced by the alpha, beta, delta and PP cells.

Pituitary Gland Anterior pituitary gland (Adenohypophysis, Pars Distalis) Stains “red-blue” Posterior pituitary gland (Neurohypophysis, Pars Nervosa) Pale staining

Adenohypophysis – high power The adenohypophysis contains 3 cell types: -acidophils (stain red) -basophils (stain blue) -chromophobes (pale stain) The adenohyphysis stains red-blue on low power because of the acidophils and basophils

Why know the cell types of the adenohypophysis? • Acidophils secrete growth hormone and prolactin • Basophils secrete TSH, LH and FSH and ACTH • Chromophobes are undifferentiated cells

Neurohypophysis – high power The neurohypophysis resembles neural tissue, with glial cells, nerve fibers, nerve endings, and intra-axonal neurosecretory granules Precursors of ADH (vasopressin) and oxytocin are synthesized in the hypothalamus and transported to the pars nervosa where processing is completed

Neurohypophysis – high power Hering bodies are large dilated axon terminal endings that are filled with accumulated neurosecretory granules

Thyroid Gland Thyroid Follicles are filled with pink material which is colloid The follicles normally vary in size

Thyroid follicle – high power Normal thyroid follicles are lined by a low cuboidal follicular epithelium

Thyroid gland – high power Parafollicular cells (C-cells) lie between follicles and secrete Calcitonin

Parathyroid Gland – low power Low power of parathyroid, showing random cords of cells. The parathyroid is somewhat lobulated in appearance and considerable adipose tissue is intermingled with secretory portions. Adipose tissue Cords of cells

Parathyroid Gland – high power Chief cells Oxyphil cells 2 cells types of the Parathyroid: Chief cells secrete parathormone (PTH). They have large round nuclei with a small amount of clear cytoplasm. Oxyphil cells have smaller, darker nuclei and relatively larger amount of cytoplasm. The significance of the oxyphil cells is not clear.

Adrenal Gland – Low power capsule cortex medulla

Adrenal Cortex –low power Zona glomerulosa Mineralocorticoids aldosterone Zona fasciculata Glucocorticoids – Cortisol, corticosterone Zona reticularis Androgens– dehydroepiandrosteron e

Endocrine Pancreas Islets of Langerhans Low power High power

Endocrine Pancreas • Cells in the islets of Langerhans – Alpha – secrete glucagon – Beta – secrete insulin – Delta – secrete somatostatin and gastrin – PP – secrete pancreatic polypeptide