Endocrine System PDF

SPECIAL HISTOLOGY Endocrine system Dra. Sabina Sanegre Dept. Ciencias Biomédicas [email protected]  ENDOCRINE It is characterized by having parenchymal cells that release their secretion products directly into the blood It...

SPECIAL HISTOLOGY Endocrine system Dra. Sabina Sanegre Dept. Ciencias Biomédicas [email protected]  ENDOCRINE It is characterized by having parenchymal cells that release their secretion products directly into the blood It comprises the endocrine glands and groups of isolated cells that are part of non-endocrine organs. - Organs: pituitary, pineal,thyroid, parathyroid, and adrenal gl. - Groups of cels. Neuroendocrine (diffuse neuroendocrine system, DES): Pancreatic islets, digestive tract, respiratory system, atrial myocardial, etc. Hormones regulate the functions of cells in general or specific tissues or organs, called target organs. The endocrine system, along with nervous system, is involved in the maintenance of the body homeostasis.  Gartner y Hiatt. Atlas en Color y Texto de Histología PITUITARY GLAND 4 PITUITARY GLAND 6 PITUITARY GLAND 7  PITUITARY GLAND Adenohypophysis and Neurohypophysis -Capsule: irregular dens CT. - Adenohypophysis (anterior lobe): Pars tuberalis. Pars intermedia. Pars distalis. - Neurohypofysis (posterior lobe): Median eminence. infundibulum. pars nervosa.  PITUITARY GLAND Pars Distalis In the adenohypophysis. Clusters of cell cords + dense network of sinusoid capillaries. scarce CT.  PITUITARY GLAND Pars Distalis 3 main types of parenchymal cells: - Acidophilic (A): GH, PRL. - Basophilic (B) bigger: ACTH, GN (FSH and LH), TSH - Cromophobes (Cp): sparse cytoplasm, they stain weakly. Smaller and become more obvious in a group. Cells that have already released their granules with hormones. Growth hormone (GH) Prolactine (PRL) Adrenocorticotropa (ACTH) Gonadotropins (Gn) Thyroid-stimulating hormone (TSH). Azán modificado 11 13  PITUITARY GLAND Pars Intermedia In the adenohypophysis. Not very developed in humans. The most abundant cell type is a large, loosely stained cell (basophil) that can surround colloid-filled follicles  PITUITARY GLAND Pars Nervosa 16  PITUITARY GLAND Pars Nervosa In Neurohypophysis. It has no characteristic epithelium, fibrous and disorganized appearance. Sinusoids. Composed of pituycytes (neuroglia) to support the myelinated axons of cells located in the hypothalamus. Herring's bodies: terminal dilation of axons with oxytocin, and ADH (antidiuretic) inside. Mallory's Trichrome 18 HE PAS/blue-black aniline 19 20 HE PAS/blue-black aniline 21  THYROID Two lobes interconnected by narrow isthmus in the superior trachea. It is surrounded by a thin capsule of irregular dense CT (from which trabeculae penetrate, forming the supporting stroma and the pathway for vessels). Interstitial space with dense networks of sinusoid and lymphatic capillaries. It is made up of numerous follicles, usually filled with colloid substance.  THYROID It is made up of numerous follicles, usually filled with colloid. o Follicular Cells: simple cubic-cylindrical ep. linning the follicles. Thyroid hormone = colloid. o Parafoliculares cells or C cells: (out of follicles, not in contact with the colloid). They produce calcitonin (regulates the concentration of Ca in the blood).  PARATHYROID Variable number of nodules (usually 4). A dense CT capsule that emits septa carrying vessels. There number of adipocytes increases with age. Gartner y Hiatt. Atlas en Color y Texto de Histología  PARATHYROID It is made up of 2 types of cells organized in cords surrounding capillaries: Prinicpal cells or chief cells (parathyroid (PTH), maintain Ca+ balance): smaller and more numerous (C). Oxyphiles cells or acidophilic (A)  SUPRARENAL (= Adrenal) Formed by cortex and medulla. Surrounded by a thin capsule of dense CT. Fine trabeculae originate from the capsule and penetrate the cortex, but do not usually reach the medula. Blood vessels penetrate the parenchyma inside the trabeculae. Gartner y Hiatt. Atlas en Color y Texto de Histología SUPRARENAL (= Adrenal)  SUPRARENAL (= Adrenal) CORTEX: 3 concentric zones that secrete specific hormones under regulation of the ACTH of the pituitary gland. - Glomerulosa: Cells arranged in spheroidal arcs and clusters. Lots of capillaries. Aldosterone. - Fasciculata: The + extensive. Cubic or cylindrical cell cords called spongiocytes, capillaries between the cords, radial shape. Cortisol and corticosterone. - Reticularis: Androgens. Irregular network of anastomosed cell cords, with extensive capillary network. 37  SUPRARRENAL (= Adrenal) CORTEX: (glomerular, fascicular and reticular zone) MEDULLA: Groups of secretory parenchymal cels densely arranged in cords surrounded by networks of capillaries and supported by a thin layer of CT. Chromaffin cells: - A cells (adrenaline or epinephrine) - NA cells (noreadrenaline or norepinephrine) They are neurotransmitters. Stimulation via SNS (stress)  PINEAL (=epiphysis) How it works in humans is not well understood.* Projection of the roof of the diencephalon. The connective tissue that surrounds it is the Pia Mater, which emits trabeculae inwards to divide it into incomplete lobules. There are also blood vessels and nerve fibers that lose their myelin when they enter this gland. Parenchyma: - Pinealocytes arranged in clumps or cords, that establish links with each other (=communicating maculae) and produce melatonin (only at night, it receives afferents from the retina, contributes to establishing *circadian rhythm) - Interstitial cells (glia), support the previous ones. - Extracellular spaces with calcified granular material (brain sand) of unknown importance. Gartner y Hiatt. Atlas en Color y Texto de Histología PINEAL 44 LET´S HAVE A LOOK AT SOME SLIDES… 45 ENDOCRINE PANCREAS Objectives to identify: Capsule Endocrine pancreas (Islets of Langerhans) Exocrine pancreas Pacinian corpuscle Parasympathetic ganglion Excretory ducts and their epithelia 46 Identify: Endocrine pancreas Exocrine pancreas Islet of Langerhans Fenestrated capillaries Identify: Pacinian corpuscle Parasympathetic ganglion Neuronal soma Satellite cells ADRENAL GLAND To identify: Capsule Cortex Glomerular zone Reticular zone Fascicular zone Medulla Medullary cells Anterior lobe or adenohypophysis Posterior lobe or neurohypophysis What lobe of the pituitary gland appears in the microphotograph? What are pituicytes? Point out a Herring body:  Capillaries Acidophilic cells Basophilic cells Chromophobe cells  Thyroid or pituitary? What do we call this structure?  Key insights Characteristics, structure and identification of the different glands. EJERECICIO INTERPRETACIÓN DE TALLADO 2 1 D 3 4 5 6