ENDOCRINE This resource is licensed under the Creative

Objectives 1. To describe the gross structure of the pituitary gland be able to

Equine Head/Brain section locate Pituitary (Hypophysis)

Equine Head/Brain section locate Pituitary (Hypophysis) 1 2 3 4 5 6 1 1

SLIDE 159 Pituitary gland (hypophysis) At low magnification identify the main areas of the

SLIDE 159 Pituitary gland (hypophysis) What are the principal secretory products of B, C

SLIDE 159 Pituitary gland (hypophysis) The pars distalis is separated from the pars intermedia.

SLIDE 159 Pituitary gland (hypophysis) Area of the pars distalis, identify : chromophilic cells

SLIDE 159 Pituitary gland (hypophysis) Area of the pars intermedia, identify : epithelioid cells

SLIDE 159 Pituitary gland (hypophysis) Area of the neurohypophysis, the pars nervosa. Identify :

SLIDE 159 Pituitary gland (hypophysis) What are Herring bodies? 25 µm

SLIDE 159 Pituitary gland (hypophysis) What are Herring bodies? Accumulations of neurosecretions at the

SLIDE 158 Pituitary gland (hypophysis) This section has been stained to show the chromophils

SLIDE 158 Pituitary gland (hypophysis) Pars distalis : The chromophils have stained well, the

SLIDE 151 Thyroid gland Whole section viewed under low power. 1. 0 mm

SLIDE 151 Thyroid gland Whole section viewed under low power. trachea thyroid gland lumen

SLIDE 151 Thyroid gland Note the different sized follicles and the connective tissue capsule

SLIDE 151 Thyroid gland Thyroid viewed at higher power. What substance fills each follicle?

SLIDE 151 Thyroid gland Thyroid viewed at high power. What changes would be evident

SLIDE 151 Thyroid gland Where are ‘C’ cells located? 50 µm

SLIDE 151 Thyroid gland Where are ‘C’ cells located? C cells also called parafollicular

SLIDE 151 Thyroid gland What is the secretory product of C cells? 25 µm

SLIDE 151 Thyroid gland What is the secretory product of C cells? Calcitonin :

SLIDE 153 Parathyroid glands At low magnification note that these glands lie within the

SLIDE 153 Parathyroid glands The parenchymal cells form cords and are highly vascularised. What

SLIDE 153 Parathyroid glands What do the principal cells produce? 100 µm

SLIDE 153 Parathyroid glands What do the principal cells produce? Parathyroid hormone (PTH). capsule

SLIDE 153 Parathyroid glands What conditions would result in the release of this hormone?

SLIDE 24 Pancreas rat (H and E stain) At low magnification identify and locate

SLIDE 24 Pancreas rat (H and E stain) With Haematoxylin and eosin the acini

SLIDE 157 Pancreas (Gomori stain) The H & E stain showed the pale pink

SLIDE 157 Pancreas (Gomori stain) What cell types are present in an islet and

SLIDE 157 Pancreas (Gomori stain) How many cell types can be identified based on

SLIDE 157 Pancreas (Gomori stain) Which islet hormone will increase glycogenolysis? α β 50

SLIDE 157 Pancreas (Gomori stain) Which islet hormone will increase glycogenolysis? Glucagon. α β

SLIDE 157 Pancreas (Gomori stain) Which islet hormone will increase glycogenolysis? Glucagon. In which

SLIDE 155 Adrenal gland Seen at low magnification, identify the zones of the adrenal

SLIDE 155 Adrenal gland At a slightly higher magnification the zona glomerulosa and zona

SLIDE 155 Adrenal gland Cortex. Zona Glomerulosa : The cells in the zona glomerulosa

SLIDE 155 Adrenal gland Cortex. Zona Fasciculata : The zona fasciculata forms the widest

SLIDE 155 Adrenal gland Cortex. Zona Fasciculata : The cells in the zona fasciculata

SLIDE 155 Adrenal gland Cortex. Zona Reticularis : This is the inner zone of

SLIDE 155 Adrenal gland Cortex. Zona Reticularis : The cells in the zona reticularis

SLIDE 155 Adrenal gland Medulla : The adrenal medulla consists of columnar or polyhedral

SLIDE 155 Adrenal glands What are the hormonal products of each of these zones?

SLIDE 156 Adrenal gland cat (Sudan black stain) Stained with Sudan black for lipid.

SLIDE 156 Adrenal gland cat (Sudan black stain) Would the number of lipid droplets

SLIDE 156 Adrenal gland cat (Sudan black stain) How is the release of catecholamines

Lectures. Dr R Fowkes. Lectures. Dr C Wheeler-Jones. Second Year Histology. O 20. ENDOCRINES.

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Objectives 1. To describe the gross structure of the pituitary gland be able to identify the pars nervosa, pars intermedia and pars distalis. 2. Identify and describe the histological features of the pars nervosa and pars distalis and be able to relate these features to the different modes of hormone secretion. 3. Identify and describe the histological features of the thyroid and parathyroid glands. 4. Identify and describe the histological features of the pancreatic Islets of Langerhans. 5. Identify and describe the histological features of the adrenal gland; in particular the different regions of the adrenal cortex.

Equine Head/Brain section locate Pituitary (Hypophysis)

Equine Head/Brain section locate Pituitary (Hypophysis) 1 2 3 4 5 6 1 1 corpus callosum ix rn fo 5 cerebellum 6 2 4 3 po ns me du lla Cerebrum Optic nerve/chiasm Pituitary (Hypophysis) Mamillary body Interthalamic adhesion Aqueduct of Sylvius

SLIDE 159 Pituitary gland (hypophysis) At low magnification identify the main areas of the gland : A. B. C. D. A D B 1. 0 mm C

SLIDE 159 Pituitary gland (hypophysis) At low magnification identify the main areas of the gland : A. B. C. D. Pars tuberalis. Pars distalis. Pars intermedia. Pars nervosa. A D B 1. 0 mm C

SLIDE 159 Pituitary gland (hypophysis) At low magnification identify the main areas of the gland : A. B. C. D. Pars tuberalis. Pars distalis. Pars intermedia. Pars nervosa. A, B, C form the anterior hypophysis (adenohypophysis). D forms the posterior hypophysis (neurohypophysis). A D B 1. 0 mm C

SLIDE 159 Pituitary gland (hypophysis) What are the principal secretory products of B, C and D? (The pars tuberalis contains secretory cells whose function is unknown). median eminence A : pars tuberalis B : pars distalis C : pars intermedia D : pars nervosa A D B C 1. 0 mm

SLIDE 159 Pituitary gland (hypophysis) What are the principal secretory products of B, C and D? B : somatotropin, prolactin, FSH (follicle-stimulating hormone), LH (luteinizing hormone), TSH (thyroid-stimulating hormone), ACTH (adrenocorticotropic hormone). median eminence A : pars tuberalis B : pars distalis C : pars intermedia D : pars nervosa A D B C 1. 0 mm

SLIDE 159 Pituitary gland (hypophysis) What are the principal secretory products of B, C and D? C : MSH (melanocyte-stimulating hormone). median eminence A : pars tuberalis B : pars distalis C : pars intermedia D : pars nervosa A D B C 1. 0 mm

SLIDE 159 Pituitary gland (hypophysis) What are the principal secretory products of B, C and D? D : oxytocin, ADH (antidiuretic hormone or vasopressin). median eminence A : pars tuberalis B : pars distalis C : pars intermedia D : pars nervosa A D B C 1. 0 mm

SLIDE 159 Pituitary gland (hypophysis) The pars distalis is separated from the pars intermedia. This space is the residual lumen of Rathke’s pouch (from which the anterior hypophysis develops) and is called the hypophysial cleft. The pars nervosa lies next to the pars intermedia. 250 µm

SLIDE 159 Pituitary gland (hypophysis) Area of the pars distalis, identify : chromophilic cells chromophobes a). acidophils (staining red). b). Basophils (pale-blue staining). seen as clusters of nuclei. 25 µm

SLIDE 159 Pituitary gland (hypophysis) Area of the pars distalis, identify : chromophilic cells chromophobes A a). acidophils (staining red). b). Basophils (pale-blue staining). seen as clusters of nuclei. A : acidophils B : basophils C : chromophobes S : sinusoid S blood vessel B C S 25 µm

SLIDE 159 Pituitary gland (hypophysis) Area of the pars intermedia, identify : epithelioid cells 50 µm

SLIDE 159 Pituitary gland (hypophysis) Area of the pars intermedia, identify : epithelioid cells pars nervosa pars intermedia pars distalis hypophyseal cleft (Rathke’s cleft) 50 µm

SLIDE 159 Pituitary gland (hypophysis) Area of the neurohypophysis, the pars nervosa. Identify : pituicytes (neuroglia-like cells). Herring bodies. 25 µm

SLIDE 159 Pituitary gland (hypophysis) Area of the neurohypophysis, the pars nervosa. Identify : pituicytes (neuroglia-like cells). Herring bodies. H : Herring bodies P : pituicytes H P H blood vessels H 25 µm

SLIDE 159 Pituitary gland (hypophysis) What are Herring bodies? 25 µm

SLIDE 159 Pituitary gland (hypophysis) What are Herring bodies? Accumulations of neurosecretions at the terminal regions of nerve fibres. Note the rich vasculature of this region. H : Herring bodies P H P : pituicytes blood vessels 25 µm

SLIDE 158 Pituitary gland (hypophysis) This section has been stained to show the chromophils and chromophobes of the pars distalis. Identify the main areas at this low magnification. 1. 0 mm

SLIDE 158 Pituitary gland (hypophysis) This section has been stained to show the chromophils and chromophobes of the pars distalis. Identify the main areas at this low magnification. pars tuberalis infundibular stalk pars intermedia pars distalis pars nervosa This section shows a number of space artefacts, Probably produced during fixation of the tissue. The area indicated as hypophyseal cleft is much exaggerated and is shown better in section 159. hypophysial cleft 1. 0 mm

SLIDE 158 Pituitary gland (hypophysis) Pars distalis : The chromophils have stained well, the acidophils staining pink and the basophils staining deep pink to purple. The chromophobes remain poorly stained. 25 µm

SLIDE 151 Thyroid gland Whole section viewed under low power. 1. 0 mm

SLIDE 151 Thyroid gland Whole section viewed under low power. trachea thyroid gland lumen of trachea 1. 0 mm

SLIDE 151 Thyroid gland Note the different sized follicles and the connective tissue capsule surrounding the gland. Connective tissue septa or trabeculae divide the gland into lobes. 250 µm

SLIDE 151 Thyroid gland Note the different sized follicles and the connective tissue capsule surrounding the gland. Connective tissue septa or trabeculae divide the gland into lobes. connective tissue capsule thyroid follicles connective tissue septum blood vessels in capsule 250 µm

SLIDE 151 Thyroid gland Thyroid viewed at higher power. What substance fills each follicle? 100 µm

SLIDE 151 Thyroid gland Thyroid viewed at higher power. What substance fills each follicle? Colloid; a suspension of iodinated thyroglobulin. thyroid colloid the colloid fills the follicles space artefacts occur during histological fixation A : artefact thyroid follicles A 100 µm

SLIDE 151 Thyroid gland Thyroid viewed at higher power. What substance fills each follicle? Colloid; a suspension of iodinated thyroglobulin. What is its function? thyroid colloid the colloid fills the follicles space artefacts occur during histological fixation A : artefact thyroid follicles A 100 µm

SLIDE 151 Thyroid gland Thyroid viewed at higher power. What substance fills each follicle? Colloid; a suspension of iodinated thyroglobulin. What is its function? Thyroglobulin is the storage form of thyroid hormones T 3 and T 4. thyroid colloid the colloid fills the follicles space artefacts occur during histological fixation A : artefact thyroid follicles A 100 µm

SLIDE 151 Thyroid gland Thyroid viewed at high power. What changes would be evident in a thyroid follicle under TSH stimulation? 50 µm

SLIDE 151 Thyroid gland Thyroid viewed at high power. What changes would be evident in a thyroid follicle under TSH stimulation? The follicles would be smaller with less colloid. The cuboidal lining cells are taller, indicating active hormone synthesis and secretion. colloid space artefact cuboidal epithelium lining follicles 50 µm

SLIDE 151 Thyroid gland Where are ‘C’ cells located? 50 µm

SLIDE 151 Thyroid gland Where are ‘C’ cells located? C cells also called parafollicular cells are derived from the neural crest; they occur singly amongst the follicle cells or more usually are found in small groups between the follicles. C cells arrowed 50 µm

SLIDE 151 Thyroid gland What is the secretory product of C cells? 25 µm

SLIDE 151 Thyroid gland What is the secretory product of C cells? Calcitonin : Secreted in response to high levels of blood calcium. It lowers these levels by reducing the resorption of bone. thyroid colloid C : C cells C cuboidal follicular cells 25 µm

SLIDE 153 Parathyroid glands At low magnification note that these glands lie within the capsule of the thyroid. 1. 0 mm

SLIDE 153 Parathyroid glands At low magnification note that these glands lie within the capsule of the thyroid gland connective tissue capsule parathyroid 1. 0 mm

SLIDE 153 Parathyroid glands The parenchymal cells form cords and are highly vascularised. What is the main cell type present in this gland? 250 µm

SLIDE 153 Parathyroid glands The parenchymal cells form cords and are highly vascularised. What is the main cell type present in this gland? Principal cells (chief cells). thyroid cords of principal cells blood vessels capsule 250 µm

SLIDE 153 Parathyroid glands What do the principal cells produce? 100 µm

SLIDE 153 Parathyroid glands What do the principal cells produce? Parathyroid hormone (PTH). capsule cords of principal cells blood vessel 100 µm

SLIDE 153 Parathyroid glands What conditions would result in the release of this hormone? 50 µm

SLIDE 153 Parathyroid glands What conditions would result in the release of this hormone? Low blood calcium levels. Parathyroid hormone (PTH) raises blood calcium levels by increasing calcium absorption from the gut (diet) and from bone. It also decreases renal calcium excretion. active principal cells stain darkly, inactive cells are lighter staining. 50 µm

SLIDE 24 Pancreas rat (H and E stain) At low magnification identify and locate the Islets of Langerhans in the pancreas. 0. 5 mm

SLIDE 24 Pancreas rat (H and E stain) At low magnification identify and locate the Islets of Langerhans in the pancreas. i : islets of Langerhans pale pink staining areas (3 only marked) i i i exocrine pancreas 0. 5 mm

SLIDE 24 Pancreas rat (H and E stain) With Haematoxylin and eosin the acini of the exocrine pancreas stain darker, with the basal portions of the cells staining stronger with the haematoxylin. The islets of langerhans stain pale pink by comparison. Pancreas left lobe Pancreas right lobe ascending duodenum descending duodenum ▪ Organ in situ. Cadaver in left lateral recumbency. ▪ Identify also : jejunum & mesojejunum, liver, portal vein, diaphragm. 100 µm

SLIDE 24 Pancreas rat (H and E stain) With Haematoxylin and eosin the acini of the exocrine pancreas stain darker, with the basal portions of the cells staining stronger with the haematoxylin. The islets of langerhans stain pale pink by comparison. interlobular duct blood vessel pancreatic acini exocrine pancreas islet of Langerhans endocrine pancreas 100 µm

SLIDE 157 Pancreas (Gomori stain) The H & E stain showed the pale pink areas of islets clearly against the surrounding exocrine pancreas, but all cells in the islets were stained the same. The Gomori stain helps to differentiate between cell types in the islet. Cells are stained shades of pink, purple and blue. Pancreas – Sheep Organ in situ. Cadaver in left lateral recumbency L - Left lobe B - Body R - Right lobe Identify also: Sigmoid loop of duodenum, descending duodenum, ascending duodenum, right kidney, caudate process of liver, portal vein 250 µm

SLIDE 157 Pancreas (Gomori stain) The H & E stain showed the pale pink areas of islets clearly against the surrounding exocrine pancreas, but all cells in the islets were stained the same. The Gomori stain helps to differentiate between cell types in the islet. Cells are stained shades of pink, purple and blue. connective tissue capsule lobule Is Is : islets of Langerhans blood vessels adipocytes Is interlobular duct 250 µm

SLIDE 157 Pancreas (Gomori stain) What cell types are present in an islet and what do they secrete? 100 µm

SLIDE 157 Pancreas (Gomori stain) What cell types are present in an islet and what do they secrete? α cells : secrete glucagon. δ cells : secrete somatostatin. β cells : secrete insulin. F cells : pancreatic polypeptide. exocrine pancreas islet duct arteriole venule 100 µm

SLIDE 157 Pancreas (Gomori stain) How many cell types can be identified based on their histological staining? 50 µm

SLIDE 157 Pancreas (Gomori stain) How many cell types can be identified based on their histological staining? Purple staining β cells and pink staining α cells. Endothelial cells of capillaries. β red blood cells α α β capillary 50 µm

SLIDE 157 Pancreas (Gomori stain) Which islet hormone will increase glycogenolysis? α β 50 µm

SLIDE 157 Pancreas (Gomori stain) Which islet hormone will increase glycogenolysis? Glucagon. α β 50 µm

SLIDE 157 Pancreas (Gomori stain) Which islet hormone will increase glycogenolysis? Glucagon. In which major blood vessel are islet hormones carried from the pancreas? α β 50 µm

SLIDE 157 Pancreas (Gomori stain) Which islet hormone will increase glycogenolysis? Glucagon. In which major blood vessel are islet hormones carried from the pancreas? Hepatic portal vein. α β 50 µm

SLIDE 155 Adrenal gland Seen at low magnification, identify the zones of the adrenal gland : i). Zona glomerulosa. A : capsule. B : cortex. ii). Zona fasciculata. iii). Zona reticularis. C : medulla Sheep Adrenal Gland x/s ▪ Identify: capsule, cortex, medulla 1. 0 mm

SLIDE 155 Adrenal gland Seen at low magnification, identify the zones of the adrenal gland : i). Zona glomerulosa. A : capsule. B : cortex. ii). Zona fasciculata. iii). Zona reticularis. C : medulla capsule cortex medulla zona reticularis zona fasciculata zona glomerulosa 1. 0 mm

SLIDE 155 Adrenal gland At a slightly higher magnification the zona glomerulosa and zona fasciculata of the adrenal cortex. (In horses, cats and dogs an area called the zona intermedia can be identified between the glomerulosa and fasciculata). Dog Adrenal Gland x/s ▪ (with perirenal fat) ▪ Identify: cortex, medulla 250 µm

SLIDE 155 Adrenal gland At a slightly higher magnification the zona glomerulosa and zona fasciculata of the adrenal cortex. (In horses, cats and dogs an area called the zona intermedia can be identified between the glomerulosa and fasciculata). zona reticularis zona fasciculata zona glomerulosa capsule 250 µm

SLIDE 155 Adrenal gland Cortex. Zona Glomerulosa : The cells in the zona glomerulosa are arranged in clusters or arcs. 100 µm

SLIDE 155 Adrenal gland Cortex. Zona Glomerulosa : The cells in the zona glomerulosa are arranged in clusters or arcs. T : cortical trabeculae zona fasciculata zona glomerulosa T capsule (connective tissue) 100 µm

SLIDE 155 Adrenal gland Cortex. Zona Fasciculata : The zona fasciculata forms the widest layer in the adrenal cortex. 100 µm

SLIDE 155 Adrenal gland Cortex. Zona Fasciculata : The zona fasciculata forms the widest layer in the adrenal cortex. sinusoid zona fasciculata zona glomerulosa 100 µm

SLIDE 155 Adrenal gland Cortex. Zona Fasciculata : The cells in the zona fasciculata are arranged in radial cords, usually one cell thick. Cells are cuboidal to columnar. 50 µm

SLIDE 155 Adrenal gland Cortex. Zona Fasciculata : The cells in the zona fasciculata are arranged in radial cords, usually one cell thick. Cells are cuboidal to columnar. sinusoids 50 µm

SLIDE 155 Adrenal gland Cortex. Zona Reticularis : This is the inner zone of the cortex lying next to the adrenal medulla. 100 µm

SLIDE 155 Adrenal gland Cortex. Zona Reticularis : This is the inner zone of the cortex lying next to the adrenal medulla zona reticularis 100 µm

SLIDE 155 Adrenal gland Cortex. Zona Reticularis : The cells in the zona reticularis form irregular anastomosing cords surrounded by sinusoids. 50 µm

SLIDE 155 Adrenal gland Cortex. Zona Reticularis : The cells in the zona reticularis form irregular anastomosing cords surrounded by sinusoids irregular cords of cells 50 µm

SLIDE 155 Adrenal gland Medulla : The adrenal medulla consists of columnar or polyhedral cells in cords and clusters. These are called Chromaffin cells and have a neuroectodermal origin. 100 µm

SLIDE 155 Adrenal gland Medulla : The adrenal medulla consists of columnar or polyhedral cells in cords and clusters. These are called Chromaffin cells and have a neuroectodermal origin. adrenal medulla zona reticularis 100 µm

SLIDE 155 Adrenal glands What are the hormonal products of each of these zones? Zona glomerulosa : Zona fasciculata : Zona reticularis : Adrenal medulla :

SLIDE 155 Adrenal glands What are the hormonal products of each of these zones? Zona glomerulosa : Zona fasciculata : Zona reticularis : Adrenal medulla : aldosterone (acts mainly on kidney to regulate electrolyte and fluid balance).

SLIDE 155 Adrenal glands What are the hormonal products of each of these zones? Zona glomerulosa : aldosterone (acts mainly on kidney to regulate electrolyte and fluid balance). Zona fasciculata : cortisol (many metabolic effects). Zona reticularis : Adrenal medulla :

SLIDE 156 Adrenal gland cat (Sudan black stain) Stained with Sudan black for lipid. What are the lipid droplets? 1. 0 mm

SLIDE 156 Adrenal gland cat (Sudan black stain) Stained with Sudan black for lipid. What are the lipid droplets? Cholesterol esters. Lipid staining: The zona fasciculata is especially distinct and can readily be distinguished from the overlying zona glomerulosa and the underlying zona reticulosa. 1. 0 mm

SLIDE 156 Adrenal gland cat (Sudan black stain) Would the number of lipid droplets increase or decrease following stimulation with ACTH and why? 250 µm

SLIDE 156 Adrenal gland cat (Sudan black stain) Would the number of lipid droplets increase or decrease following stimulation with ACTH and why? Decrease, because they are made into steroids. capsule ZG : zona glomerulosa ZF : zona fasciculata ZR ZF ZG ZR : zona reticularis 250 µm

SLIDE 156 Adrenal gland cat (Sudan black stain) How is the release of catecholamines from the adrenal medulla regulated? capsule ZG : zona glomerulosa ZF : zona fasciculata ZR ZF ZG ZR : zona reticularis 250 µm

SLIDE 156 Adrenal gland cat (Sudan black stain) How is the release of catecholamines from the adrenal medulla regulated? By sympathetic innervation. capsule ZG : zona glomerulosa ZF : zona fasciculata ZR ZF ZG ZR : zona reticularis 250 µm

Lectures. Dr R Fowkes. Lectures. Dr C Wheeler-Jones. Second Year Histology. O 20. ENDOCRINES. J Bredl. 06 -09 -04. Gross Anatomy Correlates. Dr S Frean. Slides and Stains. Tanya Hopcroft. Compressed and updated. 2005/6/7. 2010