Endocrine System Lecture PDF

ENDOCRINE GLANDS ENDOCRINE SYSTEM The endocrine system includes the endocrine glands and their hormones The function of the endocrine system is to secrete hormones into the bloodstream. Hormone: A Chemical messenger which targets a specific group of cells, in order to cause that grou...

ENDOCRINE GLANDS ENDOCRINE SYSTEM The endocrine system includes the endocrine glands and their hormones The function of the endocrine system is to secrete hormones into the bloodstream. Hormone: A Chemical messenger which targets a specific group of cells, in order to cause that group of cells do some activity or stop doing an activity. ENDOCRINE GLANDS HORMONES capillary proteins and glycoproteins small peptides secretory cells amino-acid derivatives steroids  DISTINGUISH DIFFERENT COMMUNICATION PATHWAYS AUTOCRINE: PARACRINE: CELL PRODUCES HORMONE CELL PRODUCES HORMONE THAT STIMULATES OR THAT STIMULATES OR INHIBITS ITSELF INHIBITS ITS NEIGHBOR JUXTACRINE: CELLS SIT SIDE BY SIDE. ONE HAS HORMONE ON SURFACE, THE OTHER HAS THE RECEPTOR. LOCATIONS OF THE MAJOR ENDOCRINE GLANDS.  PITUITARY GLAND (HYPOPHYSIS) It is about 1 cm in diameter It weighs 0.5 - 1 g  PITUITARY GLAND COMPONENTS (A) ADENOHYPOPHYSIS CEREBRI: 1- PARS DISTALIS (PARS ANTERIOR) 2- Pars Tuberalis 3- Pars Intermedia (B) NEUROHYPOPHYSIS CEREBRI: PARS NERVOSA ADENOHYPOPHYSIS CEREBRI  pars distalis capillary Acidophils basophil chromophobes  Pituitary gland: cells Adenohypophysis Neurohypophysis Axon Chromophils Chromophobes terminals Pituicytes with Herring’s bodies Acidophils Basophils (ADH, oxytocin) Somatotrophs Mammotrophs Thyrotrophes Gonadotrophs Corticotrophs (GH) (prolactin) (TSH) (FSH, LH) (ACTH)  PITUITARY GLAND (HYPOPHYSIS) (H+E): ADENOHYPOPHYSIS –PARS DISTALIS (ANTERIOR LOBE) chromophobes basophils acidophils sinuses chromophobes acidophil  TYREOTROPHS SOMATOTROPHS MAMMOTROPHS GONADOTROPHS CORTYCOTROPHS  GROWTH HORMONE OVERSECRETION of growth hormone: – GIANTISM IN CHILDHOOD and ACROMEGALY IN ADULTS (bones of face, hands and feet enlarge) UNDERSECRETION of growth hormone: – DWARFISM IN CHILDHOOD Too much growth hormone (STH) in childhood Acromegaly - too much growth hormone in adulthood  PARS INTERMEDIA PARS DISTALIS (ANTERIOR LOBE) PARS INTERMEDIA PARS NERVOSA In human this is remanant of Rathe’s pouch and mainly cosist of cysts filled with colloid PARS DISTALIS (ANTERIOR LOBE) PARS NERVOSA INFUNDIBULUM  HYPOTHALAMUS weight approx. 0.7g; diameter approx. 1 cm This is a small but important area in the center of the brain. It plays an important role in hormone production and helps to stimulate many important processes in the body and is located in the brain, between the pituitary gland and thalamus. The hypothalamus’ main role is to keep the body in homeostasis as much as possible. Homeostasis means a healthful, balanced bodily state. The body is always trying to achieve this balance. The hypothalamus acts as the connector between the endocrine and nervous systems. It plays a part in many essential functions of the body such as: body temperature; thirst; appetite and weight control; emotions; sleep cycles; sex drive; childbirth; blood pressure and heart rate; production of digestive juices; balancing bodily fluids. SUPRAOPIC NUCLEUS  NEUROHYPOPHYSIS PARS NERVOSA CONTENTS: 1- UNMYELINATED AXONS OF SECRETORY NEURONS situated in supraoptic & paraventricular nuclei (i.e. Axons of hypothalamo- hypophyseal tract). 2- FENESTRATED BLOOD CAPILLARIES FUNCTION STORAGE & RELEASE OF: a- VASOPRESSIN (ADH) b- OXYTOCIN  3. HERRING BODIES Are distentions of the axons in part nervosa. Representing accumulation of neurosecretory granules at axon terminals and along the length of the axons in part nervosa. 4. PITUICYTES Are glial-like cells in part nervosa. STRUCTURE: Have numerous cytoplasmic Processes. FUNCTIONS: Support the axons of the pars nervosa. No secretory or neuronal cells in pars nervosa. HERRING BODIES PITUICYTES NERVE FIBERS pars nervosa glial cell nuclei capillary endothelial cell nuclei  PINEAL GLAND weight approx. 0,2g; length 5-8 mm, width 3-5 mm  PINEALOCYTES INTERSTITIAL GLIAL CELLS PINEALOCYTES PINEALOCYTES CORPUS ARENACEUM (BRAIN SAND) THYROID Weighs about 25 g, size and shape variable. Built with two lobes connected by a necking  THYROID GLAND (H+E) SEPTUM CONNECTIVE  colloid blood vessels  (PRINCIPAL cells) Function: Synthesis of thyroid hormones (T4 & T3). T3 – triiodothyronine; T4 - thyroxine (CLEAR CELLS) (C-CELLS) follicle parafollicular cells colloid  THYROID GLAND- PARAFOLLICULAR CELL (C cell) (H+E)  GRAVES DISEASE 80-90% of all hyperthyroidism One of most common autoimmune diseases Mostly women Antibody that acts like TSH Gland is diffusely enlarged & smooth GRAVES' DISEASE  THYROIDITIS Inflammation of thyroid Mostly chronic-autoimmune Presents as goiter ENDEMIC GOITER  Iodine deficiency in your diet results in GOITER (enlargement of thyroid gland) THYROID PARATHYROID  PARATHYROID GLANDS (H+E) oxyphil cells principal (chief) cells  ADRENAL GLAND weight approx. 18g, weight about 4 g.  ADRENAL GLANDS (H+E) adrenal medulla adrenal cortex capsule  capsule adrenal cortex adrenal medulla 15% of the cortical volume 80% of the cortical volume 5% to 7% of the cortical volume water and electrolyte balance  CAPSULE zona glomerulosa zona fasciculata zona reticularis BLOOD VESSELS CHROMAFFIN CELLS ADDISON DISEASE Before After Cushing’s Syndrome DNES cells secreting serotonin or certain other amine derivatives demonstrate amine precursor uptake and decarboxylation and are often referred to acronymically as APUD cells.