Endocrine System 内 分 泌 系 统

1. Endocrine System内 分 泌 系 统 Teacher: Wang Qiao Zhi 泸州医学院组胚教研室

2. Main contents： General Introduction Thyroid gland(甲状腺) Parathyroid gland (甲状旁腺) Adrenal gland（肾上腺） Hypophysis （垂体）

3. General Introduction • 1. Composition of Endocrine system Thyroid gland Parathyroid gland Adrenal gland Hypophysis Pineal body endocrine organs endocrine structures islets of Langerhans corpus luteum isolatedendocrine cells interstitial cells in the testis hilus cells in the ovary digestive tract

4. 2.    General structure • capsule: CT • parenchyma: endocrine cells are arranged in nests/clusters, or cords, or follicles. secrete hormones It is the most important method that we identify any endocrine glands in L.M. • interstitium: CT, rich in capillaries • There is no duct. （ductless glands）

6. 3. Contrast to exocrine glands Endocrine • Glands release hormones into blood or the extracellular matrix Exocrine • Secretory products are delivered to lumen via ducts Distance secretion：H into the caps, transported by the blood circulation to distant target cells paracrine secretion: H into the extracellular matrix.flow from cell to cell by diffusion.

7. 4. Hormones Hormones:Chemical messenger secreted into blood and carried to “target cells” where it alters activity. target cell:any cell that has a corresponding receptor for specific hormone Classes of Hormones：According to biochemical structure: Peptide Protein Amino acid analogs and derivatives nitrogenous-hormone Steroid hormone cholesterol derivatives

8. Hormone + Receptor

9. * nitrogenous-hormone secreting cell: • RER • Golgi • secretory granules

10. *steroid-hormone secreting cell: • SER • mitochondria: with lamellar or tubular cristae • lipid droplet: raw materials

11. Functions of Endocrine system : Secrete hormones that coordinate and direct activities of target cells/organs Regulates mood, growth ,development ,metabolism, sexual function, reproduction, blood pressure,etc Most systems are under combined control of endocrine and nervous systems • ES and NS = 2 main control systems of body

12. Thyroid gland ---largest endocrine gland, 15-40g ---two-lobes, connect to each other by isthmus

13. 1)General structure: ---capsule of LCT: insert into parenchyma to separate them into lobules ---parenchyma: follicles

14. thyroidfollicle（甲状腺滤泡） ---spherical Sac, 0.05-0.5mm 滤泡上皮细胞 ( follicular epithelial cell ) simple cuboidal epithelium 滤泡旁细胞（parafollicular cell） lumen： Colloid-iodinated thyroglobulin 碘化的甲状腺球蛋白 HE: eosinophilic, homogeneous structure

15. 胶质 ① Follicular epithelial cell ---structure: LM: • cuboidal: flattened(inactive) or columnar ( more active) • spherical centrally-located Nucleus • basophilic cytoplasm

17. EM: • microvilli • Golgi, secretory granules in the supranuclear area • RER, lysosome Function: synthesize and release thyroid hormones thyroxine(T4) triiodothyronine(T3)

18. hormonessynthesis ofprocesses: i.   synthesis of thyroglobulin ii.  Uptake of circulating iodide iii.  Iodination of thyroglobulin ⅳ.Release of thyroid hormones glycosylation Luminal surface is Many microvilli Basal surface rests on a thin basement membrane FENESTRATED CAPILLARIES run in close proximity to the basement membrane

20. Function of thyroid hormones: • increase the basal metabolism rate • promote the cell growth • raise body temperature • increase heart rate • play a role in fetal and neonatal development of CNS

21. Hyperthroidism (Overactive Thyroid) • Common symptoms : • shaking, increased nervousness, irritability • Rapid heart beat or palpitations • Feeling hot • Weight loss • Fatigue, feeling exhausted • More frequent bowel movements • Enlarged gland • eye symptoms, bulging of the eyes

22. Myxedema face Hypothyroidism (Underactive thyroid) • Fatigue or lack of energy • Weight gain • Feeling cold • Dry skin and hair • Heavy menstrual periods • Constipation • Slowed thinking

23. 呆小症/克汀病 Cretinism • Poor growth (height) • Neurological impairment Delayed bone maturation Thickened skin • Infertility Dementia face

24. 3)parafollicular cell ---single between follicular epithelial cell ---in small groups in the interstitial spaces outside the thyroid follicles ---structure:

25. LM: /ovoid, polygonal /larger /pale-stained /argyrophilic granules EM: /nitrogenous-hormone secreting cell feature /granules: contain calcitonin Function: promoting activity of osteoblast and suppressing the absorption of calcium in digestive tract and kidndy.

26. Parathyroids(甲状旁腺) Located on posterior surface of thyroid chief (principal) cells and oxyphil cells Parathyroid hormone (PTH) Stimulates Ca2+ release from bone Promotes intestinal absorption and renal tubular reabsorption of calcium

27. Parathyroids(甲状旁腺) Chief cells

28. Adrenal gland ---paired, situated on the upper poles of kidney.

29. Adrenal gland ---capsule: CT ---cortex: outer portion, derived from mesoderm ---medulla: inner portion, derived from neuroectoderm cortex

30. 1) adrenal cortex: ---constitutes 80-90% of total volume ---three zones: glomerulosa, fasciculata, reticularis

31. glomerulosa 15% of cortex volume fasciculata 78% reticularis 7% Cortex cells secret steroid-hormone.

32. ①zona glomerulosa: 球状带 Beneath the capsule LM: /small, low columnar or pyramidal cell /arranged into rounded or arched configuration /chromatin-dense nucleus ,acidophilic cytoplasm EM: /steroid-hormone secreting cell feature Function:mineralocorticoid-aldosterone (reabsorb Na+ and release K+)

33. 束状带 78% ②   zona fasciculate: LM: /large, polygonal or columnar cell / arranged into cords, perpendicularly to the surface / containing numerous lipid droplets, appear vacuolated

34. EM: /steroid-secreting cell feature /more lipid droplets Function: secret glucocorticoid-cortisol or corticosterone /promote protein and fat transfer into glucose /impair inflammatory /reduceimmune reaction

35. ③  zona reticularis: 球状带 7% LM: /polygonal, small cell /arranged into cord to form network /acidophilic cytoplasm EM: /steroid-secreting cell feature /less lipid droplet and more lipofuscin pigment Function: secret androgen(testosterone) and small amount of oestrogen

37. 2) Adrenal medulla ① medullary cell: LM: /polyhedral, large nests or short cords /weakly basophilic cytoplasm brownish granules- when fixed by bichromate-containing fixative This brownish colour is produced by a reaction between the chromium, hence the term chromaffin cells.

38. EM &Function /electron-dense granules: • adrenaline cell: 80% i.increase the heart rate ii.dilate BV • noradrenaline cell: 20% i.increase blood pressure ii.increase the flow speed of blood

39. central vein ② ganglial cell: polypolar neurons- large ③ central vein:

40. Cushing's Syndrome Reason: hypersecretion of glucocorticoid by the adrenal cortex • upper body obesity • round or moon-shaped face • increased fat around neck • thinning arms and legs • fragile and thin skin • acne • stretch marks on abdomen, thighs • bone and muscle weakness • severe fatigue • high blood sugar • irritability and anxiety • excessive hair growth in females

41. Pituitary gland (hypophysis) ovoid, flattened organ, 0.5g in weight, in pituitary fossa of sphenoid bone connects to the hypothalums through a stalk called the infundibulum.

42. anterior lobe Pituitary gland adenohypophysis neurohypophysis The pars nervosa and pars intermedia constitute posterior lobe.

43. embryologic origin Rathke's pouch Adenohypophysis derived from an outpocketing of the oral ectoderm, called Rathke's pouch oral cavity neurohypophysis derived from the downgrowth of the neuroectoderm of the floor of the third ventricle,called the infundibulum.

44. hypophysis:showing the three parts: pars distalis( ), pars intermedia( ) and pars nervosa(※).（ pig，H.E， ×40）

45. 1) The pars distalis The cells are arranged in clusters or cords that are separated by fenestrated sinusoidal capillaries.

46. according to their staining affinity 1) The pars distalis （1）chromophobe cell(嫌色细胞)： （2） chromophil cell (嗜色细胞)： a. acidophils(嗜酸性细胞) b. basophils(嗜碱性细胞) EM: chromophil are nitrogenous-hormone secreting cell

47. ① acidophil: 40% LM: • round, ovoid • Strong eosinophilic EM:According to size and appearance ofgranules • i.    somatotroph: • growth hormone(GH): promote the growth and metabolism of bone ii.mammotroph: prolactin(PRL): promote the growth and secreting of mammory gland after pregnancy.

48. 10% ②basophil: LM: • less, large cell • ovoid or polyhedral • basophilic cytoplasm

49. i.thyrotroph: -thyroid stimulating hormones(TSH) stimulates the growth of the thyroid follicular epithelial cells and the synthesis and release of thyroid hormones. • ii.    corticotroph: • -adrenocorticotropic hormone(ACTH) stimulates the cells of the zone fasciculata and reticularis of the adrenal cortex to synthesize and secrete glucocorticoids.

50. iii.Gonadotroph • -luteinizing hormone(LH): • -follicle stimulating hormone(FSH): • Female: ovulation and formation of corpus luteum, secretion • of progesterone • Male: interstitial cell-stimulating hormone(ICSH), regulate • the secretion of androgen by Leydig cell in testis Female: development of ovarian follicle Male: spermatogenesis in testis