Depart. Of Histology & Embryology

1. Depart. Of Histology & Embryology Endocrine system LuoBin 罗 彬

2. Why can you grow up?

3. target organs Endocrine system produce Hormones Act on target cells General description • Components Endocrine glands Endocrine tissues （ Pancreas islet ）Endocrine cells • Function What is hormone？ Hormones are molecules that function in the body as chemical signals.

4. Endocrine glands • Thyroid gland • Adrenal glands • Pituitary gland

5. target organs Endocrine system produce Hormones Act on target cells General description • Components Endocrine glands Endocrine tissues （ Pancreas islet ） Endocrine cells • Function What is hormone？ Hormones are molecules that function in the body as chemical signals.

6. Hormones secretion Special secreting forms • Autocrine （自分泌） • Paracrine （旁分泌）

7. common features ⑴ Ductless ⑵ Endocrine cells arrange into nests, cords, clusters or follicles ⑶ Rich in capillaries

8. Two types of endocrine cells Steroid-hormone secreting cell 类固醇激素分泌细胞 Nitrogenous-hormone secreting cell 含氮激素分泌细胞

9. Thyroid gland • General structure ---capsule : L.C.T forming septa --- parenchyma: lobules follicles interstitium: CT

10. Thyroid gland follicles Constitution: Follicle: Colloid is surrounded by a single layer epithelium. 1. Epithelium: Simple squamous (hypoactive), cuboidal or columnar (hyperactive), depending upon the functional status. 2. Colloid: Homogeneous secretion of epithelium. Acidophilic and PAS (+). Contains iodinated thyroglobulin.

11. Function: synthesize and release thyroid hormones thyroxine (T4) triiodothyronine (T3) Thyroid gland follicles Follicular epithelial cells EM: • microvilli • RER, Golgi apparatus secretory granules • lysosome, mitochondria endocytotic vesicles According to the structures of follicular epithelial cells, can you illustrate their functions? 四碘甲状腺原氨酸 三碘甲状腺原氨酸

12. What is the secretory process? i.   Synthesis of thyroglobulin ii.  Iodination of thyroglobulin iii. Release of thyroid hormones

13. Formation of T3 & T4: a. AA→ RER→ thyroglobulin → (Gogi, glycosylated→(G,secreting granules) → colloid. b. Iodide → (iodide pump) → iodide oxidation in cytoplasm → colloid → bound to tyrosine residues of thyroglobulin → iodated thyroglobulin.

14. c. iodated thyroglobulin → (TSH, microvilli) → endocytic vesicles →LYS → T3 & T4. Function of T3, T4: a. elevate the basal metabolic rate. b. influence the body growth and nervous system development during fetal life. Modulation of T3, T4 secretion: hypothalamus-pituitary-thyroid axis

15. In adults, thyroid hormone A consequence of an increase in body’s metabolism: Clinical features: ★ feeling hot ★ increased sweating ★ weight loss, with poximal muscle weakness ★ rapaid heart rate ★ anxiety and restlesshyperactivity ★ diarrhoea Thyroid hormone deficiency slows body processes: Clinical features: ★ dry, puffy skin ★ inability to keep warm ★ weight gain ★ a slow heart rate ★ loss of energy and appetite ★ constipation overproduction underproduction hyperthyroidism hypothyroidism exophthalmic goiter myxoedema Pathological state

16. Pathological state Hypothyroidism present at birth: Mental retardation Short stature Coarse facial features Protruding tongue Umbilical hernia

17. Parafollicular cell ---single between follicular cells ---in small groups in interstitial tissue Also called calcitonin cell / C cell LM: • ovoid, polygonal • larger • pale-stained: eosinophilic • argyrophilic granules Function: synthesize and release calcitonin, make blood calcium

18. chief cells glandular cells oxyphil cells stroma Parathyroid gland • Structure capsule parenchyma • Function synthesize parathyroid hormone (PTH) make blood calcium

19. Adrenal gland ---capsule: CT ---cortex: yellow, derived from mesoderm ---medulla: reddish-brown, derived from neural ectoderm 内胚层 神经外胚层

20. Adrenal gland cortex Zona glomerulosa Zona glomerulosa 球状带 Zona fasciculata 束状带 Zona fasciculata Zona reticularis 网状带 Zona reticularis

21. Zona glomerulosa 15% of cortex volume ---Structure: LM cells: small, low columnar or polygonal be arranged into nests or clusters nuclei: deep stained, round cytoplasm: light basophilic ---Function: secrete mineralocorticoid ( eg. aldosterone) 盐皮质激素 醛固酮 regulate electrolyte and water balance

22. Zona fasciculata About 78% of cortex volume ---Structure: LM cells : large，clear margin be arranged in straight cords cytoplasm: light staining appear vacuolated(formy)-empty ---Function: secrete glucocorticosteroid盐皮质激素 (e.g cortisol、corticosterone) and androgen雄激素(less) regulate carbohydrate, protein and lipid metabolism influence immune response

23. Zonareticularis 7% of cortex volume ---Structure: LM cells: polyhedral and small; be arranged in irregular anastomosing cords cytoplasm: acidophilic ---Function: secret androgen(testosterone) and small amount of oestrogen 雌激素

24. Adrenal medulla ---Structure: medullary cell ( chromaffin cell ) : LM: cells: polyhedral, be arranged in nests or short cords cytoplasm: weakly basophilic, brownish granules- when fixed by bichromate-containing fixative. central vein ganglial cells: multipolar neurons large, 2~3 in groups

25. Adrenal medulla Noradr. cell Adr. cell EM electron-dense granules adrenaline cell: 80% 肾上腺素细胞 noradrenaline cell: 20% 去甲肾上腺细胞 i.  heart rate ii. dilate blood vessel i.  blood pressure ii. the flow speed of blood ---Function: secrete adrenaline and noradrenaline secrete some polypeptides(galanin, neuropeptide Y, enkephalin)

26. Pathological state Excessive adrenal secretion of glucocorticoid hormones Cushing’s syndrome

27. Pituitary gland capsule: CT pars distalis pars tuberalis pars intermedia anterior lobe adenohypophysis neurohypophysis 远侧部 前叶 结节部 腺垂体 posterior lobe 中间部 后叶 pars nervosa infundibular stalk median eminence 神经部 神经垂体 漏斗柄 正中隆起

28. Pituitary gland

29. Pituitary gland Infundibular Pars intermedia Pars distalis Pars nervosa

30. Pas distalis Glandular cells are arranged in nests Rich in capillaries around the cells Classification: Chromophobes Chromophils Acidophils Basophils A --- Acidophil round or oval , eosinophilic stainning B --- Basophil less, large cell, ovoid or polygonal basophilic granules C --- Chromophobe more, small, pale, no clear boundary

31. Tropic hormones of pas distalis cell type secreting hormone acidophil somatotropic hormone(STH) or growth hormone(GH) somatotrope 生长激素细胞 mammotrope lactogenic hormone(LTH) or prolactin(PRL) 催乳激素细胞 thyrotrope basophil thyroid stimulating hormone(TSH) 促甲状腺激素细胞 corticotrope adrenocorticotropic hormone(ACTH) 促肾上腺皮质激素细胞 follicle stimulating hormone(FSH) luteinizing hormone(LH) interstitial cell-stimulating hormone(ICSH)---male gonadotrope 促性腺激素细胞

32. Titan Jack Sprat Pathological state

33. Pathological state Gigantism growth hormone in kids deficient too much Dwarfism

34. Pathological state Acromegaly 肢端肥大症 Too much growth hormone occurs in adults Protruding jaw Broaden lower face Enlarged hands

35. Pas intermedia Structure: chromophobe cells basophils be arranged into cords/follicles. Function: Secrete melanocyte-stimulatinghormone (MSH) 黑素细胞刺激素 Pas tuberalis Secrete gonadotropin.

36. Neurohypophysis Pars nervosa Components • Pituicytes ( glial cells) • Capillaries (fenestrated) • Unmyelinated nerve fibers Function: Store and release oxytocin and antidiuretic hormone (ADH) 催产素 抗利尿激素

37. Neurohypophysis Herring bodies: Neurosecretory granules accumulate in the dilated portions of the axons near their terminals. LM: acidophilic, irregular structure

38. Superior hypophyseal artery (Primary plexus)capillaries Hypophyseal portal vein （Secondary plexus） capillaries Hypophyseal vein Blood supply (Hypophyseal portal system)

39. Relationship between hypothalamus andadenohypophysis Arcuate nucleus of hypothalamus (neuroendocrine cell): • secrete releasing hormones (RH) -GRH, PRH, TRH, GnRH, CRH, MSRH • secrete release inhibiting hormones (RIH) -SOM, PIH, MSIH • their axons end in infundibular stalk and release hormones into primary capillaries network of hypophyseal portal circulation • positive and negative feedback

42. 肾上腺皮质三带的比较 球状带 束状带 网状带 被膜下 位 置 中层 深层，近髓质 最薄 最厚 厚 度 较薄 体积比 15％ 78％ 7％ 细胞排列 球状 纵行的单或双行细胞索 细胞短索吻合成网 球间血窦 毛细血管 索间纵行血窦 网间血窦 细胞大小 较小 大 小 形 状 矮柱状或椎形 多边形 多边形 核 核小色深 核大圆色浅 核小色较深 胞 质 少量脂滴 大量脂滴 少量脂滴，脂褐素 糖皮质激素 分泌激素 盐皮质激素 雄激素及少量糖皮质激素 蛋白质代谢 作用 调节水盐代谢（排钾保钠） 糖异生、应激、抗炎、抑制免疫等 ACTH 受调节 肾素－血管紧张素系统 ACTH 较典型 电镜结构 较典型 典型的类固醇激素细胞的超微结构

43. Thank you!