1. Depart. Of Histology & Embryology
Endocrine system
Depart. Of Histology & Embryology
Luo Bin
罗 彬

2. Why can you grow up?

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

4. Endocrine glands
Thyroid gland
Adrenal glands
Pituitary gland

5. General description Components
Endocrine glands Endocrine tissues （ Pancreas islet ） Endocrine cells
Function
Endocrine system
produce
Hormones
target organs
Act on
target cells
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. Thyroid gland follicles
Follicular epithelial cells EM:
microvilli
RER, Golgi apparatus
secretory granules
lysosome, mitochondria
endocytotic vesicles
Function:
synthesize and release thyroid hormones
thyroxine (T4)
triiodothyronine (T3)
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. Pathological state hypothyroidism exophthalmic goiter myxoedema
In adults, thyroid hormone
overproduction
underproduction
myxoedema
hyperthyroidism
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
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 restless hyperactivity
★ diarrhoea

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

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 球状带 束状带 网状带 Zona glomerulosa 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. appear vacuolated(formy)-empty
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. Zona reticularis 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 ---Function: secrete adrenaline and noradrenaline EM
electron-dense granules
adrenaline cell: 80% 肾上腺素细胞
noradrenaline cell: 20% 去甲肾上腺细胞
Adr. cell
Noradr. cell
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. Excessive adrenal secretion of glucocorticoid hormones
Pathological state
Excessive adrenal secretion of glucocorticoid hormones
Cushing’s syndrome

27. Pituitary gland capsule: CT adenohypophysis pars intermedia
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 Classification: Chromophobes Chromophils Acidophils
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. thyroid stimulating hormone(TSH) follicle stimulating hormone(FSH)
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
basophil
thyrotrope
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. Pathological state
Titan
Jack Sprat

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

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

35. Pas intermedia Pas tuberalis Secrete gonadotropin. Structure:
chromophobe cells
basophils
be arranged into cords/follicles.
Function:
Secrete melanocyte-stimulating hormone (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. Blood supply (Hypophyseal portal system)
Superior hypophyseal artery
(Primary plexus)capillaries
Hypophyseal portal vein
（Secondary plexus）
capillaries
Hypophyseal vein

39. Relationship between hypothalamus and adenohypophysis
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 位 置 被膜下 中层 深层，近髓质 厚 度 最薄 最厚 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
毛细血管
球间血窦
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
分泌激素
盐皮质激素
糖皮质激素
雄激素及少量糖皮质激素 作用
调节水盐代谢（排钾保钠）
糖异生、应激、抗炎、抑制免疫等
蛋白质代谢
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!