Depart. Of Histology & Embryology
Luo Bin
罗 彬
Why can you
grow up?
General description
• Components
Endocrine glands
Endocrine tissues （ Pancreas islet ）
Endocrine cells
• Function
Endocrine system
target organs
produce
Hormones
Act on
target cells
What is hormone？
Hormones are molecules that function in the body as chemical signals.
Endocrine
glands

Thyroid gland

Adrenal glands

Pituitary gland
General description
• Components
Endocrine glands
Endocrine tissues （ Pancreas islet ）
Endocrine cells
• Function
Endocrine system
target organs
produce
Hormones
Act on
target cells
What is hormone？
Hormones are molecules that function in the body as chemical signals.
Hormones secretion
Special secreting forms

Autocrine （自分泌）

Paracrine （旁分泌）
common features
⑴ Ductless
⑵ Endocrine cells arrange into nests, cords, clusters or follicles
⑶ Rich in capillaries
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
Thyroid gland
• General structure
--- capsule : L.C.T
forming septa
--- parenchyma:
lobules
follicles
interstitium: CT
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.
Thyroid gland follicles
Follicular epithelial cells EM:
•
microvilli
•
RER, Golgi apparatus
secretory granules
•
lysosome, mitochondria
endocytotic vesicles
Function:
synthesize and release thyroid hormones
According to the structures of follicular epithelial cells,
四碘甲状腺原氨酸
thyroxine
can you(T4)
illustrate their
functions?
triiodothyronine (T3) 三碘甲状腺原氨酸
What is the secretory process?
i. Synthesis of thyroglobulin
ii. Iodination of thyroglobulin
iii. Release of thyroid hormones
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.
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
Pathological state
In adults, thyroid hormone
overproduction
underproduction
Thyroid hormone deficiency slows
A consequence of an increase in
body processes:
hyperthyroidism
body’s
metabolism:
hypo
thyroidism
Clinical features:
Clinical features:
★
dry, puffy skin
★
feeling hot
★
inability to keep warm
★
increased sweating
★
weight gain
★
weight loss, with poximal
★
a slow heart rate
★
loss of energy and appetite
★
★
constipation
★ anxiety and restless hyperactivity
muscle weakness
★
exophthalmic goiter
rapaid heart rate
diarrhoea
myxoedema
Pathological state
Hypothyroidism present at birth:
Mental retardation
Short stature
Coarse facial features
Protruding tongue
Umbilical hernia
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
Parathyroid gland
• Structure capsule
parenchyma
glandular cells
stroma
chief cells
oxyphil cells
• Function
synthesize parathyroid
hormone (PTH)
make blood calcium
Adrenal gland
---capsule: CT
---cortex: yellow,
derived from mesoderm
内胚层
---medulla: reddishbrown, derived from
neural ectoderm
神经外胚层
Adrenal gland cortex
Zona glomerulosa
球状带
Zona glomerulosa
Zona fasciculata
束状带
Zona fasciculata
Zona reticularis
网状带
Zona reticularis
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
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
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
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
Adrenal medulla
EM
electron-dense granules
Noradr.
cell
adrenaline cell: 80% 肾上腺素细胞
i. heart rate
ii. dilate blood vessel
Adr. cell
noradrenaline cell: 20% 去甲肾上腺细胞
i. blood pressure
ii. the flow speed of blood
---Function:
secrete adrenaline and noradrenaline
secrete some polypeptides(galanin, neuropeptide Y, enkephalin)
Pathological state
Excessive adrenal secretion of glucocorticoid
hormones
Cushing’s syndrome
Pituitary gland
capsule: CT
adenohypophysis
腺垂体
pars distalis
anterior lobe
远侧部
前叶
pars tuberalis
结节部
pars intermedia
中间部
pars nervosa
neurohypophysis
神经垂体
神经部
infundibular stalk
漏斗柄
median eminence
正中隆起
posterior lobe
后叶
Pituitary gland
Pituitary gland
Infundibular
Pars distalis
Pars intermedia
Pars nervosa
Pas distalis
Glandular cells are arranged in nests
Rich in capillaries around the cells
Classification:
Chromophobes
Acidophils
Chromophils
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
Tropic hormones of pas distalis
cell
type
secreting hormone
somatotrope
somatotropic hormone(STH)
or growth hormone(GH)
生长激素细胞
acidophil
mammotrope
催乳激素细胞
thyrotrope
lactogenic hormone(LTH)
or prolactin(PRL)
thyroid stimulating hormone(TSH)
促甲状腺激素细胞
corticotrope
basophil
adrenocorticotropic hormone(ACTH)
促肾上腺皮质激素细胞
gonadotrope
follicle stimulating hormone(FSH)
luteinizing hormone(LH)
促性腺激素细胞 interstitial cell-stimulating hormone(ICSH)---male
Pathological state
Titan
Pathological state
growth hormone in kids
deficient
Dwarfism
too much
Gigantism
Pathological state
Too much growth hormone occurs in adults
Acromegaly 肢端肥大症
Protruding jaw
Broaden lower face
Enlarged hands
Pas intermedia
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.
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
Neurohypophysis
Herring bodies:
Neurosecretory granules accumulate in the dilated portions of
the axons near their terminals.
LM: acidophilic, irregular structure
Blood supply (Hypophyseal portal system)
Superior hypophyseal artery
(Primary plexus)capillaries
Hypophyseal portal vein
（Secondary plexus）
capillaries
Hypophyseal vein
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
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
78％
7％
体积比
15％
细胞排列
球状
毛细血管
球间血窦
细胞大小
较小
纵行的单或双行细胞索
细胞短索吻合成网
索间纵行血窦
网间血窦
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
受调节
肾素－血管紧张素系统
电镜结构
较典型
ACTH
典型的类固醇激素细胞的
超微结构
蛋白质代谢
ACTH
较典型