Chapter 12
Endocrine System
1,Components:
---small gland or endocrine cell,islet of
pancreasand corpus luteum
---endocrinegland:
Thyroid gland
Parathyroid gland
Adrenal gland
Pituitarygland(hypophysis)
Pinealbody
2,General structure
---capsule:CT
---parenchyma,endocrine cells arranged
into nest,cord,cluster or follicle,secrete
hormones
---interstitium:CT,rich in capillaries
* According to hormones
---nitrogenous-hormone secreting cell:
RER
Golgi
secretory granules
---steroid-hormone secreting cell:
SER
mitochondria,with tubular-vesicular cristae
lipid droplet,raw materials
3,Thyroid gland
---largestendocrinegland,15-40g
---two-lobes,connect to each other by
isthmus
1) General structure:
---capsule of LCT,insert into parenchyma
to separate them into lobules
---parenchyma:lobules
follicles
interstitium:CT
2) follicle:
---spherical,0.02-0.9mm
---epi + colloid
① Epithelium:
simplecuboidalepi
---structure:
LM:
cuboidal,flattened(inactive) or
columnar( more active)
basophiliccytoplasm
sphericalcentrally-locatedN
EM:
microvilli
RER,Golgi,secretory granules
lysosome,endocytotic vesicles
---function,synthesize and release thyroid
hormones
thyroxine(T4)
triiodothyronine(T3)
a,processes:
i,synthesis of thyroglobulin
ii,Iodination of thyroglobulin
iii,Release of thyroid hormones
b,functionof thyroid hormones
increasethe basal metabolismrate
promotethe cell growth
raisebody temperature
increaseheart rate
play a role in foetal and neonatal
developmentof CNS
② Colloid:iodinatedthyroglobulin
HE,eosinophilic,homogeneousstructure
3) parafollicular cell
---single between follicular cell
---in small groups in interstitial tissue
---structure:
LM:
/ovoid,polygonal
/larger
/pale-stained,eosinophilic
/argyrophilic granules
EM:
/nitrogenous-hormone
secreting cell feature
/granules,contain calcitonin
---function:
i,secret calcitonin to promote activity of
osteoblast and suppressing the absorption of
Ca++ in gastrointestinal tract and renal tubule
ii,secret calcitonin gene related peptide,
CGRP(act upon heart and small BV) and
somatostatin
4,Adrenal gland
---paired,situated on the upper poles of
kidney
---capsule:CT
---cortex:yellow,derived from mesoderm
---medulla,reddish-brown,derived from
neuroectoderm
1) adrenal cortex:
---constitutes80-90% of total volume
---three zones
① zona glomerulosa,5-10% of cortex volume
---structure:
LM:
/small,low columnar or polygonal cell
/arranged into nest or cluster
/deep stained
EM:
/steroid-hormonesecretingcell feature
/scatteredlipiddroplets
---function,mineralocorticoid-aldosterone
(reabsorbNa+ and releaseK+)
② zona fasciculate:
78%
---structure:
LM:
/large,polygonal or columnarcell
/arrangedinto cords
/appearvacuolated(formy)-empty
EM:
/steroid-secreting cell feature
/more lipid droplets
---function,secret glucocorticoid-cortisol or
corticosterone
/promote protein and fat transfer into
glucose
/impair immune reactive
③ zona reticularis:7%
---structure:
LM:
/polygonal(hedral),small cell
/arrangedinto cord to form network
/acidophiliccytoplasm
EM:
/steroid-secretingcell feature
/less lipid droplet and more lipofuscin
pigment
---function,secret androgen(testosterone)
and small amount of oestrogen
2) Adrenal medulla
① medullary cell:
chromaffin cell
---structure:
LM:
/polyhedral,cord
/brownish cytoplasm granules- when fixed by
bichromate-containing fixative
EM:
/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
Function:
i,secrete adrenaline and noradrenaline
ii,secrete some polypeptides(galanin,
neuropeptide Y,enkephalin)
② ganglial cell,polypolar neurons- large,2-3 in
groups
③ central vein
4,Pituitary gland
---ovoid,flattened organ,0.5X1X1cm,0.5g in
weight,in pituitary fossa of sphenoid bone
---capsule,CT
---adenohypophysis:
the pars distalis
the pars intermedia
the par tuberalis
---neurohypophysis:
the pars nervosa
infundibular stalk
1) The pars distalis
---cell,nest or cord-nitrogenous-hormone
secretingcell feature
---CT,rich in sinusoids
① acidophil,40%
LM:
round,ovoid
eosinophilic g
EM,According to granules
i,somatotroph:
-filled with round,electron-dense granules
-350nm
-somatotropic hormone(STH) or growth
hormone(GH),promote the growth and
metabolism of bone
ii,mammotroph:
-less,largestgranules
-600-700nm
-lactogenic hormone(LTH) or
prolactin(PR),promote the growth and
secretingof mammory gland
② basophil:
LM:
less,large cell
ovoidor polygonal
basophilicgranules
EM,accordingto granules
i,thyrotroph:
-less,round,smallestgranules
-150-200 nm,peripheral distributed
-thyroid stimulatinghormone(TSH)
ii,corticotroph:
-round,less,differentelectrondensity
-200-250nm,under plasmalemma
-adrenocorticotropichormone(ACTH)
-lipotropin,or lipotrophichormone(LPH)
iii,gonadotroph
-medium-sized,round granules
-200-300 nm
-follicle stimulating hormone(FSH):
Female,development of ovarian follicle
Male,spermatogenesis in testis
-luteinizing hormone(LH):
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
③ chromophobe cell
---structure:
LM:
/more,small,pale
/no clear boundary
EM,less granules
Function:
i,degranulatedcell
ii,under-developmentcell
3) The pars intermedia
---structure:
/chromophobecell
/basophil
/follicle:simplecuboidalepi,+ colloid
*basophil,melanotroph-melanocyte
stimulatinghormone(MSH)
4) Neurohypophysis
a.unmyelinated NF,axons of hypothalamus
cells
*hypothalamus:neuroendocrinecell
supraopticnucleus
paraventricularnucleus
secrete,antidiuretic hormone (ADH)
(vasopressin) increasing reabsorption of water
in renal tubule and causing the constriction of
arterioles to increase blood pressure
*Herring bodies:
LM,acidophilic,irregular structure
EM,axon where dilated portion with secreting
granules accumulate in
b,pituicyte:special glial cell
irregular with processes
cytoplasmcontain pigmentgranules
function:supportand nurish NF
c,capillaries(sinusoid)
5) Relationship between hypothalamus and
adenohypophysis,and hypophyseal portal
system
---arcuate nucleus of hypothalamus:
/neuroendocrine cell:
secrete releasing hormone(RH)-
GRH,PRH,TRH,GnRH,CRH,MSRH
secrete release inhibition hirmone(RIH)-SOM,
PIH,MSIH
their axons end in infundibular stalk and
release hormones into primary capillaries
---hypophyseal portal system:
Superior hypophyseal arteries(arisig from the
cerebral arterial circle)→primary capillary
plexus(infundibular stalk) →hypophyseal
portal veins→secondary capillary
plexus(the pars distalis) →vein
sinusoids(small vein)
6,diffuse neuroendocrine system,DNES
---scattered single endocrine cells
/synthesize and secrete amine-amine
precursor uptake and decarboxylation cell,
APUD cell
/also secrete peptide
/secretions are secreted by neurons-so called
DNES
---components:
/cells of hypothalamus and hypophysis
/endocrine cells of digestive tract,respiratory
system,pancreas and so on
/parafollicular cell of thyroid gland and
medullary cell of adrenal gland
Endocrine System
1,Components:
---small gland or endocrine cell,islet of
pancreasand corpus luteum
---endocrinegland:
Thyroid gland
Parathyroid gland
Adrenal gland
Pituitarygland(hypophysis)
Pinealbody
2,General structure
---capsule:CT
---parenchyma,endocrine cells arranged
into nest,cord,cluster or follicle,secrete
hormones
---interstitium:CT,rich in capillaries
* According to hormones
---nitrogenous-hormone secreting cell:
RER
Golgi
secretory granules
---steroid-hormone secreting cell:
SER
mitochondria,with tubular-vesicular cristae
lipid droplet,raw materials
3,Thyroid gland
---largestendocrinegland,15-40g
---two-lobes,connect to each other by
isthmus
1) General structure:
---capsule of LCT,insert into parenchyma
to separate them into lobules
---parenchyma:lobules
follicles
interstitium:CT
2) follicle:
---spherical,0.02-0.9mm
---epi + colloid
① Epithelium:
simplecuboidalepi
---structure:
LM:
cuboidal,flattened(inactive) or
columnar( more active)
basophiliccytoplasm
sphericalcentrally-locatedN
EM:
microvilli
RER,Golgi,secretory granules
lysosome,endocytotic vesicles
---function,synthesize and release thyroid
hormones
thyroxine(T4)
triiodothyronine(T3)
a,processes:
i,synthesis of thyroglobulin
ii,Iodination of thyroglobulin
iii,Release of thyroid hormones
b,functionof thyroid hormones
increasethe basal metabolismrate
promotethe cell growth
raisebody temperature
increaseheart rate
play a role in foetal and neonatal
developmentof CNS
② Colloid:iodinatedthyroglobulin
HE,eosinophilic,homogeneousstructure
3) parafollicular cell
---single between follicular cell
---in small groups in interstitial tissue
---structure:
LM:
/ovoid,polygonal
/larger
/pale-stained,eosinophilic
/argyrophilic granules
EM:
/nitrogenous-hormone
secreting cell feature
/granules,contain calcitonin
---function:
i,secret calcitonin to promote activity of
osteoblast and suppressing the absorption of
Ca++ in gastrointestinal tract and renal tubule
ii,secret calcitonin gene related peptide,
CGRP(act upon heart and small BV) and
somatostatin
4,Adrenal gland
---paired,situated on the upper poles of
kidney
---capsule:CT
---cortex:yellow,derived from mesoderm
---medulla,reddish-brown,derived from
neuroectoderm
1) adrenal cortex:
---constitutes80-90% of total volume
---three zones
① zona glomerulosa,5-10% of cortex volume
---structure:
LM:
/small,low columnar or polygonal cell
/arranged into nest or cluster
/deep stained
EM:
/steroid-hormonesecretingcell feature
/scatteredlipiddroplets
---function,mineralocorticoid-aldosterone
(reabsorbNa+ and releaseK+)
② zona fasciculate:
78%
---structure:
LM:
/large,polygonal or columnarcell
/arrangedinto cords
/appearvacuolated(formy)-empty
EM:
/steroid-secreting cell feature
/more lipid droplets
---function,secret glucocorticoid-cortisol or
corticosterone
/promote protein and fat transfer into
glucose
/impair immune reactive
③ zona reticularis:7%
---structure:
LM:
/polygonal(hedral),small cell
/arrangedinto cord to form network
/acidophiliccytoplasm
EM:
/steroid-secretingcell feature
/less lipid droplet and more lipofuscin
pigment
---function,secret androgen(testosterone)
and small amount of oestrogen
2) Adrenal medulla
① medullary cell:
chromaffin cell
---structure:
LM:
/polyhedral,cord
/brownish cytoplasm granules- when fixed by
bichromate-containing fixative
EM:
/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
Function:
i,secrete adrenaline and noradrenaline
ii,secrete some polypeptides(galanin,
neuropeptide Y,enkephalin)
② ganglial cell,polypolar neurons- large,2-3 in
groups
③ central vein
4,Pituitary gland
---ovoid,flattened organ,0.5X1X1cm,0.5g in
weight,in pituitary fossa of sphenoid bone
---capsule,CT
---adenohypophysis:
the pars distalis
the pars intermedia
the par tuberalis
---neurohypophysis:
the pars nervosa
infundibular stalk
1) The pars distalis
---cell,nest or cord-nitrogenous-hormone
secretingcell feature
---CT,rich in sinusoids
① acidophil,40%
LM:
round,ovoid
eosinophilic g
EM,According to granules
i,somatotroph:
-filled with round,electron-dense granules
-350nm
-somatotropic hormone(STH) or growth
hormone(GH),promote the growth and
metabolism of bone
ii,mammotroph:
-less,largestgranules
-600-700nm
-lactogenic hormone(LTH) or
prolactin(PR),promote the growth and
secretingof mammory gland
② basophil:
LM:
less,large cell
ovoidor polygonal
basophilicgranules
EM,accordingto granules
i,thyrotroph:
-less,round,smallestgranules
-150-200 nm,peripheral distributed
-thyroid stimulatinghormone(TSH)
ii,corticotroph:
-round,less,differentelectrondensity
-200-250nm,under plasmalemma
-adrenocorticotropichormone(ACTH)
-lipotropin,or lipotrophichormone(LPH)
iii,gonadotroph
-medium-sized,round granules
-200-300 nm
-follicle stimulating hormone(FSH):
Female,development of ovarian follicle
Male,spermatogenesis in testis
-luteinizing hormone(LH):
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
③ chromophobe cell
---structure:
LM:
/more,small,pale
/no clear boundary
EM,less granules
Function:
i,degranulatedcell
ii,under-developmentcell
3) The pars intermedia
---structure:
/chromophobecell
/basophil
/follicle:simplecuboidalepi,+ colloid
*basophil,melanotroph-melanocyte
stimulatinghormone(MSH)
4) Neurohypophysis
a.unmyelinated NF,axons of hypothalamus
cells
*hypothalamus:neuroendocrinecell
supraopticnucleus
paraventricularnucleus
secrete,antidiuretic hormone (ADH)
(vasopressin) increasing reabsorption of water
in renal tubule and causing the constriction of
arterioles to increase blood pressure
*Herring bodies:
LM,acidophilic,irregular structure
EM,axon where dilated portion with secreting
granules accumulate in
b,pituicyte:special glial cell
irregular with processes
cytoplasmcontain pigmentgranules
function:supportand nurish NF
c,capillaries(sinusoid)
5) Relationship between hypothalamus and
adenohypophysis,and hypophyseal portal
system
---arcuate nucleus of hypothalamus:
/neuroendocrine cell:
secrete releasing hormone(RH)-
GRH,PRH,TRH,GnRH,CRH,MSRH
secrete release inhibition hirmone(RIH)-SOM,
PIH,MSIH
their axons end in infundibular stalk and
release hormones into primary capillaries
---hypophyseal portal system:
Superior hypophyseal arteries(arisig from the
cerebral arterial circle)→primary capillary
plexus(infundibular stalk) →hypophyseal
portal veins→secondary capillary
plexus(the pars distalis) →vein
sinusoids(small vein)
6,diffuse neuroendocrine system,DNES
---scattered single endocrine cells
/synthesize and secrete amine-amine
precursor uptake and decarboxylation cell,
APUD cell
/also secrete peptide
/secretions are secreted by neurons-so called
DNES
---components:
/cells of hypothalamus and hypophysis
/endocrine cells of digestive tract,respiratory
system,pancreas and so on
/parafollicular cell of thyroid gland and
medullary cell of adrenal gland
