Is a group of glands that regulate physiological functions by releasing hormones into the bloodstream The Endocrine System Is the way by which a cell exerts its effects on another cell or on itself ID: 781423
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Slide1
A. Prof. Dr.
Emad
Ghanem
Slide2Is a group of glands that regulate physiological functions by releasing hormones into the
bloodstream.
The Endocrine System
Slide3Is
the way by which a cell exerts its effects on another cell ( or on itself
)IntracrineAutocrineJuxtacrineParacrine Endocrine
Intercellular signaling
Slide4Slide5Slide6Slide7Juxtacrine
Slide8Slide9TARGET ORGAN
The organs or tissues that are activated by released hormones are called
target organs or tissues.
The cells in the target organ/tissue have appropriate
receptors
, which are able to recognize and respond to specific hormones.
Slide10ENDOCRINE SYSTEM
Endocrine Glands
Clusters of Endocrine C
ells
Isolated
Endocrine
C
ells
Slide11Endocrine glands
Pituitary
Adrenal
Thyroid
Parathyroid
Pineal
Slide12Clusters of Endocrine Cells
Islets of
Langerhans in the PancreasJuxtaglomerulr apparatus in kidney
Corpus luteum in ovary
Interstitial cells of
Leyding
in testis
Placental
lactogen
secreting cells in placenta
Chorionic gonadotropin secreting cells in placenta
Slide13Isolated Endocrine Cells
DNES
APUDIn the Epithelium of the R.S &GITExample : G-cells in stomach secrete gastrin
Slide14Hormone
A chemical
substance produced in the body that controls and regulates the activity of certain cells or organs
Slide15Steroid Hormones (are lipids)
Adrenal cortex & sex hormones
(Estrogen, Testosterone, Cortisone, Aldosterone) Peptide Hormones Pituitary & parathyroid hormones(ACTH,TSH,FSH, GH , Prolactin, PTH)Amine Hormones Adrenal medulla & thyroid hormones(Adrenaline & Noradrenaline, T3 &
T4)
Slide16ADRENAL (SUPRARENAL) GLANDS
Slide17Capsule
Cortex
Medulla
Slide18Capsule
A M
A C
Slide19The AC & AM are 2 organs with distinct
Origins
Functions
Morphology
That become united during embryonic development
They arise from different embryonic germ layers:
The AC arises from
mesoderm
and
The AM derived from the
neural crest
Slide20G F R
Slide21Slide22Slide23Slide24Blood Supply
CORTICAL
CAPSULAR
MEDULLARY
ZG
ZF
AM
ZR
Slide25ADRENAL CORTEX
Zona Glomerulosa
(15 %)
closely packed, rounded or arched cords of columnar or pyramidal cells surrounded by many capillaries
Zona
Fasciculata
(75 %)
long cords of large polyhedral cells, 1 or 2 cells thick, separated by fenestrated sinusoidal capillaries.
spongyocytes
.
Zona
Reticularis
(10%)
smaller cells disposed in a network of irregular cords interwoven with wide capillaries.
ALL cortical cells contain and secret lipid hormones
Which are not membrane bound BUT APPEAR AS LIPID DROPLETS in EM and rounded vacuoles as seen by LM .
these cells have numerous, large spherical mitochondria (as seen by EM) .
Slide26Cortical Hormones
Z.G
Z.F
Z.R
Mineralocorticoid
(
Aldosterone
)
Glucocorticoids
(
Cortisol
)
Dehydroepiandrosterone
(DHEA)
Slide27Fetal Adrenal Cortex
Size > adult
CS x 2 adultProvisional cortex (
80%)
Principal function: secretion of DHEA which is converted in the placenta to active estrogens (and androgens), which mostly enter the maternal circulation.
Important part of a
fetoplacental
unit
which affects both endocrine systems during pregnancy but whose physiological significance remains largely unclear.
Slide28Cortex
Medulla
Provisional Cortex
Slide29Adrenal Medulla
Slide30Large, pale-staining polyhedral cells arranged in cords or clumps + sinusoidal capillaries
Chromaffin
cells (stained by chrome salts): modified sympathetic postganglionic neurons, lacking axons and dendrites and specialized as secretory cells.Unlike cells of the cortex, chromaffin cells contain electron-dense(dark)granules which are membrane bound , as seen by EM, for hormone storage and secretion. Catecholamines: epinephrine (adrenalin) or norepinephrine (
noradrenaline
)
.
Catecholamines
are bound to proteins called
chromogranins
.
the adrenal medulla also contains large scattered
ganglionic
cells of un known function.
Slide31Catecholamines
About 80% is
epinephrine (adrenaline) , nor epinephrine (nor adrenaline) and encephalin.
A & NA
are released to the blood in large quantities during intense and sudden emotional reactions, such as fear , and produce:
Vasoconstriction especially of skin, increased blood pressure,
inceased
in heart rate,
broncho
diletation
and metabolic effects such as elevated blood glucose .
These effects facilitate various defensive reactions to this stress type (the
fight-or-flight response
).
___ encephalin produces emotional changes ,reduces pain.
Slide32Slide33CLINICAL CORRELATION
Slide34LONG TERM TREATMENT
WITH
CORTICOSTEROID
Slide35Slide36Pheochromocytomas
Slide37Adrenocortical
disorders
Hyperfunctional
Hypofunctional
Slide38Z.G
Z.F
Z.R
Mineralocorticoid
(
Aldosterone
)
Glucocorticoids
(
Cortisol
)
Dehydroepiandrosterone
(DHEA)
Hyperfunctional
Conn’s Syndrome
Cushing’s Syndrome
Precocious
Puperty
(short stature)
Virilization
(after puberty)
Slide39Slide40DIFFUSE NEUROENDOCRINE SYSTEM
Names:
DNESGastro-Entero-Pancreatic (GEP) endocrine cells. Enterochromaffin cells
Argentaffin
APUD (amine precursor uptake and
decarboxylation
)
Slide41