endocrine glands
TRANSCRIPT
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The Endocrine System
Dr. Samar AskerDr. Samar AskerAsst.Professor of HistologyAsst.Professor of Histology
Faculty of MedicineFaculty of Medicine
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Glands: pituitary, suprarenal, thyroid, parathyroid, pineal body.
Masses of cells: islets of Langerhans, testis ovary, thymus………
Cells scatered all over the body ;APUD cells (Amine Precursor Uptake Decarboxylase)
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THE PITUITARY GLAND (HYPOPHYSIS CEREBRI)
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Base of the skull in (sella turcica).
Connected to hypothalamus by infundibular stalkFormed of :Adenohypophysis :develops from oral ectoderm as upward growth from the roof of oral cavity forming Rathke's pouch.
Neurohypophysis: develops as neuroectoderm as downward growth from the floor of diencephalon
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ADENOHYPOPHYSIS
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Pars DistalisCells arranged in groups or branching cords separated by fenestrated capillaries.
They are classified into:
Chromophobes
Chromophils.
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Chromophobes(52%):Small with pale cytoplasm & mild affinity to stains
Some are granular & may secrete hormones.
Some are non granular & considered as stem cells or exhausted Chromophils.
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Chromophils(48%)
Have affinity to stain.
Classified into:
Acidophils (37%)
Basophils(11%).
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Acidophils :
Medium sized cells () Chromophobes & basophils
2 types
Somatotrophs
Mammotrophs
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Somatotrophs • secrete the growth H.
• Secretion gigantism
acromegally Secretion dwarfism• Spherical cells with central
rounded nucleus & acidophilic granules
• +ve reaction with
orange G.
Mammotrophs • Secrete prolactin milk sec.
• Oval cells with Oval nucleus & acidophilic granules
• +ve reaction with carmine
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Basophils:
Largest cells Basophilic granulesThree types:
ThyrotrophsCorticotrophsGonadotrophs
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Cell typeThyrotrophs Corticotrophs
FSHLHHormone & its action
TSHT3 T4
ACTHMSHEndorphinLipotrophic factor
FSHLH
Shape Rounded with central rounded
nucleus
oval with eccentric nucleus
Rounded with rounded nucleus
Gonadotrophs
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Pars Nervosa
Secrete no hormones.
Contain :
1‑Pituicytes.
2‑ Nerve fibres no nerve cells.
3‑ Herring bodies
4‑ Fenestrated capillaries.
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2 glands, lying over the upper border of the kidney.
THE SUPRARENAL GLANDS
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The Stroma:Capsule :
thick dense fibrous CT covered with adipose CT.
Trabeculae: arise from the capsule and extend in the cortex dividing it into compartments
Reticular fibres.
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The parenchyma: is divided into cortex and
medulla.
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The Cortex:
Zona glomerulosa:Narrow zone under the capsule. The cells are columnar arranged in arched groups surrounded by fenestrated capillaries basal oval nuclei and pale cytoplasm .Function: secretemineralo corticoid (aldosterone) ‑ which
regulate electrolyte & water balance) controlled by angiotensinogen II.
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Zona Fasciculata:Widest zone, cells in a radial in directionpolyhedral cells arranged in narrow straight cords one or two cells wide separated by straight fenestrated capillaries.Central rounded pale vesicular nuclei, some cells have 2 nucleiTheir cytoplasm is vacuolated so called spongiocytes.
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Function: Secrete gluco corticoids (Cortisol) ‑ which
controles protein & carbohydrate metabolism under control of ACTH
Anti inflammatory & immunosuppressive effects.
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Zona reticularis:Deepest zone.polyhedral cells arranged
in branching and anastomosing cords
separated by fenestrated blood sinusoids.
Central rounded nuclei acidophilic cytoplasm
Function: secrete androgen and small amounts of gluco corticoids‑ under control of ACTH.
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