The Endocrine System document provides an overview of several endocrine glands and their functions, including: - The pituitary gland (hypophysis), located at the base of the skull, which is divided into the adenohypophysis and neurohypophysis. The adenohypophysis contains cell types that secrete hormones like growth hormone, prolactin, TSH, ACTH, and gonadotropins. - The suprarenal (adrenal) glands, located over the kidneys, which are divided into the cortex and medulla. The cortex secretes mineralocorticoids, glucocorticoids, and androgens to regulate electrolyte

1. The Endocrine System
Dr. Samar AskerDr. Samar Asker
Asst.Professor of HistologyAsst.Professor of Histology
Faculty of MedicineFaculty of Medicine

2. 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)

3. THE PITUITARY GLAND
(HYPOPHYSIS CEREBRI(

4. Base of the skull in (sella
turcica).
Connected to hypothalamus
by infundibular stalk
Formed 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

5. ADENOHYPOPHYSIS

6. Pars Distalis
Cells arranged in
groups or branching
cords separated by
fenestrated capillaries.
They are classified into:
Chromophobes
Chromophils.

7. 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.

8. Chromophils
(48%)
Have affinity to
stain.
Classified into:
Acidophils (37%)
Basophils(11%).

9. Acidophils :
Medium sized cells ()
Chromophobes &
basophils
2 types
Somatotrophs
Mammotrophs

10. 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

12. Basophils:
Largest cells
Basophilic granules
Three types:
Thyrotrophs
Corticotrophs
Gonadotrophs

13. Cell type Thyrotrophs Corticotrophs
FSH LH
Hormone
& its
action
TSH
T3 T4
ACTH
MSH
Endorphin
Lipotrophic
factor
FSH LH
Shape Rounded
with central
rounded
nucleus
oval with
eccentric
nucleus
Rounded
with
rounded
nucleus
Gonadotrophs

14. Pars Nervosa
Secrete no
hormones.
Contain :
1 Pituicytes.‑
2 Nerve fibres no‑
nerve cells.
3 Herring bodies‑
4 Fenestrated‑
capillaries.

15. 2 glands, lying over
the upper border of
the kidney.
THE SUPRARENAL
GLANDS

16. 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.

17. The parenchyma: is
divided into cortex and
medulla.

18. 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.

19. Zona Fasciculata:
Widest zone, cells in a radial in
direction
polyhedral 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 nuclei
Their cytoplasm is vacuolated so
called spongiocytes.

20. Function:
Secrete gluco corticoids (Cortisol)‑ which
controles protein & carbohydrate metabolism
under control of ACTH
Anti inflammatory & immunosuppressive
effects.

21. 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