The pituitary gland develops from an evagination of ectoderm called Rathke's pouch and a neuroectodermal diverticulum from the hypothalamus. The anterior pituitary develops from Rathke's pouch while the posterior pituitary develops from the diverticulum. Possible anomalies include ectopic posterior pituitary, pharyngeal hypophysis, agenesis of the pituitary gland, duplication, and craniopharyngioma tumor. The pineal gland develops from a diverticulum of the diencephalon. The adrenal glands develop from coelomic epithelium for the cortex and neural crest cells for the medulla. The thyroid gland is the first endocrine gland to develop

1. DEVELOPMENT
OF
ENDOCRINE SYSTEM

2. PITUITARY GLAND

3. PITUITARY GLAND
Chronological age:
Middle of 3th week of IUL
Germ layer:
Surface Adenohypophysis
Ectoderm
Neuro Neurohypophysis
Site:
A) Stomodeum
B) Buccopharyngeal membrane

4. PITUITARY GLAND
Sources:
A) Surface ectoderm part (Rathke’s pouch)
- Pars Distalis
- Pars Tuberalis
- Pars Intermedia
B) Neuro ectoderm part (Hypopyseal stalk)
- Infudibulum
- Pars Posterior (Neurohypophysis)
- Median eminance

6. Adenohypophysis
 Develops from an evagination of ectoderm lining
the roof of primitive oral cavity called rathke’s
pouch
 Rathke’s pouch develops in third week of IUL.
 Later this pouch is cut off from the primitive mouth
stomodeum.

9. Walls of Rathke’s pouch
a) Anterior wall proliferates
extensively to form pars
anterior.
b) Posterior wall remains thin and
forms pars intermedia
c) Cleft of pouch persist
hypophyseal cleft.
Small extension of pars
anterior grows upward to form
pars tuberalis.

11. Neurohypophysis

12. Neurohypophysis
Develops from an evagination of neurectoderm
of hypothalamus/floor of third ventricle.
Neurectodermal diverticulum from the floor of
third ventricle.
Ectodermal pouch from the roof of stomodeum
fuse with each other to form hypophysis
cerebri.

13. PITUITARY GLAND

14. Possible congenital anomalies
• Ectopic posterior pituitary
• Pharyngeal hypophysis
• Agenesis/Hypogenesis of pituitary gland
• Duplication of pituitary gland
• Congenital tumor of the gland
(Craniopharyngioma)

15. 1) Ectopic posterior pituitary
Absent normal posterior pituitary
Bright spot within the sella with ectopic bright
signal at another site (such as the median
eminence) on a weighted magnetic resonance
Development:
Incomplete caudal extension of the diencephalon
during embryogenesis

17. Effect:
Pituitary dwarfism
Lack of growth hormone

18. 2) Pharyngeal hypophysis
Development:
-A remnant of the stalk of the hypophysial
diverticulum in the roof of the oropharynx
Pharyngeal
hypophysis

19. • Ectopic pituitary tissue is found attached to the
roof of the mouth.
• It is caused by failure of separation of Rathke's
pouch from the roof of the mouth.

20. 3) Agenesis/
Hypogenesis of pituitary gland

21. Effect:
Absence of the gland is incompatible with life,
i.e. it leads to death of the infant
Hypogenesis of pituitary gland: It leads to
panhypopituitarism
(is a condition of inadequate or absent production of the
anterior pituitary hormones.)

22. 4) Duplication of pituitary gland
Development:
-Fewer (40 cases since 1880)
-A rare craniofacial developmental anomaly
occurring during blastogenesis.

23. • *Several mechanisms have been proposed for
DPG:
– partial twinning,
– prenatal teratogen exposure,
– extreme presentation of the median cleft face
syndrome
– splitting of the notochord during blastogenesis
• DPG is associated with various clinical
findings that represent a continuum of defects
in blastogenesis

24. 5) Congenital tumor of the gland
(Craniopharyngioma)
Development:
A tumor arises from a remnant of Rathke's
pouch. *

26. Effect:
• Increasing the intracranial pressure;
hydrocephalus
• Disrupting the function of the pituitary gland
• Damaging the optic nerve

27. PINEAL GLAND

28. PINEAL GLAND

29. PINEAL GLAND
Source: Small diverticulum arising from the
roof of the diencephalon
Pineal gland is made up of modified neuroglial
cells called pinealocytes.
Process of development:
Diverticulum form
Initially hollow mass
Later, becomes solid structure

32. ADRENAL GLANDS

33. ADRENAL GLANDS

34. ADRENAL GLAND
Sources:
A) Cortex  Coelomic epithelium
- Foetal cortex  Larger acidophilic cells
- Definitive cortex  Smaller cells
B) Medulla  Neural crest cells
- Similar to postganglionic sympathetic
neurons

38. ADRENAL
GLANDS
DEVELOPMENT

40. THYROID GLAND

43. THYROID GLAND
Chronological age:
3th week of IUL (1st endocrine organ to develop)
Germ layer:
Endodermal diverticulum (Thyroglossal duct)
Site:
Floor of the pharynx [below & behind the
tuberculum impar of developing tongue]

44. Sources:
Median thyroid diverticulum
GLANDULAR TISSUE:
Thyroid gland compose of
A) Follicular cells  Endodermal origin
B) Para follicular cells  Ultimo branchial body
THYROID GLAND

52. Fate of thyroglossal duct:
Anomalies:
1) Lingual thyroid
2) Retro sternal thyroid
3) Thyroglossal cyst
THYROID GLAND

53. THYROID GLAND