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02. Pituitary and Hypothalamus I


Pituitary

  1. Master endocrine gland
  2. Small gland
  3. Situated at the base of the brain in the hypophyseal fossa
  4. Infundibulum pierces the diaphragma sellae to attach to the floor of the 3rd ventricle
Relations
image

Superiorly
  • Diaphragma sellae
  • Optic chiasma
  • Tuber cinerium
  • Infundibular recess
Lateral
  • Cavernous sinus
  • cranial nerves are damaged in lateral enlargement :3rd, 4th,5th & 6th cranial nerves can be damaged)
Inferior
  • Sphenoid sinus (change in shape due to pituitary lesions)
  • Hypophyseal fossa
  • Venous channels
  1. Neurohypophysis
  2. Adenohypophysis
image

Neurohypophysis
Adenohypophysis
Embriologically Diencephalon Ectodermal (Rathke’s pouch)
Morphologically Posterior lobe
(Continuous with the 3rd ventricle)
  • More GLIAL cells
Anterior lobe
(Separated from primitive oral cavity)
  • More EPITHELIAL cells
Functionally ADH, Oxytosin GH, ACTH, FSH, LH, TSH,
Prolactin
Blood supply Superior & inferior hypophyseal arteries Portal vessels (starts & ends with capillaries )
  • Carry hormone releasing factors from the hypothalamus
Veins drain to near by dural sinuses


Applied anatomy



Symptoms due to pressure effects
( Tumors)
Symptoms due to hormonal effects
  • Pressure on optic chiasma
  • Bitemporal hemianopia
  • Acromegaly (increased GH)
  • Hypothalamic syndrome
  • Cushing syndrome (decreased ACTH)
  • Enlarged sella tursica (pituitary fossa enlarged)
  • Prolactinoma (increased Prolactin secretion )
  • Pressure upon 3rd ventricle (increased ICP)
  • Hypopituitarism (less hormone secretion)



Hypothalamus



General features
Functions
Applied anatomy
Part of diencephalon
Forms the floor & the lateral wall of the 3rd ventricle
Endocrine control DI – Decreased ADH level
Head ganglion of the autonomic systems Neurosecretion Diencephalic autonomic epilepsy
  • Salivation
  • Sweating
  • Flushing
2 major nuclei
  • Supra optic
  • Para ventricular
Autonomic effects
  • Anterior – parasympathetic
  • Posterior – sympathetic
Hyper glycaemia
Regulation of food & water intake Sleep disturbances
Temperature regulation Obesity – Frolic’s syndrome
Sexual behavior & reproduction
Act as a biological clock
  • Controls the circadian rhythm of hormone secretion
Emotional control



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02. Pituitary and Hypothalamus I 02. Pituitary and Hypothalamus I Reviewed by Radiology Madeeasy on April 09, 2010 Rating: 5
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