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The hypothalamus II


Connections of the hypothalamus with the pituitary gland

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A. Hypothalamo – hypophyseal tract (Vasopressin & Oxytocin are send to the posterior lobe of the pituitary gland)
B. Hypophyseal – portal system (Carry releasing & releasing inhibitory hormones to the anterior lobe of the pituitary gland)



Hypothalamic hormones & their effects on the pituitary




Hypothalamic regulatory hormone
Anterior pituitary hormone
Action
  • GHRH
GH
Stimulates linear growth in epiphyseal cartilage
  • GHIH (Somatostatin)
Reduce the production of GH
Reduces linear growth in epiphyseal cartilage
  • PRH
Prolactin (LTH)
Stimulates lactogenesis
  • PIH (Prolactin inhibiting hormone)
Reduce the production of Prolactin
Reduces lactogenesis
  • CRH (Corticotropin – releasing hormone )
ACTH (Adrenocorticotropic hormone)
Stimulates the adrenal glands to produce corticosteroids & sex  hormones
  • TRH (Thyrotropin – releasing hormone)
TSH
Stimulates the thyroid gland to produce thyroxin
  • LHRH (Luteinizing hormone – releasing hormone)
LH (Luteinizing hormone) & FSH (Follicular stimulating hormone)
Stimulates ovarian follicles and production of estrogen & progesterone


Functions of the main hypothalamic nuclei




Hypothalamic nuclei
Function
  • Supra optic
Synthesizes vasopressin 
  • Para ventricular
Synthesizes Oxytocin
  • Preoptic & anterior
Control parasympathetic system
  • Posterior & lateral
Control sympathetic system
  • Anterior
Response to heat
  • Posterior
Response to cold
  • Lateral
Increase water intake (Thirst center)
Initiate eating & increase food intake (Hunger center)
  • Medial
Inhibit eating & reduce food intake (Satiety center)
  • Supra chiasmatic
Controls circadian rhythm
The hypothalamus II The hypothalamus II Reviewed by Radiology Madeeasy on August 05, 2010 Rating: 5
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