The hypothalamus II

Connections of the hypothalamus with the pituitary gland A. Hypothalamo – hypophyseal tract (Vasopressin & Oxytocin are send to t...

Connections of the hypothalamus with the pituitary gland



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