2. Hypothalamus: introduction
• Below thalamus
• Forms lower lateral wall and floor of 3rd ventricle
• Each side:
preoptic, supraoptic, tuberal and mammillary
areas
• Many smaller nuclei, diverse functions.
3. Learning objectives
• Name the nuclei of hypothalamus.
• Name their afferent and efferent connections.
• Briefly describe the role of hypothalamus in regulation of:
1. autonomic nervous system and homeostasis
2. secretion of hormones of anterior pituitary
3. body temperature
4. food intake
5. water intake
• State the causes and consequences of disordered
hypothalamic function
12. Motivation and emotional behaviour
Principal outlet for effects of limbic system
Fear and rage
Reward and punishment areas
13. Regulation of body temperature
Heat gain Heat loss
Anterior hypothalamus
(exposure to heat)
Posterior hypothalamus
(exposure to cold)
Cutaneous vasodilatation
Sweating, hyperventilation
heat production
Cutaneous vasoconstriction
Release of CAs, TSH
activity, hunger
Shivering
14. Regulation of food intake
Lateral
feeding centre
Food intake
Ventromedial
satiety centre
Increase in
glucose
16. Hyperosmolarity Hypovolemia
Angiotensin II
Subfornical organ
Osmoreceptors
(supraoptic)
Thirst + ADH
Increased water intake Decreased urinary volume
Osmolarity restored Blood volume restored
Regulation of water balance
Preoptic area
17. Disorders/syndromes
Etiology: infection, vascular, tumors, compression.
• Narcolepsy: sleep disorder
• Endocrine: diabetes insipidus, sexual disorders.
• Lesion of VM satiety centre: obesity.
• Lesion of lateral feeding centre: emaciation.
• Temperature regulation.
18. Hypothalamus: summary
• Small area, many nuclei, diverse functions.
• Regulates cyclic phenomena: sleep-wake cycle.
• Controls autonomic functions.
• Neuro-endocrine integration.
• Regulates food and water intake.
• Regulates body temperature.
• Regulation of many functions: homeostasis.
• Disordered function:
infection, tumors, compression, vascular