Nucleus | Function | Effects of lesion |
Preoptic | Sexually dimorphic LHRH release | Irregular menstrual cycle and loss of libido |
Anterior | Heat loss centre vasodilation and inhibit shiver | Hyperthermia |
Posterior | Heat rise centre | Hypotermia |
Lateral | Hunger centre | Anorexia and emaciation |
Medial | Satiety centre | Obesity |
Mamillary body | Short term memory | Wernicke's encephalopathy |
Supraoptic | ADH secretion | Diabetes insipidus |
Suprachiasmatic | Circadian rhythms | disturb the sleep-waking cycle |
Paraventricular area | Oxytocin release | |
Preoptic and anterior (Caudal parts of the hypothalamus) | Control parasympathetic system | |
Posterior and lateral (Cranial parts of the hypothalamus) | Control sympathetic system | |
Lateral | Thirst centre (increase water intake) |
- Emotional Behaviour
- The hypothalamus has an important influence on emotions like fear, anger, and pleasure.
- Stimulation of
- Lateral areas of the hypothalamus produces sensations of pleasure,
- Medial areas produces pain or other unpleasant effects.
- Temperature regulation
- involves integration of
- Autonomic (vasodilatation/vasoconstriction),
- Musculoskeletal (panting/shivering)
- Endocrine responses (e.g., thyroxine secretion).
- The anterior hypothalamus constitutes a heat loss center, with stimulation causing vasodilatation and inhibition of shivering, resulting in hypothermia.
- The posterior hypothalamus is a heat conservation center causing vasoconstriction and shivering. Neurons in respond to both local warming of hypothalamic tissue as well as to warming of the skin.
- Neurons in both the septal and preoptic regions respond to abnormal increases in body temperature with antipyretic responses.
- Stress response
- Cortisol secretion to
- Mobilize energy stores
- Dec. Glycogen storage and inc. usage
- Improve cardiovascular tone
- Inc. heart rate
- Inc. BP
- Decrease immune response
- Dec. cytokine production → dec. inflammatory response
- Cardiovascular haemostasis
- Haemostasis of
- Blood volume
- BP
- HR
- Via secretion of ADH and Oxytocin from the paraventricular nucleus
- Thirst mechanism
- Fluid balance -ADH
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