Hypothalamus and its function

2. HYPOTHALAMUS
• Latin word
• Hypo- below
• Thalamus – room or chamber
• Diffuse nuclear mass below
thalamus
• A small cone-shaped structure,
it projects downward, ending in
the pituitary stalk.

5. HYPOTHALAMIC NUCLEI
• Supraoptic nucleus  Synthesize Vasopressin (ADH)
• Suprachiasmatic N  Control Circadian rhythm
• Para-ventricular N  Synthesize Oxytocin
 Punishment center
• Pre-optic & anterior N  Parasympathetic control
• Posterior & lateral N  Sympathetic control
 Rage center
• Anterior hypothalamic N  Response to heat
• Posterior hypothalamic N  Response to cold

6. HYPOTHALAMIC NUCLEI
• Lateral hypothalamic N  Punishment center
 Hunger center
 Thirst center
• Ventro-medial hypothalamic N  Satiety center
 Reward center

8. • Hypothalamus send output signals into three directions:
1. Downward to reticular areas of mesencephalons, pons and
medulla  Peripheral nerves
2. Upward to higher areas of diencephalon and cerebrum
3. To hypothalamic infundibulum  control anterior & posterior
pituitary gland

9. FUNCTION
• Vegetative function
• Endocrine control function
• Behavioral control function

10. VEGETATIVE FUNCTION
1. Cardiovascular regulation:
• Stimulation of posterior and lateral hypothalamus  increase
arterial pressure and heart rate
• Stimulation of preoptic area  decrease arterial pressure and
heart rate

11. VEGETATIVE FUNCTION
2. Regulation of body temperature:
• Increase in temperature  stimulate temperature-sensitive
neuron in anterior hypothalamus  causing heat loss
• Decrease in temperature  stimulate temperature-sensitive
neuron in posterior hypothalamus  heat gain center

12. VEGETATIVE & ENDOCRINE FUNCTION
3. Regulation of body water:
1. Thirst center activation  lateral hypothalamus
2. Excretion of water  supraoptic nucleus

13. VEGETATIVE & ENDOCRINE FUNCTION
4. Regulation of uterine contractility & milk ejection from
breasts:
• Stimulation of Paraventricular nuclei causes neuronal cells to
secrete oxytocin

14. ENDOCRINE FUNCTION
• The most important functions of the hypothalamus is to link
the nervous system to the endocrine system via the pituitary
gland.
• Neurohormones  hypothalamic-releasing hormones 
stimulate or inhibit the secretion of pituitary hormones

15. REGULATION OF HORMONAL SECRETION
Higher centres
Hypothalamus
Pituitary
Hormone
Pituitary hormone
Releasing hormone
Long feedback
Loop
eg. Thyroxine,
Cortisol
Short feedback
Loop
eg. LH, ACTH,
GH
Target gland

17. HYPOTHALAMIC HORMONES
• CRH: Corticotrophin releasing hormone (ACTH)
• TRH: Thyrotrophin releasing hormone
• GHRH: GH releasing hormone
• GnRH: Gonadotrophin (LH, FSH) releasing hormone
• Dopamine: Prolactin inhibition
• Vasopressin
• Oxytocin

19. BEHAVIORAL FUNCTION
• Para-ventricular N Punishment center
• Lateral hypothalamic N
• Posterior & lateral N  Rage center
• Ventro-medial hypothalamic N  Reward center

20. RAGE
• Emotional pattern that causes excessive stimulation of
punishment center in Posterior nucleus of hypothalamus.
• Inhibited by cerebral cortex

21. SHAM RAGE
• Generalized sympathetic over activity
• Loss of inhibitory effect of cerebral cortex
• Effects:
• Tachycardia
• Increase BP
• Pupillary dilatation
• Struggling movements

22. HOW HYPOGLYCEMIA PRODUCES HUNGER
• Satiety center contain Insulin bound glucoreceptors
• In case of hypoglycemia they are not saturated properly
• Activate feeding center
• Person feels hunger

23. Thank You