Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Hypothalamus

5,950 views

Published on

Published in: Education

Hypothalamus

  1. 1. HYPOTHALAMUS Dr SaadiyahDepartment of Physiology DIMC
  2. 2. PROSENCEPHLON (Forebrain)TELENCEPHALON DIENCEPHHALON THALAMUS HYPOTHALAMUS EPITHALAMUS
  3. 3. HYPOTHALAMUS• Located inferior to thalamus• Very small size; few cubic centimeters• Comprises less than 1% of human brain• Almost every part of ANS & CNS communicate with it• Act on three major systems: ANS, Endocrine & limbic system• An integrative center essential for survival & reproduction of organism
  4. 4. Regulates:• Blood pressure• Heart rate• Electrolyte composition• Body temperature• Body water• Feeding• Endocrine hormone secretion by anterior pituitary• Uterine contractility• Milk ejaction• Reproduction• Emergency responses to stress
  5. 5. • Divided into following regions:Anterior (Supraoptic)PreopticMiddle (tuberal)Posterior (mammillary)
  6. 6. Anterior (supraoptic)Region:•Superior tooptic chiasm•Paraventricular,Supraoptic,Anterior &Suprachiasmaticnuclei
  7. 7. Anterior (supraoptic)Region:• Vasopressin & oxytocin• Circadian rhythm• Temperature
  8. 8. Preoptic Area:• Anterior to supraoptic region• Medial & lateral preoptic nuclei• Regulates certain autonomic activies
  9. 9. Preoptic area:• Temperature• Blood pressure• Reproduction• Drinking• Feeding• Hormone (thyrotropin)
  10. 10. Middle (tuberal) region:• Dorsomedial, Ventromedial, Lateral & Arcuate nuclei• Infundibulum connects it with pituitary gland
  11. 11. Middle (tuberal) region:• Satiety center (VMN)• Hunger center (Lat)• Thirst center (Lat)• Neuroendocrine control• GI stimulation
  12. 12. Posterior ( mammillary) Region:•Most posteriorpart ofhypothalamus•Adjacent to midbrain•Mammillarybodies &posterior nuclei
  13. 13. • Temperature control• Relay station for sense of smell• Feeding reflex
  14. 14. Mammillary bodies:• Two small rounded projections.• Are component of limbic system• Limbic system: Emotional BrainRing of structures on the inner border of cerebrumPlays primary role in range of emotions including pain, pleasure, affection & anger.Also involved in olfaction & memory
  15. 15. MEDIAL ZONE• Preoptic (part)• Anterior• Suprachiasmatic (part)• Parventricular• Dorsomedial• Ventromedial• Arcuate• Posterior
  16. 16. LATERAL ZONE• Preoptic (part)• Suprachiasmatic (part)• Supraoptic• Lateral
  17. 17. Cardiovascular Regulation• Stimulation in posterior & lateral hypothalamus INC arterial pressure & heart rate• Stimulation in preoptic area DEC arterial pressure & heart rate
  18. 18. BODY TEMP. REGULATION• Anterior portion of hypothalamus especially Preoptic area is concerned• Inc in temp of blood flowing through this area inc activity of temp sensitive neurons
  19. 19. • Fall in body temp below set point • Temp monitoring nerve cells + • Temp control center +• Skeletal muscles & other effector organs • Inc heat production • Inc in body temp to set point
  20. 20. • Infection • Macrophages • Prostaglandins • Inc Hypothalmic set point • Inc heat producton, Dec heat loss• Inc body temp to new set point=fever
  21. 21. BODY WATER REGULATION• Two ways:• Water drinking (Thirst center= Lateral hypothalamus)• Excretion (ADH=Supraoptic)
  22. 22. FEEDING REGULATION• Hunger center is located in lateral hypothalmic area• Damage to this area causes loss of desire for food• Satiety center is loated in ventromedial nuclei• Damage to this area causes voracious appetite
  23. 23. ENDOCRINE REGULATION• Thyrotropin releasing hormone• Corticotropin releasing hormone• Growth hormone releasing hormone• Growth hormone inhibitory hormone (somatostatin)• Gonadotropin releasing hormone• Dopamine/ Prolactin inhibiting factor• ADH• Oxytocin
  24. 24. Hypothalamic Control of the Anterior Pituitary• Hypothalamus neurons synthesize releasing and inhibiting hormones.• Hormones are transported to axon endings of median eminence.• Hormones secreted into the hypothalamo- hypophyseal portal system regulate the secretions of the anterior pituitary
  25. 25. Hypothalamic Control of Posterior Pituitary• Hypothalamus neuron cell bodies produce: – ADH: supraoptic nuclei. – Oxytocin: paraventricular nuclei.• Transported along the hypothalamo- hypophyseal tract.• Stored in posterior pituitary.
  26. 26. EMOTIONAL CONTROL• Stimulation in Lateral hypothalamus inc general activity, sometimes leading to overt rage & fighting• Stimulation in Ventromedial nucleus causes opposite effects-------Tranquility
  27. 27. REGULATION OF CIRCADIAN RHYTHMS• Supachiasmatic nucleus establishes patterns of awakening & sleep• Receives input from retina• Sends output to other hypothalmic nuclei, reticular formation & pineal gland
  28. 28. Circumventricular Organs• Parts of diencephalon, called CVO b/c they lie in walls of 3rd & 4th ventricals.• Component: Hpothalamus, pineal & pituitary gland.• Monitor chemical changes in blood b/c lack a blood brain barrier• Thought to be the site of entry of HIV into brain

×