Hypothalamus
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The hypothalamus contains several nuclear groups that regulate important physiological functions. The anterior group regulates hormone secretion and thermal regulation. The tuberal group contains nuclei that influence feeding behavior and metabolism. This includes the ventromedial nucleus which acts as a satiety center. The posterior group is involved in temperature regulation and the mamillary body processes inputs related to memory. Damage to different hypothalamic nuclei can disrupt these functions and lead to conditions like obesity, anorexia, or memory impairment.
Hypothalamus
- 1. and its functions Dr Priyanka, SMCH.
- 3. Nuclear groups: ANTERIOR / PREOPTIC GROUP PREOPTIC n PARAVENTRICULAR n ANTERIOR n SUPRAOPTIC n SUPRACHIASMATIC n MIDDLE / TUBERAL GROUP DORSOMEDIAL n VETROMEDIAL n LATERAL n ARCUATE/ TUBERAL n POSTERIOR / MAMILLARY GROUP POSTERIOR hypothalamic nuclei MAMILLARY, SUPRAMAMILLARY BODY
- 4. Regulates ant. pit. hrs (discrete area) Secretion of Post. Pit. hrs (SON, PVN) Controls adrenal cortex CRH PVN Controls ad. Medulla catecholamine (emotions) P, L, A nucleus
- 5. Regulation of food intake VMN (Satiety centre) Lateral Nucleus (Feeding Centre)
- 6. Temperature regulation PON (Heat loss) Post Hypothalamus (Heat gain)
- 7. Thirst centre OVLT, SFO Regulation of water intake SOP & PVN
- 8. Role in sleep & wakefulness Post Hypothalamus Circadian rhythm - SCN
- 9. Influences memory, emotion motivation behaviours VMN & Lateral nucleus stronger stimuli on Lateral nucleus activates Punishment centre Reward centre Medial Forebrain Bundle, (especially) Ventromedial hypothalamus & Lateral (weaker +)
- 10. Anterior group PARA- VENTRICULAR nucleus (PVN) Regulates water balance Synthesis & release of ADH - Vasopressin & Oxytocin CRH ,TRH , Somatostatin release SIADH, Central Diabetes Insipidus, Hypertension SUPRAOPTIC nucleus (SON) Regulates Water Balance Synthesis & Release of ADH - Vasopressin & Oxytocin SIADH, Central Diabetes Insipidus, Hypertension, addictions SUPRACHIASM ATIC nucleus (SCN) Biological clock Circadian rhythm = 24h lightdark cycle receives visual input from retina--optic tract Abolishes circadian rhythm, insomnia, narcolepsy PREOPTIC nucleus (PON) Regulates release of GnRH --- Ant Pit---- Androgens & Oestrogens Regulates Sexual behaviour (medial PON in females) thermoregulation Before puberty : arrest of sexual development After Puberty : amenorrhea, impotence, infertility ANTERIOR nucleus (AN) THERMAL REGULATION - Senses increase in Body temp. Response : heat dissipation. Stimulates : PNS Destruction leads to HYPETYHERMIA
- 11. MIDDLE or TUBERAL GROUP NUCLEI FUNCTION LESION EFFECTS DORSOMEDIAL nucleus Stimulation results in obesity and savage behaviour Destruction results in starvation FATAL ANOREXIA NERVOSA VETROMEDIAL nucleus Satiety Centre - cessation of eating destruction leads to HYPERPHAGIA - obesity & savage behaviour HYPOTHALAMIC OBESITY LATERAL hypothalamic area Feeding centre General sympathetic activation piloerction, rise in BP, sweating, pupillary dilation, Destruction results in starvation FATAL ANOREXIA NERVOSA ARCUATE/ TUBERAL nucleus produces hypothalamic releasing hormones Contains DOPA-ergic neurons that inhibit prolactin release
- 12. Posterior or Mammillary group POSTERIOR nucleus Thermal regulation (conservation of heat) Stimulates SNS Inability to thermo regulate MAMILLARY BODY / nuclei Receives input form limbic system & hippocampus Mammothalamic tract from thalamus Memory Wernickes encephalopathy Korsakoff psychosis (COAT n RACK)
- 13. Thank u