Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Hypothalamic Hormones Hypothalamic Hormones
Document related concepts
no text concepts found
Transcript
Objectives of Studies Individual Hormone Hypothalamic Hypothalamic Hormones Hormones รศ.พญ. สุพรพิมพ เจียสกุล ภาควิชาสรีรวิทยา คณะแพทยศาสตรศริ ริ าชพยาบาล 1. Source and nature of hormone 2. Synthesis, secretion 3. Controlling of hormone secretion 4. Actions / mechanism of actions 5. Abnormal hormone secretions Hypothalamus-Anterior Pituitary Relationship Hypothalamic Hormones 1. 1. Releasing Releasing and and inhibiting inhibiting hormones hormones Î Î Regulate Regulate anterior anterior pituitary pituitary hormones hormones 2. 2. Posterior Posterior pituitary pituitary hormones hormones Î Î Vasopressin Vasopressin // Antidiuretic Antidiuretic Hormone Hormone Î Î Oxytocin Oxytocin Hypothalamus-Posterior Pituitary Relationship PVN Î Oxytocin SON Î Vasopressin Vasopressin or Antidiuretic Hormone (ADH) Neuroendocrine Reflex V1 receptors (IP3,Ca2+) (ADH) ¾ Oxytocin ¾ Vasopressin (ADH) Peptides 9 amino acids MW ~1000 5 รศ.พญ. สุพรพิมพ์ เจียสกุล ภาควิชาสรีรวิทยา คณะแพทยศาสตร์ศิริราชพยาบาล V2 receptors (cAMP) Mechanism of ADH Action Î Mechanism of ADH Action Î Activates water channels (Aquaporins) Increase Na+ & urea transport into renal medulla Passive water reabsorption between cells fallows electrochemical gradient Control of ADH Secretion Effects of Vasopressin or ADH Physiological dose Î Increases water reabsorption • Alcohol • Atropine Urine flow (Antidiuresis) Urine osmolality High dose • Nicotine • Morphine Plasma ADH (pg/ml) % Blood Volume Depletion More sensitive less response Plasma ADH (pg/ml) Plasma ADH (pg/ml) Î Vasopressive effect Arterial Blood pressure Large Volume Depletion Osmoreceptors Vagus N firing Plasma osmolality~2% Blood volume ~ 10% Decreased plasma solute concentration ADH Dilution of plasma Atrial volume receptors Blood volume ADH Water retained Kidney Abnormal ADH Secretion Small Volume Depletion ADH Deficit Euvolemia Water Diuresis Diabetes Insipidus (DI) ( Neurogenic or Nephrogenic types) Plasma Osmolality (mOsm/kg) Urine volume Blood volume Plasma Osmolality (mOsm/kg) + CNS stimulation - ANP + Angiotensin II + SON Hypothalamic + ADH Plasma osmolality More response less sensitive stress: pain,trauma,anxiety urine osmolality & sp.gr Plasma osmolality Reset osmolality threshold for ADH Thirst / low blood volume & blood pressure 6 รศ.พญ. สุพรพิมพ์ เจียสกุล ภาควิชาสรีรวิทยา คณะแพทยศาสตร์ศิริราชพยาบาล Syndrome of Inappropriate ADH (SIADH) Oxytocin Î Action Action ( Ca2+ mediated) ADH excess Stimulate Stimulate Milk Milk Ejection Ejection (( Milk Milk Let-down Let-down )) Water Retention Urine volume Contraction of myoepithelial cells surrounding mammary alveoli Urine osmolality & sp.gr Plasma osmolality (1) Plasma Na+ Control of Oxytocin Secretion Oxytocin Î Action Suckling reflex (2) Cervical stretch Stimulate Stimulate Myometrial Myometrial Contraction Contraction Touch receptors at nipple Milk ejection Oxytocin release ¾ Increased oxytocin sensitivity of uterus and breast during pregnancy (Estrogen increases oxytocin receptors) Uterine contraction Contraction of myoepithelial cells of mammary gland ¾ Facilitate parturition at birth (slow delivery in the absence of H) Oxytocin release Child birth ¾ Stop postpartum bleeding HT-AP- Endocrine Gland Relationship Abnormal Hormone Secretion Synthesis, Storage, No Known Disease Release from Anterior of Pituitary Oxytocin Excess Hormones or Deficiency Parvicellular neurosecretory cells synthesize releasing and inhibiting hormones Transported to axon endings of median eminence Released into HT-PT portal system Regulate secretions of anterior pituitary hormones PRL,TSH,ACTH,GH,LH, FSH 7 รศ.พญ. สุพรพิมพ์ เจียสกุล ภาควิชาสรีรวิทยา คณะแพทยศาสตร์ศิริราชพยาบาล Hypothalamic Releasing and Inhibiting Hormones Hypothalamic Releasing and Inhibiting Hormones ¾ Minute amount-rapid and high potency ¾ No species specific Anterior Pituitary Hormones ¾ React with membrane receptors (Ca2+,PI products, cAMP) Trophic effect ¾ Intrinsic neural oscillator control + ¾ Adequate pulsatility required for optimal Stimulates hormone secretion effects 8 รศ.พญ. สุพรพิมพ์ เจียสกุล ภาควิชาสรีรวิทยา คณะแพทยศาสตร์ศิริราชพยาบาล
