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Hormonal Control of Behavior

Hormonal Control of Behavior. Lecture 22. Chemical Control of Brain. Point-to-point control closed-circuit synapse fast, short-lived, local Diffuse control widespread control slower, longer lasting Neuroendocrine system Diffuse modulatory system ~. Neurohormones.

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Hormonal Control of Behavior

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  1. Hormonal Control of Behavior Lecture 22

  2. Chemical Control of Brain • Point-to-point control • closed-circuit • synapse • fast, short-lived, local • Diffuse control • widespread control • slower, longer lasting • Neuroendocrine system • Diffuse modulatory system ~

  3. Neurohormones • Interact with nervous system • Chemical message • Neurotransmitters (NTs) • Hormones • Pheromones • What’s the difference? ~

  4. Neurohormones • Similarities • chemical messengers • act at receptors • influence behavior • Differences • medium • distance traveled • time course ~

  5. Function • Developmental • sex differentiation • testosterone, estradiol • Regulatory • Insulin, CCK, etc. • Vasopressin, Oxytocin ~

  6. Types of Neurohormones • Amino acid-derived hormones • e.g. epinephrine • released from adrenal medulla • Protein & Peptide Hormones • Bind to membrane receptors • Activate the 2nd messenger system ~

  7. Types of Neurohormones • Steroid Hormones • Derived from cholesterol • Soluble in lipids • Bind to cytoplasmic receptors • regulates gene expression • e.g. sex hormones ~

  8. Neuroendocrine System • Brain • Hypothalamus • Releasing Hormones • Pituitary gland • Anterior: tropic hormones • Posterior: neurohormones • Glands - Hormones ~

  9. Pituitary Gland • 2 parts • different developmental origins • Anterior pituitary (adenohypophysis) • no axons from hypothalamus • parvocellular neurosecretory cells • portal system • Posterior pituitary (neurohypophysis) • axons from hypothalamus • magnocellular secretory cells ~

  10. G Hypothalamus Pituitary Stalk Pituitary hypophysis Posterior Pituitary- Neurohypophysis Anterior Pituitary- Adenohypophysis

  11. Posterior Pituitary:SupraopticohypophysealTract

  12. Supraoptic nucleus PVN Posterior Pituitary

  13. Posterior Pituitary: Neurohormones • Magnocellular neurosecretory cells • Supraoptic & Paraventricular Nuclei • Neurons fire  Neurohormones released • Transported down axons • to posterior pituitary • Peptide Neurohormones • Oxytocin • Vasopressin ~

  14. Posterior Pituitary: Neurohormones • Oxytocin • Induces uterine contractions • Triggers lactation • Antidiuretic Hormone (ADH) • AKA: Vasopressin • Regulates blood pressure • Promotes water retention ~

  15. Anterior Hypothalamus:HypothalamopituitaryPortal System

  16. Anterior Hypothalamus • Primordial tissue from roof of mouth • No axons from hypothalamus • Parvocellular neurosecretory cells • Releasing hormones • triggers release of tropic hormones • Tropic hormones  various glands gonads adrenal • mammary thyroid ~

  17. Hypothalamopituitary Portal System • Portal Systems • Capillary beds • Connected by a vein • e.g. hepatic portal vein • Hypothalamus  Anterior Pituitary ~

  18. Capillary Beds Portal Vein G Neuron PVN

  19. Cortisol Regulation • Adrenal glands • medulla: NE & E • cortex: cortisol • Regulation of cortisol • steroid • fight/flight & immunosuppression • stress response • Receptors widely distributed ~

  20. Cortisol Regulation • Hypothalamus • Corticotropin-releasing hormone (CRH) • Anterior pituitary • Adrenocorticotropin (ACTH) • Adrenal cortex • Cortisol • Negative feedback to hypothalamus • cortisol inhibits own release ~

  21. Sex Hormones • Hypothalamus • Gonadotropin-releasing hormone - GRH • isolated from pig hypothalami • Anterior Pituitary - • Gonadotropins • Follicle stimulating hormone - FSH • Lutenizing hormone - LH ~

  22. Gonadotropins: Target Cells • Gonads • Testes - • Androgens -Testosterone • Ovaries - • Estrogens • Estradiol and Progesterone ~

  23. Gonadotropin Release Patterns • Sex differences • FSH & LH both sexes • Males  steady • Females • cyclical • Transplant male pituitary into female? ~

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