key concept 40.2 The Endocrine System and Nervous System Work Together

The nervous system and the endocrine system control and regulate virtually all physiological and behavioral mechanisms that contribute to homeostasis, survival, and reproductive success. Challenges to an organism usually trigger both physiological and behavioral responses, as we saw with respect to thermoregulation in Chapter 39 and also with the fight-or-flight reactions shown in Figure 40.3. Therefore the endocrine and nervous systems must work together in an integrated fashion, and indeed they do. The nervous system receives an enormous amount of information from the body and from the environment. That information is critical for maintenance of homeostasis, survival, and reproductive success. The nervous system controls many tissue and organ functions as well as behavior. It is therefore not surprising that the nervous system regulates many endocrine functions. Conversely, hormones circulate to the nervous system, providing feedback information used in regulation. Hormones reaching the brain also stimulate behaviors that contribute to the health and well being of an organism.

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  • Oxytocin and vasopressin are produced in the hypothalamus and secreted from nerve terminals in the posterior pituitary.

  • The anterior pituitary produces four tropic hormones plus growth hormone, prolactin, and melanocyte stimulating hormone.

  • The release of hormones from the anterior pituitary is controlled by hypothalamic hormones transported to the pituitary in portal vessels.

  • Regulation involves short-loop and long-loop negative feedback.