Neurohypophysial hormones

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Definition

noun

The hormones synthesized by the magnocellular secretory neurons of the hypothalamus, and released from the axon terminals that extend to the neurohypophysis


Supplement

The neurohypophysial hormones refer to the various hormones produced by the specialized neurons (particularly, the magnocellular secretory neurons) in the hypothalamus. The hypothalamus is the region of the brain made up of several small nuclei. It is located between the thalamus and the midbrain. Since it produces hormones, it is considered as a part of the endocrine system (apart from the nervous system). The hormones that the hypothalamus produces control metabolism by exerting an influence on the function of the pituitary gland.

The neurohypophysial hormones are hormones produced by specialized hypothalamic nuclei whose axons extend to the neurohypophysis (also called posterior pituitary). The neurohypophysial hormones are released from the posterior pituitary into the circulation to reach target cells. These hormones are opposed to the hypothalamic hormones (or releasing hormones) that are produced by specialized neurons that have axon terminals that extend and form the bulk of the median eminence.

The axon terminals serve as the site of temporary storage of these hormones. In the neurohypophysis, the axon terminals of the specialized hypothalamic nuclei contain Herring bodies that store neurohypophysial hormones. They are produced by the hypothalamus but they are released from the neurohypophysis (thus, the name).

Neurohypophysial hormones include the neurohormones: oxytocin and vasopressin. These hormones are involved in the regulation of blood pressure, uterine wall contraction, milk ejection, pair bonding, etc.


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