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As more became known about neurosecretory cells, the difference between the actions of nerve communication and endocrine hormone release become less clear. Like the average neuron, these cells conduct electrical impulses along the axon but unlike these neurons, neurosecretion produces neurohormones that are released into the body’s circulation.
Magnocellular neurosecretory cells in rats (where these neurons have been most extensively studied) in general have a single long varicose axon, which projects to the posterior pituitary. Each axon gives rise to about 10,000 neurosecretory terminals and many axon swellings that store very large numbers of hormone-containing vesicles. [3]
Parvocellular neurosecretory cells are small neurons that produce hypothalamic releasing and inhibiting hormones. The cell bodies of these neurons are located in various nuclei of the hypothalamus or in closely related areas of the basal brain, mainly in the medial zone of the hypothalamus.
Herring bodies or neurosecretory bodies are structures found in the posterior pituitary. They represent the terminal end of the axons from the hypothalamus , and hormones are temporarily stored in these locations.
Each neuron in the nucleus has one long axon that projects to the posterior pituitary gland, where it gives rise to about 10,000 neurosecretory nerve terminals. The magnocellular neurons are electrically excitable: In response to afferent stimuli from other neurons, they generate action potentials, which propagate down the axons. When an action ...
The axons of the parvocellular neurosecretory neurons of the PVN project to the median eminence, a neurohemal organ at the base of the brain, where their neurosecretory nerve terminals release their hormones at the primary capillary plexus of the hypophyseal portal system. The median eminence contains fiber terminals from many hypothalamic ...
Most of the circulating oxytocin and vasopressin hormones are synthesized in magnocellular neurosecretory cells of the supraoptic nucleus and paraventricular nucleus of the hypothalamus. They are then transported in neurosecretory granules along axons within the hypothalamo-neurohypophysial tract by axoplasmic flow to axon terminals forming the ...
The posterior pituitary consists mainly of neuronal projections of magnocellular neurosecretory cells extending from the supraoptic and paraventricular nuclei of the hypothalamus. These axons store and release neurohypophysial hormones oxytocin and vasopressin into the neurohypophyseal capillaries, from there they get into the systemic ...