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The paraventricular nucleus in the hypothalamus is a microcosm of neuroendocrine, autonomic, and sensory-motor integration. The three structuralfunctional divisions of the paraventricular nucleus are shown. The magnocellular neuroendocrine division comprises two distinct although partly
interdigitated pools of neurons. These neurons normally synthesize vasopressin (VAS) and oxytocin (OXY) and release them from axons that course
through the internal zone of the median eminence and terminate in the posterior pituitary. Another population of magnocellular neuroendocrine neurons
lies in the supraoptic nucleus along the base of the brain.
The parvicellular
neuroendocrine
division
threethe
major,
separate (although
interdigitated)
poolsEditon
of neurons. Somatostatin (SS) neurons are
Source:
The Autonomic
Motorincludes
System and
Hypothalamus,
Principlespartly
of Neural
Science, Fifth
concentrated along the wall of the third ventricle; thyrotropin-releasing hormone (TRH) neurons are concentrated a bit more laterally; and corticotropinCitation: Kandel ER, Schwartz JH, Jessell TM, Siegelbaum SA, Hudspeth AJ, Mack S. Principles of Neural Science, Fifth Editon; 2012 Available
releasing hormone (CRH) neurons are concentrated even more laterally. Their axons end in the external zone of the median eminence, where they
at: http://mhmedical.com/ Accessed: April 30, 2017
release their peptide neurotransmitters into the hypophysial portal veins to control anterior pituitary hormone secretion.
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The descending division has three parts (dorsal, lateral, and ventral) with topographically organized projections to the brain stem and spinal cord. Axons