According to the wikipedia page on the diencephalon, the posterior pituitary gland is considered part of the diencephalon, but the anterior is not. Is there a reason that these two lobes of the same gland are considered different enough not to be part of the same brain region?


1 Answer 1


Worth going to the wikipedia page on the pituitary:

In all animals, the fleshy, glandular anterior pituitary is distinct from the neural composition of the posterior pituitary, which is an extension of the hypothalamus.

The anterior pituitary arises from an invagination of the oral ectoderm (Rathke's pouch). This contrasts with the posterior pituitary, which originates from neuroectoderm.

The posterior lobe develops as an extension of the hypothalamus, from the floor of the third ventricle.

In other words, the different parts of the pituitary are, developmentally, entirely separate. The posterior lobe is actually part of the hypothalamus. The anterior lobe is not even part of the brain.

Lumping them together with one label happened because the anatomists who originally named the thing didn't know much about it, which is not surprising because anatomical names are quite old and understanding of the functions of any parts of the brain is quite new. Old names stick.


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