Question

The posterior pituitary is?

1) one of the most important endocrine organs.
2) an organ producing (not just secreting) neurohormones.
3) just a physical extension of the hypothalamus.
4) a very small thin sheet in adult mammals.

Answer 1

The posterior pituitary, part of the neurohypophysis, is an extension of the hypothalamus and stores and releases hormones produced by the hypothalamus, specifically ADH and oxytocin. It does not synthesize its own hormones. Option 3 is the correct answer.

Step-by-step explanation:

The posterior pituitary is an integral part of the endocrine system and varies significantly in structure from the anterior pituitary. Unlike the anterior pituitary, which produces its own hormones, the posterior pituitary serves as an extension of the hypothalamic neurons.

It consists of nerve fibers and neuroglial cells that support axons extending from the hypothalamus. Importantly, the posterior pituitary itself does not synthesize hormones; it stores and releases hormones produced by the hypothalamus, specifically the antidiuretic hormone (ADH) and oxytocin.

These hormones are conveyed down the axons within the infundibulum of the hypothalamic-hypophyseal tract and are eventually released into the bloodstream from the posterior pituitary. Therefore, identifying the correct option, given the student's selection, the posterior pituitary is principally 'just a physical extension of the hypothalamus'.