MCQ MAHE 2000 Anatomy Answer 3

The correct answer is A

The posterior lobe of the pituitary gland is smaller than the anterior lobe and embryologically derives from the neural primordia as an outpouching from the floor of the third ventricle.

Upwardly growing pituitary tumors, which reach appropriate sizes, impinge on the anterior notch of the chiasm at its lowest lying aspect. This produces the bitemporal hemianopsia with increased density superiorly. Since tumor growth is usually asymmetrical, the field loss between two eyes is also typically asymmetrical.

The anterior lobe contains three subdivisions including the pars distalis, pars intermedia and pars tuberalis. The pars distalis makes up the bulk of the anterior pituitary and is primarily responsible for the secretion of anterior pituitary hormones into the peripheral circulation. The pars intermedia lies between the pars distalis and the posterior pituitary and is vestigial in man, while the pars tuberalis is well defined in most mammalian species and surrounds the infundibular stem.

The hormones secreted by the posterior pituitary are actually produced in the Hypothalamus and carried to the pituitary gland through nerves.

Category: MAHE 2000 MCQs