Anterior pituitary

A major organ of the endocrine system, the anterior pituitary (also called the adenohypophysis or pars anterior) is the glandular, anterior lobe that together with the posterior lobe (posterior pituitary, or the neurohypophysis) makes up the pituitary gland (hypophysis). The anterior pituitary regulates several physiological processes, including stress, growth, reproduction, and lactation. Proper functioning of the anterior pituitary and of the organs it regulates can often be ascertained via blood tests that measure hormone levels. The pituitary gland sits in a protective bony enclosure called the sella turcica (Turkish chair/saddle). It is composed of three lobes: the anterior, intermediate, and posterior lobes. In many animals, these lobes are distinct. However, in humans, the intermediate lobe is but a few cell layers thick and indistinct; as a result, it is often considered part of the anterior pituitary. In all animals, the fleshy, glandular anterior pituitary is distinct from the neural composition of the posterior pituitary. The anterior pituitary is composed of three regions: Pars distalis The pars distalis (distal part) comprises the majority of the anterior pituitary and is where the bulk of pituitary hormone production occurs. The pars distalis contains two types of cells, including chromophobe cells and chromophil cells. The chromophils can be further divided into acidophils (alpha cells) and basophils (beta cells). These cells all together produce hormones of the anterior pituitary and release them into the blood stream. Nota bene: The terms "basophil" and "acidophil" are used by some books, whereas others prefer not to use these terms. This is due to the possible confusion with white blood cells, where one may also find basophils and acidophils. File:Histology of pars distalis of the anterior pituitary with chromophobes, basophils, and acidophils, annotated.jpg|Microanatomy of the pars distalis showing chromophobes, basophils, and acidophils File:Histology of anterior pituitary eosinophilic follicles.