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Pituitary Gland Histology

3 minutes 41 seconds

🇬🇧 English

S1

Speaker 1

00:04

The pituitary gland, or hypothesis, is a small gland which lies below the brain, in a small cavity on the sella

S2

Speaker 2

00:11

turcica. The pituitary actually consists of 2 glands, the posterior neurohypothesis and the anterior adenohypothesis, which are united anatomically. Adeno means related to glands, and the adenohypothesis consists primarily of glandular epithelial tissue. In comparison, the neurohypothesis consists mainly of neural secretory tissue, since the neurohypothesis arises from a bud of nervous tissue that grows down from the hypothalamus.

S2

Speaker 2

00:45

In between the anterior pituitary and posterior pituitary is a thin strip of cystic tissue called the pars intermedia, which is part of the anterior pituitary because the cysts are actually remnants of Rottke's pouch, which is the embryological structure that eventually develops into the anterior pituitary. Let's move anteriorly and take a closer look at the adeno hypothesis. There are 2 main groups of cells that are named based on how well they stain. They are chromophiles and chromophobes.

S2

Speaker 2

01:19

The chromophils have cytoplasm that stains strongly and as a result appears darker. And chromophobes have cytoplasm that stains weakly and appear lighter in the image. Chromophylls are secretory cells in which hormone is stored in cytoplasmic granules. They're also called basophylls and acetylphylls based on their affinities for basic and acidic dyes, respectively.

S2

Speaker 2

01:45

Acetylphylls stain orange to red with acidic dyes, and acidophils consist of somatotrophs and lactotrophs. Somatotrophs secrete somatotropin, or growth hormone. Thus, they are stimulated by growth hormone releasing hormone, and they're inhibited by somatostatin. Lactotrophs, the other variety of acetylfils, produce and release prolactin, which promotes mammary gland development during pregnancy, as well as lactation after birth.

S2

Speaker 2

02:16

The basophilic cells are the corticotrophs, gonadotrophs, and thyrotrophs. Basophils stain blue with basic dyes, and they secrete the remaining hormones associated with the anterior pituitary, including adrenocorticotrophic hormone, or ACH, luteinizing hormone, or LH, follicle stimulating hormone, or FSH, and thyroid stimulating hormone, or TSH. Let's move on to the posterior pituitary. The posterior pituitary contains non-myelinated axons, which are the neurosecretory cells.

S2

Speaker 2

02:57

The cell bodies of these cells are located in the hypothalamus. The secretory neurons have all the characteristics of typical neurons, including the ability to conduct an action potential, but have larger diameter axons and well-developed synthetic components related to the production of antidiuretic hormone, ADH, and oxytocin. Transported axonally, these hormones accumulate in axonal dilations called neurosecretory bodies or herring bodies. The herring bodies release either oxytocin or ADH which is carried away by nearby capillaries.