Pituitary gland histology

The pituitary gland, is a small gland with a diameter of approximately 1 cm.It sits within a saddle-shaped bony cavity called the sella turcica, at the base of the brain.The gland is divided into two main parts, the anterior pituitary or adenohypophysis; and the posterior pituitary or neurohypophysis.Each part originates from different embryological sources, which is reflected in their different structure and function.“Adeno” means “related to glands” and the adenohypophysis consists primarily of glandular epithelial tissue.In comparison, the neurohypophysis consists mainly of neural secretory tissue, since the neurohypophysis arises from a bud of nervous tissue that grows down from the hypothalamus.In this low power, para-sagittal section of the pituitary gland, the anterior and posterior parts of the pituitary can be identified pretty easily when stained with Masson’s trichrome.Generally, this stain will stain nuclei and basophilic structures blue, collagen will be blue or green, and non-basophilic cytoplasm and red blood cells will be red.The posterior pituitary is composed of mostly unmyelinated axons, which don’t have nuclei or a large amount of collagen.So as a result, the posterior pituitary doesn’t stain well and will look significantly lighter when compared to the anterior pituitary.Whether it’s stained with Masson’s trichrome or Hematoxylin and eosin.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 Rathke’s pouch, which is the embryological structure that eventually develops into the anterior pituitary.Zooming in closer to the pars intermedia, the colloid-filled cysts can be seen more clearly, along with irregular clusters of basophilic cells, that often invade the neighboring neurohypophysis as well.Looking even closer, we can see a portion of the pars intermedia that has an area of lymphocyte infiltration.It’s also easier to see that the adenohypophysis has a much richer blood supply compared to the neurohypophysis, with many small blood vessels present throughout the adenohypophysis, including the pars intermedia.Alright, let’s move anteriorly and take a closer look at the adenohypophysis.Besides the bright red erythrocytes, there are two main groups of cells that are named based on how well they stain.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.The chromophils can then be divided into acidophils that stain dark red, and basophils that stain purplish-blue due to their affinity for acidic or basic dyes respectively.Acidophils consist of somatotrophs and lactotrophs, therefore they’re responsible for secreting growth hormone or somatotropin, and prolactin.The basophilic cells consist of corticotrophs, gonadotrophs, and thyrotrophs.So they secrete the remaining hormones associated with the anterior pituitary, including: Melanocyte-stimulating hormone or MSH, Adrenocorticotrophic hormone ACTH, Luteinising hormone or LH, Follicle-stimulating hormone or FSH, and Thyroid-stimulating hormone or TSH.Let’s move onto the posterior pituitary, which consists mostly of unmyelinated axons with neurosecretory activity.These axons can be seen throughout this image as the lightly stained portions of the tissue.The axons carry oxytocin and anti-diuretic hormone or ADH, from the hypothalamus down to their dilated nerve terminals called herring bodies, which are neurosecretory bodies.The herring bodies release either oxytocin or ADH, which is carried away by nearby capillaries.Also seen more clearly in this image are the highly branched pituicytes, which are the supporting glial cells.##SummaryAlright, as a quick recap.

The pituitary gland has two main parts, the anterior adenohypophysis and the posterior neurohypophysis.The anterior pituitary is made primarily of glandular tissue that is broadly split into chromophils and chromophobes.The chromophils are then further divided into basophils that stain purplish-blue and acidophils that stain dark red.The posterior pituitary is primarily neural tissue.Under high magnification, the distended nerve terminals called herring bodies can be seen, which release either oxytocin or ADH to be carried away by nearby capillaries.

of the tissue Jackson scary oxytocin and antidiuretic hormone or ADH from the hypothalamus down to their dilated nerve terminals called Herring bodies, which are neurosecretory bodies bodies released, either oxytocin or ADH.

What is carried away by nearby? Capillaries also seen more clearly in this image of the highly branched pituicytes, which are the supporting glial cells.

All right, as a quick recap, the pituitary gland has two main parts, the interior a dental hypothesis and the posterior neurohypophysis.

The anterior pituitary is made primarily of glandular tissue. That's probably split into chroma fails and chromophobes there, fellows are then further divided into basophils that sting purplish blue and a sitar.

Feels that same dark red. The posterior pituitary is primarily neural tissue under high.

Magnification. The distended nerve terminals called Herring bodies can be seen, which released either oxytocin or ADHD be carried away by nearby capillaries.