Flashcards in Histology of the Pituitary Gland Deck (69):
Where is the pituitary gland in the brain?
In the sella turcica of the sphenoid bone
What is the superior border of the pituitary gland?
Diaphragma sellae and hypothalamus
What is the inferior border of the pituitary gland?
What is the lateral border of the pituitary gland?
What is the anteroinferior border of the pituitary gland?
What is the anterosuperior border of the pituitary gland?
What arteries run laterally to the pituitary gland?
What is the large sinus situated inferiorly to the pituitary gland?
What is the clinical relevance of the proximity of the internal carotids to the pituitary gland?
Pituitary adenoma may impinge on internal carotids, causing neurological ssx
What is the CN that sits superiorly to the carotid artery at the level of the pituitary?
What is the CN that sits laterally to the carotid artery at the level of the pituitary?
What is the CN that sits inferior to the carotid artery at the level of the pituitary?
What arteries supply the anterior cortical border zone (anterolateral regions) of the brain?
ACA and MCA
What arteries supply the internal border zone (medial region) of the brain?
What arteries supply the posterior cortical border zone (posterolateral regions) of the brain?
MCA and PCA
How is access gained to the pituitary during surgery?
Go through the nostrils and break through the sphenoid sinus
What is primary empty sella syndrome? What is the usual presentation?
Arachnoid mater invades the sella turcica d/t defect in the sellar diaphragm, compressing the pituitary gland posteriorly, and widening the superior opening for the infundibulum
What is secondary empty sella syndrome?
Secondary ESS is the result of the pituitary gland regressing within the cavity after an injury, surgery, or radiation therapy. Individuals with secondary ESS due to destruction of the pituitary gland have symptoms that reflect the loss of pituitary functions, such as the ceasing of menstrual periods, infertility, fatigue, and intolerance to stress and infection.
What are the three portions of the anterior pituitary (in order, from superior to inferior)?
What are the two portions of the posterior pituitary?
What is the pars tuberalis?
The "collar" of the anterior pituitary that wraps around the infundibulum
What is the neurohypophysis?
What is the adenohypophysis?
From what layer of the developing fetus does the anterior pituitary gland form? Posterior?
Anterior = oral ectoderm
Posterior = Neuroectoderm
What is Rathke's pouch?
a depression in the roof of the developing mouth in front of the buccopharyngeal membrane. It gives rise to the anterior pituitary (adenohypophysis).
What part of the developing brain gives rise to the posterior pituitary?
What is the clinical significance of remnants of Rathke's pouch?
The development of a craniopharyngioma
What are the two signalling molecules for the development of Rathke's pouch?
Bone morphogenetic protein 4
Fibroblast growth factor 8
What is the cause of craniopharyngiomas in children? Adults?
Children = remnants from Rathke's pouch
Adults = Mature cells in the anterior hypophysis
What are the inferior hypophyseal arteries a branches of? What do these supply?
-Direct branches of the internal carotid
- Pars nervosa
What are the arteries that supply the infundibulum?
Superior hypophysial arteries
What is the connection between the superior and inferior hypophysial arteries?
What are the arteries that supply the primary capillary plexus of the pituitary, which is located in the infundibulum? What is the function of this plexus?
-Superior hypophysial arteries
-Collect hormones secreted from the hypothalamus
What are the veins that drain the primary capillary plexus to the secondary one, which is located in the anterior pituitary?
What is the capillary plexus found in the posterior pituitary supplied by?
Inferior hypophyseal arteries
What is the normal connective tissue in the pars distalis? What happens to this with the development of a pituitary adenoma?
Loss of this CT
What is the general layout of the histology of the pituitary gland?
Sinusoidal capillaries broken up by cords of epithelial cells
What are the three types of cords of epithelial tissue found in the pituitary?
What are the types of hormones that are released by basophils?
What are the types of hormones that are released by acidophils?
What are the types of hormones that are released by chromophobes?
none- cell that has discharged its contents
Acidophils or basophil: somatotropes? What do these cells secrete?
Acidophils or basophil: Mammotrophs (lactotrophs)? What do these cells secrete?
What is the chemical cascade that occurs with GnRH secretion from the hypothalamus?
GnRH stimulates somatotropes to release GH, which increases IGF-1 from the liver.
Acidophils or basophil: Corticotrophs? What do these cells secrete?
ACTH and Beta-lipotropic hormone
Acidophils or basophil: Gonadotropes? What do these cells secrete?
LH and FSH
Acidophils or basophil: Thyrotropes? What do these cells secrete?
What are the only two acidophils in the pars distalis?
Somatotropes and mammotrophs
What is the chemical cascade that occurs with TRH/PRH release from the hypothalamus?
PRH/TRH stimulates mammotrophs to secrete prolactin, which increases lactogenesis
What is the primary inhibitor of prolactin secretion?
What is the major stimulus for prolactin secretion?
True or false: there are acidophilic stem cells in the normal pituitary that secrete both GH and prolactin
True, but these are rare
True or false: either gonadotropes secrete FSH, or they secrete LH, never both
False, can be both or either/or
What are the cells that FSH acts on?
What are the cells that LH acts on?
What cells does ACTH stimulate?
Two inner regions of the adrenal glands (fasciculata and reticularis)
What is the mucoid wedge of the pituitary?
Anterior and medial part of the pituitary that contains ACTH secreting cells and thyrotropes
Where are the gonadotropes located in the pituitary?
Where are the mammotrophs located in the pituitary?
Posteriorly in the anterior pituitary
Where are the gonadotrophs located in the pituitary?
What is Crooke's hyaline change?
Glassy appearance of corticotrophs d/t excess glucocorticoid production
What corticotrophs are not susceptible to the Crooke's hyaline change?
Those that invade the posterior pituitary
What is the neurohypophysis? Where do the cell bodies whose axons project into this area reside?
Collection of axons whose cell bodies reside in the supraoptic and paraventricular nuclei of the hypothalamus
What are the supporting cells of the neurohypophysis?
What are the Herring bodies found in the neurohypophysis?
Dilated area along the axons from the PVN and SVN that release the ADH/oxytocin
What is the function of the Neurohypophysis?
Release of ADH and oxytocin
What cells are primarily responsible for the synthesis of oxytocin?
What cells are primarily responsible for the synthesis of ADH?