L9 Flashcards
(48 cards)
Some hypothalamic hormones are
transported to capillaries in the _________ and released into capillaries there for transport to distant tissues
posterior pituitary
Some hypothalamic hormones
(releasing factors) enter capillaries
that merge into portal veins which
branch into more capillaries in the
_________ to govern the release of trophic hormones there
anterior pituitary
hormones released by the anterior pituitary (6)
ACTH, TSH, LH, FSH, Prolactin, GH
true or false: the anterior pituitary has neurons/synapses
false — no neurons, only cells producing hormones
the anterior pituitary is also known as _______
the adenohypophysis
what is the Rathke pouch?
a structure of ectodermal origin that folds superiorly from the pharynx
during the fourth week of gestation
In the sella, Rathke pouch gives rise to the adenohypophysis anteriorly and intermediate lobe of the pituitary
gland posteriorly. In the suprasellar cistern, Rathke pouch gives rise to the pars tuberalis.
what is a Rathke cleft cyst and how does it form?
Failure of embryonic regression results in a persistent remnant of the embryologic Rathke cleft, which, over time, fills with fluid, resulting in the
formation of a Rathke cleft cyst.
typically intrasellar, intrasellar and suprasellar, or suprasellar, depending on location
Mutations in _________ have been identified in mice and in patients with hypopituitarism.
pituitary-specific transcription
factors
describe sequential appearance of pituitary cell types
sequential appearance of the
terminally differentiated cell types:
gonadotrophs, thyrotrophs, somatotrophs, lactotrophs, and corticotrophs located ventrally to dorsally, respectively
where are the target cells of ADH?
kidney tubules
where are the target cells of oxytocin (two answers)?
smooth muscle in uterus and mammary glands
where are the target cells of ACTH?
adrenal cortex
where are the target cells of prolactin?
mammary glands
where are the target cells of growth hormone (2 answers)?
bones, tissue
where are the target cells of gonadotropic hormones (2 answers)?
ovaries, testes
negative inhibitor of prolactin released by hypothalamus
dopamine
negative inhibitor of GHRH
somatostatin
Five cell types in the adenohypophysis by immunostaining
1- LACTOTROPHS (Mammotrophs): Prolactin (Prl) - acidophils.
2- SOMATOTROPHS: growth hormone (GH) - acidophils.
3- CORTICOTROPHS: proopiomelanocortin (POMC) precursor for ACTH, melanocyte stimulating hormone
(MSH), beta-endorphin, and beta-lipotropin - basophils.
4- THYROTROPHS: thyroid stimulating hormone (TSH) - basophils.
5.GONADOTROPHS: FSH/LH - basophils.
most common cause of excess/inappropriate production of anterior pituitary hormones
an adenoma of the anterior lobe
Adenomas may be nonfunctional
and cause _______ by compressing adjacent normal parenchyma
hypopituitarism
Most pituitary adenomas are ______ in origin
monoclonal
what is a pituitary adenoma?
a non-cancerous (benign) tumor that grows in the pituitary gland, located at the base of the brain
most are small and asymptomatic. larger ones can press on surrounding tissues and lead to headaches and vision loss
non-functioning pituitary tumor vs pituitary adenoma
a non-functioning pituitary tumor is a type of pituitary adenoma that does not produce excess hormones, meaning it doesn’t cause hormonal imbalances in the bod
why do non-functioning pituitary tumors cause symptoms and what are those symptoms?
they cause symptoms due to space occupation
- headache
- visual field defects
- nerve palsies
- interfere with rest of pituitary function - deficiency of hormones
