hypothalamus and pituitary Flashcards
what is the pituitary gland is composed of?
anterior pituitary and posterior pituitary
where is vasopressin/ADH produced?
supraoptic nuclei of the hypothalamus
where is oxytocin produced?
magnocellular neurones of the PVN in the hypothalamus
what do the parvocellular neurones of PVN produce?
many releasing hormones such as gonadotropin releasing hormone (GnRH), growth hormone releasing hormone (GHRH), corticotropin releasing hormone (CRH), thyroid releasing hormone (TRH), dopamine and somatostatin
what do herring bodies do?
store vasopressin and oxytocin in posterior pituitary
what does the hypothalamic- hypophyseal portal system ensure?
that hypothalamic hormones reach endocrine cells of anterior pituitary with very little delay
what does the small blood flow in portal veins allow?
very small amounts of hypothalamic hormones from relatively few hypothalamic neurones to control secretion of anterior pituitary hormones without causing dilution in general circulation
what hormone does dopamine inhibit?
prolactin
what is the target organ of adrenocorticotropic hormone (ACTH)?
adrenal cortex
what hormone do somatotrophs produce?
growth hormone
what hormone inhibits growth hormone?
somatostatin
which is the most abundant anterior pituitary hormone?
growth hormone
what is the relationship between growth hormone levels and blood glucose levels?
increased blood glucose, decreased GH levels
what is involved in negative feedback of GH?
IGF-1 produced by liver in response to GH feedbacks to hypothalamus and anterior pituitary to shut off stimulus
what enhances growth hormone secretion?
- sleep
- exercise
- fasting (postprandial hypoglycaemia)
- increase in amino acids
- stress
what pathways do growth hormone receptor binding activate?
JAK2 and Src pathways
what kind of tissue is the anterior pituitary composed of?
glandular tissue
what kind of tissue is the posterior pituitary composed of?
neural tissue
where is the pituitary gland located?
- base of hypothalamus, sitting in sella turcica of sphenoid bone
- between cavernous sinuses
what are the 3 main cell types of the anterior pituitary?
- chromophobes (clear)
- chromophils (50%)
- acidophils (lightly stained) - 40%
- basophils (darkly stained) - 10%
what is the embryological origin of anterior pituitary?
oral ectoderm
what is the embryological origin of posterior pituitary?
nervous tissue from diencephalon from developing CNS
what are the other names for anterior pituitary?
pars distalis, adenohypophysis
what are the other names for posterior pituitary?
pars nervosa, neurohypophysis
which pituitary hormones share a common alpha-subunit?
FSH, LH, TSH
