4 HP Axis pt 1 Flashcards
(57 cards)
what did aristotle say about the pituitary gland?
major connection through the 4 essential humours pass from the brain into the body
what did Rathke do about the pituitary gland?
distinguished 2 parts: anterior pituitary (adenohypophysis) and posterior pituitary (neurohypophysis)
what did Pierre Marie do?
associated pituitary tumors with acromegaly in 1886
what did Cushing do?
pioneered modern neurosurgical techniques
what functions were discovered to be controlled by the pituitary?
- growth (GH)
- lactation (PRL)
- action on thyroid (TSH)
- action on the adrenals (ACTH)
- action on the gonads (LH & FSH)
what is the pituitary gland controlled by?
the nervous system via the hypothalamus
what components make up the hypothalamo-hypophyseal tract?
- rathke’s pouch
- infundibulum
where does the infundibulum come from? where does it go?
it’s an outgrowth of the neuroectoderm from the floor of the third ventricle.
gives rise to pituitary stalk, median eminence, posterior pituitary
what is a nucleus in the context of the hypothalamic-pituitary axis?
group of similarly functioning neurons
how are the hypothalamus and pituitary glands connected?
- ant. pituitary’s got hella vessels that’s connected to the median eminence
the picture looks like a seahorse and like, where the head and neck meet, that’s where the median eminence starts. also on the head there’s secretory neurons that are the seahorse’s antlers
so releasing factors go from median eminence to the pituitary
there’s also some retrograde blood flow to enable negative feedback from pit to hypothalamus
what’s the adenohypophysis?
anterior pituitary gland (they both start with A)
what’s a plexus?
a highly vascularized area
hi ruru
:)
where do the nerve endings go in the anterior pit?
in the plexus regions. it’s where releasing hormones are released.
pituitary enter the bloodstream via _____ capillaries
venous
describe how the hypothalamus can control the pituitary gland
- seahorse: nerve endings in the median eminence release hormones here
- hormones are uptaken in capillaries
- take a hike to the anterior pituitary via portal vein
- trigger the anterior pituitary to release a second wave of hormones
- 2nd wave hormones enter bloodstream via venous capillaries
describe how nerves are situated in the posterior pituitary
posterior pituitary’s got the axons whose cell bodies are in the hypothalamus
what hormones are produced in the neuronal cell bodies of the hypothalamus?
oxytocin, vasopressin (ADH)
true or false: oxytocin and vasopressin are packaged stored in granules
true
what happens when neurons in the hypothalamus are stimulated?
triggered to release hormones from axon tips located in posterior pituitary; hormones get uptaken by capillaries there
why aren’t oxytocin and vasopressin considered neurotransmitters even though they originate from neurons?
they don’t travel to the next neuron; they get released into the bloodstream
how were the functions of the hypothalamic nuclei discovered?
selective destruction of areas
what kind of neurons are in the hypothalamus?
- magnicellular
- parvicellular hypophyseotropic neuron
- hypothalamic projection neuron
describe magnicellular neurons
start in hypothalamus, end in posterior pituitary; release hormones into capillaries there
