Pituitary gland Flashcards
(44 cards)
What is a hormone?
A messenger carried from organ from where it is produced to the affected organ through the bloodstream
What are the two types of hormones?
Steroid and peptide
How are peptides synthesised as first
prohormones (long polypeptide chain) then cleaved by regulatory enzymes
how are peptide hormones stored and released?
stored in vesicles and released by regulatory (stimulatory secretion)
describe the receptors that peptide hormones bind to and how signal reach target?
Bind to receptors on cell membrane and transduce signal using 2nd messenger model
how are STEROID hormones synthesised to at first? I.e precursor to all steroid hormones
synthesised from CHOLESTEROL in a series of reaction
how are steroid hormones secreted?
Constitutive secretion
what type of receptor does steroid hormone bind to?
intracellular receptors- transcription factors
what is the pituitary stalk called?
infundibulum
what are the 2 parts of the pituitary gland?
anterior (adrenohypohysis) and posterior(neurohypophysis)
what are the 3 sections of the anterior pituitary gland
pars tuberalis
pars intermedia
pars distalis
where does the pituitary gland sit
sella turcica of the sphenoid bone
what part of the brain is located anterio- superior to the pituitary gland
optic chiasm
what neurons regulate the anterior pituitary function?
Hypothalamic parvocellular neurons
where does the parvocellular neurons terminate
median eminence
How does signals from parvocellular neurons reach anterior pituitary gland?
VIA hypothalamo-pituitary portal circulatory system
how is the anterior pituitary anatomically distinct from the hypothalamus?
DOES NOT contain neural tissue but contains glandular tissue, that’s why parvocellular neurons terminate in median eminence
what type of endocrine cells make up the anterior pituitary gland?
Somatotrophs Lactotrophs Gonadotrophs Corticotrophs Thyrotrophs
Describe in detail how the hypothalamus causes thyrotrophs to release THYROTROPHIN
hypothalamus parvocellular cells terminate in median eminece
secrete Thyrotrophin releasing hormone into portal system
goes to anterior pituitary (thyrotrophs) and causes thyotrophin to be released.
thyrotrophin released into the blood to thyroid gland
thyroid gland release thyroxin
list the endocrine cells of anterior pituitary and their respective hormones they produced
somatotrophs- Growth hormone Lactotrophs- Prolactin Gonadotrophs- FSH and LH Thyrotrophs- thyrotrophin corticotrophs- Adenocorticotrophic hormone(ACTH)
Which hormone produced by the parvocellular cells stimulate or Inhibit production of growth hormone
Stimulate- Growth hormone releasing hormone.
Inhibit- Somatostatin
What hormone controls release of prolactin from lactotrophs?
Dopamine- IT INHIBITS ONLY
What hormone controls release of TSH (Thyrotrophin)
THYROTROPHIN releasing HORMONE. IT STIMULATES only.
What hormone controls release of the following? LH/FSH and corticotrophin(ACTH)?
LH/FSH- gonadotropin elapsing hormone
ACTH- corticotrophin releasing hormones