Exam 6: Neuroendocrine/pituitary Flashcards
What is the main sensory information that gets sent to the hypothalamus?
Blood pressure and temperature
What are the trhee parts of the anterior pituitary?
Pars tuberalis, pars distalis, pars intermedia
What are the two parts of the posterior pituitary?
infundibular stalk, posterior lobe
What do neurons of the posterior pituitary secrete?
vasopressin and oxytocin
What cells of the posterior pituitary make vasopressin and oxytocin? where are they located?
magnocellular neurons; supraoptic and paraventricular nuclei
where do magnocellular nuclei secrete their peptides (oxytocin and vasopressin)?
Directly into systemic circulation
What are the functions of vasopressin?
Increase water resorption in kidney, anti-diuretic, vasoconstriction. All raise blood pressure
What are the stimuli that increase the release of vasopressin?
increased blood osmolality, hypovolemia, hypotension
What are the functions of oxytocin?
smooth muscle contraction in breast to release milk, smooth muscle contraction in uterus to deliver baby
What are the stimuli that increase release of oxytocin?
suckling, uterine stimulation
What are the three families of hormones that the anterior pituitary secretes?
Somatomammotropins, glycoproteins, opiomelanocortin peptides
What are the hormones under “somatomammotropins” secreted by the anterior pituitary?
Growth hormone, prolactin
What are the hormones under “glycoproteins” secreted by the anterior pituitary?
Thyroid stimulating hormone, follicle stimulating hormone, luteinizing hormone
What are the stimuli and effects of growth hormone?
exercise, stress, sleep; tissue growth and increased cellular metabolism
What are the stimuli and effects of prolactin?
suckling, stress; development of mammary tissue, lactation
What are the stimuli and effects of TSH?
exposure to cold temps; increase thyroid hormone to increase cell metabolism which raises body temp
What are the effects of FSH?
men: increased spermatogenesis, women: increased development of ovarian follicles
What are the effects of LH?
Men: works w/ FSH to increase spermatogenesis, stimulates testosterone, women: initiates ovulation, stimulates progesterone
What are the hormones of opiomelanocortin peptides secreted by the anterior pituitary
adrenocorticotropic hormone, Beta-endorphine
What are the stimuli and effects of ACTH?
stress; secretion of cortisol from adrenaline
What are the stimuli and effects of Beta-endorphine?
stress; analgesia
What are the precursors of opiomelanocortin peptides (ACTH and Beta-endorphine
pro-opiomelanocortin (POMC)
Which is a shorter peptide: ACTH or Beta-endorphine?
ACTH
What test could be used clinically to assess anterior pituitary function?
Inducing stress by injecting a small amount of insulin to induce hypoglycemia, leads to increased ACTH, Cortisol, Beta-endorphine, growth hormone
What controls the release of anterior pituitary hormones?
Hypothalamic releasing hormones
Describe the release of hypothalamic releasing hormones
synthesized in parvocellular neurons, transported via axons to median eminence, released from nerve terminals into hypophyseal portal vein where it travels to the secondary capillary bed in ant. pit. lobe and stimulates specific cells for specific hormones
What are the excitatory hypothalamic releasing hormones and their targets?
thyrotrophin releasing hormone (TSH), gonadotropin-releasing hormone (FSH, LH), corticotropin-releasing hormone (ACTH, Beta endorphine), growth hormone-releasing hormone (Growth hormone)
What are the inhibitory hypothalamic releasing hormones and their targets?
somatostatin (GH), dopamine (Prolactin)
What hormonal changes occur after pituitary stalk section?
Increased prolactin, decrease of all other pituitary hormones
What is diabetes insipidus?
Increase in water excretion leading to electrolyte imbalances
What is the etiology of DI?
head trauma severing the stalk of the pituitary leading to decreased vasopressin, autoimmune destruction of magnocellular neurons, idiopathic
What are the symptoms of DI?
polyurea, polydipsia
What is the treatment of DI?
desamino-vasopressin, increased retention of H2O in the kidney
What is galactorrhea-amenorrhea?
inappropriate lactation; hyperprolactinemia with cessation of menstraution
What is the etiology of galactorrhea-amenorrhea?
microadenoma in pituitary that released prolactin, leading to decreased FSH and LH
what is the treatment of galactorrhea-amenorrhea?
surgery, drugs DA receptor agonists to block prolactin
