Tuesday 3 - engeland - hypothalmus Flashcards
what does the fornix lead to
mammilary bodies to hypothalmus via mammilothalamic tract
Role of posterior pituitary with regards to hormones
secretion of Vasopressin or Oxytocin (a single neuron cannot release both) into systemic circulation
Where are the hormones secreted by the posterior pituitary made?
Where are they secreted from?
magnocellular neurons (HUGE neurons) in the supraoptic (SON) and paraventricular nuclei (PVN)
secreted from the axons of these nuclei that travel allll the way down into the posterior pituitary and are stored in vesicles until released by neural activity
What nuclei in the brain supply neurons that go towards the paraventricular nucleus and the supraoptic nucleus, making them release (or hold onto) their neurotransmitters?
limbic area of the brain (motivation, emotion)
solitary tract (nucleus is in the medulla)
vasopressin
3 big stimuli for its release and what does it do to resolve these stimuli
another name for it?
increase blood solutes -> increase in water resorption by kidney
hypovolemia -> increase in water resorption by kidney
hypotension -> vasoconstriction to increase BP
anti-diuretic hormone (ADH)
oxytocin
2 big stimuli for its release and what does it do to resolve these stimuli
use as a drug?
suckling -> milk ejection reflex causes smooth muscle contraction to eject milk
uterine stimulation -> uterine contraction leading to delivery
used in helping couples bond by shoving it up their noses…
two somatomammotropins
growth hormone
prolactin
Stimuli and effects of growth hormone
stimuli: exercise, stress, sleep (80 % of effect is during slow wave sleep)
effect is growth ya dingus
also metabolism
stimuli and effects of prolactin
stimuli: suckling and stress
effects: development of mammary tissue and production of milk
Stimuli and effects of thyroid stimulating hormone
stim: exposure to cold temp
effects: increase in secretion of thyroid hormone; increase in cell metabolism; increase in heat production
stim and effects of follicle-stimulating hormone (FSH)
(gonadotropic hormone)
regulated by hypothalamic peptide
effects: men: spermatogenesis
women: development of ovarian follicle
stim and effects of luteinizing hormone (LH)
(gonadotropic hormone)
regulated by hypothalamic peptide
effects: men: required for spermatogenesis, stimulates testosterone
Women: initiates ovulation and stimulates progesterone
opiomalanocortin peptides stim and effects
general things about it too
melano- meaning plays a role in stimulating the melanocytes
-cortin meaning involved in adrenal cortex
when cleaved, it makes multiple biologically active fragments!!!!!:
adrenocorticotropic hormone (ACTH) - stress stimulates release, causes secretion of cortisone from the adrenal cortex
beta-endorphin - stress stimulates release, effects are opiate like, causing analgesia.
what test could be used clinically to assess anterior pituitary function?
what does it release
give insulin to induce hypoglycemia, causes activation of things from anterior pituitary like cortisol via ACTH, beta endorphin, prolactin, growth hormone
pathway of the stimulation and release of the anterior pituitary hormones
(no direct arterial supply to anterior pituitary cells)
hypothalmus releases hormones secreted into primary plexus
carried to pituitary cells via hypophyseal portal vein
goes to the secondary capilary body
causes release of hormone systemically
only pituitary hormone controlled by an excitatory and inhibitory pathway?
what does the excitation and inhibitions?
growth hormone:
inhibited by somatostatin.
promoted by growth-hormone-releasing-hormone.
What pituitary hormone does dopamine inhibit?
prolactin
What hormonal changes would result from pituitary stalk section?
increase in prolactin, because it is the only one that is under net inhibition by the pituitary
all other hormones going to decrease
diabetes insipidus
cause
Sx
Tx
loss of vasopressin secretion
caused by:
head trauma, severing pituitary stalk
autoimmune destruction of magnocellular neurons
idiopathic
Sx: frequent urination (polyuria) excessive drinking (polydipsia)
Tx: vasopressin that acts selectively on the kidney. (Desaminovasopressin), doesn’t increase BP.
galactorrhea-amenorrhea
cause
Sx
Tx
usually microadenoma causes:
release of prolactin
inappropriate lactation and cessation of menstration
build up of prolactin thought to cause decrease in FSH, LH, which causes the cessation of menstration, can’t get pregnant
surgical Tx: removal of microadenoma,
pharmacological Tx: inhibit prolactin with dopamine receptor agonist
