Pituitary and Hormones Flashcards
what 2 systems to the hypothalamus and pitutary gland link?
Nervous and Endocrine system
decribe the structure and location of the pitutary gland?
size of a pea and sits beaneath the hypothalamus in a socket of the bone at the base of the skull “sella turcica”
describe formation of each gland (embylogical origin)
-Anterior (adenohypophysis)
arises from oral ectoderm (Rathke’s Pouch), which is primitive gut tissue, it grows UP to meet the posterior pituatry gland.
-Posterior (Neaurphypohyis)
originated from the neuroactroderm. (primitive brain tissue)
which of the pituitary gland is not an actual gland? why?
Posterior (Neaurphypohyis) bc it doesn’t really make the hormones, it only STORES them
Describe the function of posterior and anterior pituitary glands and the routeof how their hormones r synthesized & released
Posterior Gland
Oxytocin & ADH r produced by neurosecretory cells in the
Supraoptic and paraventricular nuclei in hypothalamus, they r transported down the neurons into the posterior gland where they r STORED there.
Anterior gland
Hormones r made in hyothalamus
travel down axons & r stored in the Median eminence. (lower part of hypothalamus)
then theyre released into the Hypopheseal Portal system
these hormones then stimlaute the neurosecretory cells in the A. gland and these cells will talk to each other via paracrine or autocrine.
describe formation of each gland (embylogical origin)
-Anterior (adenohypophysis)
arises from oral ectoderm (Rathke’s Pouch), which is primitive gut tissue, it grows UP to meet the posterior pituatry gland.
-Posterior (Neaurphypohyis)
originated from the neuroactroderm. (primitive brain tissue)
where is ADH synthesized?
what is its function?
in neurosecretory cells in the hypothalamus (mostly supraoptic)
recepterd fro ADH r in the collecting duct of kidneys
what is a portal system?
linkage of 2 capillary beds
The hormones produced by nerve cells in the hypothalamus act via TWO distinct neurocrine pathways
describe them
Oxytocin & ADH released from hypothalamus> go to posterior> act on target tissues
Anterior shway 7osa….
Hormones secreted by the hypothalmu go down to the median eminence, then goes via the hypophyseal portal system then they STIMULATE the synthesis of the actual hormones in the Anterior lobe.
Hormones of the pOsterior and their function
Oxytocin> milk release & uterus contractions
ADH“vasopressin”> regulation of body water volume nad causes vasoconstriction too
REMInDER ALAA:
they r made in the supra and paracentricular nuclei of the hypothalamus, but stored in the Posterior gland.
ok?
what r tropic hormones?
Name the tropic hormones of the hypothalamus
Tropic hormones effect the release of other hormones in target tissue.
there r 7 in the hypothalmaus (which r stored in the median eminence) wich will effect the release of anterior pituatry hormones
TRH
PIH (dopamine)
PRH
CRH
GnRH
GHRH
GHIH (somatostatin)
these 7 hormones will leave the hyopothalamus and control the release of the 5 types of anterioir pituatry hormones
ALaa if u know ur anterior pitautry hormones, u know these!
what is another name for Dopamine?
PIH
which hormone is known as Somatostatin?
GHIH
what r the hormones of the Anterior pituatry glands?
what is the Pars intermedia
layer of cells located in btw the anterior and posterior lobe of the pitatury gland.
must know this alaa
ok
explain the Hypothalamic pitautry -adrenal axis with its feeback mechanisms! mention the triggers of release as well
ACTH can also inhibit hypothalamus too (short loop)
describe the terms
Hyperplasia
Atrophy
Hypertrophy
apoptosis
Hyperplasia> increase in cell #
Atrophy> decrese in cell size & #
Hypertrophy>increse in cell size
apoptosis> programmed cell death
is GH orally active? explain
No, because it is a protein and will be degraded.
Describe the role of GH in bone growth in kids and adults.
what is the epiphiseal plate?
epiphiseal plate: is a hyaline cartilage plate in the metaphysis at each end of a long bone. It is the part of a long bone where new bone growth takes place.
GH stimulates long bone growth
B4 epiphyseal closes= increases WIDTH & LENGTH of the bone
after epiphyseal closes= growth in WIDTH ONLY
what controls GH secretion?
when does it peak?
- main control is in hypothalamus via GHRH and GHIH (somatostatin)
- After onset of DEEP SLEEP
why is interuptted sleep in kids not good for them?
bc the levels of GH PEAK after onset of DEEP SLEEP.
so sleep is important for their growth
Pituatary tumors r Benign/malignant?
How do patients Clinically present?
what r the reasons that causes the symptoms?
Benign, they ain’t gunna kill ya
Either bc of the effect of the tumor mass on local structures
-Headache
-visual loss
OR
abnormality in pituitary function!
Hypo-hyper secretion
Explain the strucutres located around the pituitary gland.
Superiorly= optic chiasm
sides= Internal carotid artery, cavernous sinus
Inferiorly=
Describe what happens if u get an upwards growth of pituitary tumor?
Lateral growth?
up= it’ll squash the optic chiasm (where optic nerve cross over)= vision losss!
Bi-temporal heminopia
Lateral= effect nerves that control eye movement and pain
and cavernous sinus> they get 3rd nerve pasly and ptosis (droopy eye)
if u have a damage to ur pituary gland, what happens to your Prolactin levels?
goes up, bc usually the pituatry gland sends a negative control on prolactin.
so if its damaged> no negative control> high prolactin
when u get a pituatry tumor, what is the first hormone to be effected?
List in order the deficiencies in the hormones!
Growth hormone!
GH
LH/ FSH
TSH
ACTH
PRL
those with Gonadotropin deficiency, how to they present clinically? (men & women)
Men= got women feautures, no hair, wrinkly skin
Women= period stops ( women present earlier than men)
if youve got a lesion in the pituaitary that sqaushes the optic chiasm, how will your vision look like?
Bitemporal heminopia
what is the condition used to describe someone with large extremities? what causes this? how do they present (symptoms)?
what r the long term complications?
Diagnosis?
Treatments?
Any therpies available?
Acromegaly
is a disorder that results from excess GH in adults
Clinical findings
Large extremeties: Hands, feet, lower Jaw
Deep voice, large tongue w/ deep furrows
diaphoresis (excessive sweating)
impaired glucose tolerance (insulin resistence)
Long term complications:
- CVS death
- increased colonic cancer
- increased risk of thyroid cancer
- hypertension
- Diabetes
Diagnosis
- Oral glucose tolerance test (OGTT) w/ GH response
(Give glucose>> GH will not supress>> “failure to supress”
- Elevated serum IGF-1 levels (insulin like Growth factor)
Treatment?
Surgical removal of tumor! “trans-sphenoidal hypophysectomy” from nose
Tumours in cavernous sinus>> need additional treatment
1) reduce GH secretion
Dopamine agonists
Somatostatin analogs (octeroides)
2) blocks GH recepter
Pigvesomant
Radiotherapy
external beam
Gamma knife
what is the Cavernous sinus?
is a true dural venous sinus creating a cavity bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica.
What is cushings disease?
symptoms & findings?
Diagnosis?
Treatment?
Cushings>>Cortisol
increased cortisol
can be due to (ACTH-secreting pituitary tumour)
symptoms & findings
MOON face (we use cushion at night..lol)
Pink face, round abdomen
skinny weak arm and legs
thinning skin >Abdominal Striae (red stretch marks)
buffalo hump
Hypertension
Osteoporosis
describ ethese clinicnal findings, what can they be indication of?
Buffalo hump
Abdominal Striae (red strech marks)
Cushing disease!
what is the difference btw diabetes insipidous and diabetes Mellitus?
diabetes insipidous = caused by problems with a hormone called vasopressin (ADH). water is reabsorbed, pee alot!
pale”insipid” urine
diabetes Mellitus=occurs due to insulin resistance or insulin deficiency and subsequent high blood glucose levels.
“sweet urine”
Diabetes means “Siphon” is greek
it means water goes in (thirsty) and water goes out (pee alot)
just for fun guys
this is a siphon :P
coolio
How does vasopressin ADH work?
what inhibits it releases from the pitautry gland?
what controls the amount of ADH released?
it binds to Vasopressin recepter in kidneys
this facilittes TRASLOCATION of aquaporin channels allowing water reabsoeption into the blood.
Vasopressin= mean vasoconstrciton effects too on BV> ^ BP
OSMORECEPTERS in the hypothalamus detect changes in plasma osmolarity and control the amount of ADH released and thirst.
ALCOHOL
makes sense why drunk ppl wanna be so much ;p
what triggers oxytocin release?
suckling of breast> neurons from breast to hypothalamus> oxytocin released>gors to oxytocin recepters on myoepithelial cells surroundong mammalary alveoli>causes them to contract> squeeze milk into duct system.
childbirth>pressure on cervix and uterine wall> neurons to hypothlalamus>oxytoxin release> same shit but on uterine smooth muscle cells.
***Syntheic oxytocin (pitocin) is usually given after birth to increase uterine tone and control bleeding.***
explain the long loop & short loop feedback mechanisms involved in the regulation of GH. and explain what mediates each loop?
functions of cortisol!
- stimulates Gluconeogeneis
- bind to recepters on fat cells
- Supresses immune system
- increases liver pp
- depresses cartilgae and bone fomrmation
Adrenal gland hormones?
name procedure that can be used to remove pituatry tumor by inserting an endoscope through the nose
transsphenoidal surgery
