Hypothalamic Pituitary relationship and Biofeedback Pt1 Flashcards
Due to the anatomical location of the pituitary, what makes tumors in this area detremental
the expansion of the tumor can put pressure on the optic nerve and cause visual problems, dizziness
What connects the hypothalamus and the pituitary gland
the Hypophysial stalk
What are the anatomical names of the Anterior and posterior pituitary
Anterior pituitary is the (adenohypophysis)
-Epithelial portion of the pituitary
Posterior Pituitary (neurohypophysis) -Neural portion of the pituitary
WHat is the posterior pituitary derived from and what are the 2 nucleus that send axons here and what do they secrete
Derived from neural tissue
has axons from the Supraoptic nucleus and the Paraventricular nucleus
SON: secretes ADH
PVN: secretes Oxytocin
What does the anterior pituitary secrete and what connects the hypothalamus to the anterior pituitary
ACTH
TSH
FSH
LH
GH
Prolactin
connected to the hypothalams via the hypothalamic-hypophysial portal blood vessels
what are the connections between the hypothalamus and the posterior pituitary and the hypothalaums and the anterior pituitary
hypothalumus to the Posterior Pituitary: are neural
hypothalumus to the anterior Pituitary: are neural and endocrine
The hypothalamus releases what to act on what in the anterior pituitary that causes secretion of what hormone? TRH
hypothalamus releases thyrotropin releasing hormone (TRH)
act on the thyrotophs in the anterior pituitary
they release TSH Thyroid stimulating hormone
The hypothalamus releases what to act on what in the anterior pituitary that causes secretion of what hormone? CRF
Hypothalamus releases Corticotropin releasing hormone
act on the corticotrophs
they then secrete ACTH
The hypothalamus releases what to act on what in the anterior pituitary that causes secretion of what hormone? GnRH
Hypothalamus releases Gonadotropin releasing hormone
acts on the gonadotrophs in the anterior pituitary
release LH and FSH
The hypothalamus releases what to act on what in the anterior pituitary that causes secretion of what hormone? GHRH
hypothalamus releases Growth hormone releasing hormone
acts on the somatotrophs
release Growth hormone
The hypothalamus releases what to act on what in the anterior pituitary that causes secretion of what hormone? Somatostatin (GHIH)
hypothalamus releases Somatostatin
acts on somatotrophs
inhibits the release of Growth hormone
The hypothalamus releases what to act on what in the anterior pituitary that causes secretion of what hormone? PIF (dopamine)
Hypothalamus releases prolactin inhibiting hormone or dopamine
acts on the lactotrophs
inhibits the secretion of PRL or Prolactin
The hypothalamus releases what to act on what in the anterior pituitary that causes secretion of what hormone? TRH
Hypothalamus releases TRH
acts on the Lactotrophs
causes the release of PRL prolactin
what are the primary, secondary, and teritary disorders in the endocrine axis
primary endorine disorder: low or high levels of hormone due to a defect in the peripheral endocrine gland
Secondary endocrine disorder: low or high levels of hormone due to defect in the pituitary gland
Tertiary endocrine disorder: low or high levels of hormone due to defect in the hypothalamus
What are the 5 anterior pituitary axes
Hypothalamic-Pituitary-Gonad Hypothalamic-Pituitary-Liver Hypothalamic-Pituitary- Prolactin Hypothalamic-Pituitary-THyroid Hypothalamic-Pituitary-Adrenal
In males, what cells does LH act on, what does that cell release and what kind of feedback is generated
GNRH released by the hypothalamus which acts on the anterior Pituitary releases LH acts on Leydig cell
which then releases Testosterone
which serves as a negative feedback to the anterior pituitary and the hypothalamus
In males what does FSH act on, what does that cell release and what is the feedback generated
GnRH released by the hypothalalmus which acts on the Anterior pituitary releasing FSH
acts on sertoli cell which promotes spermatogenesis and releasing androgen binding protein
Inhibin is also released as a negative feedback on to the anterior pituitary
in females what does FSH and LH act on, what does that cell do and what is the feedback generated
the GnRH is released by the hypothalamus which acts on the pituitary which releases LH that acts on Theca cells releasing androgens
the FSH acts on the Granulosa cell to release progestins and estrogen
the negative feedback is the estrogen, inhibin, and progestins
unless their is ovulation then the enstrogen promotes a positive feedback
What is acromegaly
Rare disease
excessive growth of soft tissue cartilage and bone in the face hands and feet
cardiomegaly, organmegaly
hyperglycemia
due to prolonged and excessive secretion of growth hormone in adult life
What is the axes of Growth hormone
Hypothalamus releases GHRH
acts on somatotropes to produce GH
Targets the liver and the bone
at the liver it binds a GH receptor and creates a JAK-STAT signaling creating release of IGF-1 to promote growth
IGF-1 (somatomedin C) and Somatostatin (GHIH) serve as negative feedback on anterior pituitary
WHat are the direct actions of GH
binds directly to bones and muscle
Hypertrophy: increase size of cells
Hyperplasia: increase cell reproduction
increase glycogen and fat breakdown as well as increase of protein synthesis
What are the indirect actions of GH
signals to liver to produce IGF (insulin like growth factors)
targets every cell in the body
promotes hypertropy and hyperplasia
What is the function of ghrelin
Gastric fundal cells promote release of GH
What happens in a Growth hormone insensitivity and treatment
Lots of GH
but the liver is not producing very much IGF-1
therefore no negative feedback on GH
use Mecasermin
What happens in Secondary deficiency in the HPGh what is a treatment
No release of GH from the anterior Pituitary therefore low GH and Low IGF-1 but normal to high GHRH
use GH replacement: somatotropin, somatrem
What happens in Tertiary deficiency in the HPGh what is a treatment
lack of production of GHRH and Ghrelin from the hypothalamus therefore
low GH
low IGF-1
Normal Somatostatin
use Semorelin as treatment (mimics GHRH)
What is the Difference between Gigantism and Acromegaly
for Gigantism: excessive growth hormone before closure of bone epiphyses via IGF-1
for Acromegaly: excessive growth hormone after closure of bone epiphyses due to promotion of growth of deep organs and cartilaginous tissue
how does carbohydrate and protein intake impact Growth
sufficient carbohydrates and protein: liver will produce IGF-1 leading to Mitogenesis, lypolysis and differentiation
lack of protein: GH is inhibited and the liver wont produce IGF-1 leading to lipogenesis and Carbohydrate storage…weight gain
Lack of carbohydrates: increase GH and IGF-1 leading to Lipolysus, ketogenic metabolism, diabetogenic
due to GH raising blood glucose can lead to insulin insensitivity
how to diagnosis of Acromegaly
Delevated serum GH and IGF-1 levels
Failure to suppress GH production in response to an oral load of glucose
How does GH fluctuate during the day and through our lifetime
Primarily during sleep and peaks with exercise
also is elevated during childhood especially puberty
nonexistent in elderly years
What synthesizes Prolactin and when does this secretion begin,
Synthesized by the lactotropes and secretion begins to increase the 5th week of pregnancy
What does the prolactin suppress
GnRH which is used ti inhibit LH and FSH
therefore it suppresses the reproduction function and suppresses sexual drive
What are stimulatory factors of PRL
Pregnancy (estrogen) Breast feeding (suckling) Sleep Stress TRH
What are inhibitory factors of PRL
Dopamine
Dopamine agonists
Somatostatin
Prolactin via negative feedback
What is significant about a pituitary adenoma
they release an active hormone in excessive amounts into the bloodstream
What are the actions of Oxytocin
Milk ejection
Uterine contraction
-stimulated by dilation of cervix or orgasm
