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36 terms

Endocrine: part 1

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Endocrine System
hormones that act on cells distant from site of synthesis
increased activity of target tissue down regulates activity of gland (feedback inhibition)
hormone classification
based on nature of their receptors
lactotroph
prolactin (PRL)
mammary glands (production of milk)
produced by anterior pituitary gland
somatotroph
secrete growth hormone
somatomedins: stimulate growth
produced by anterior pituitary
corticotroph
synthesize pro-opiomelanocortic (POMC), which splits into:
corticotropin (ACTH)
b-lipotrophin
anterior pituitary
thyrotrophs
produce thyrotropin (TSH)
anterior pituitary
hyperfunction of pituitary gland
excess production of anterior pituitary hormones is most often caused by anterior pituitary adenoma
classification of adenomas
functional=pt will have symptoms
silent=pt will have no symptoms
anterior pituitary adenoma
3% of cases are associated with MEN1
macroadenoma
microadenoma
common genetic alteration associated with adenoma (GNAS1 gene)
10% of cranial neoplasms
prolactinoma
hyperprolactinemia
chromophobic
small microadenomas to large, expansile tumor
large, nonfunctional until size increased and starts compressing other brain structures

ameonorrhea, galactorrhea, loss of libido, infertility
hyperprolactinemia
women: ammenorrhea, galactorrhea, infertilitiy
men: loss of libido, galactorrhea
sign: peripheral vision loss
causes: hypothalmic lesions, meds, hypothyroidism
Somatotropic adenoma aka growth hormone adenoma
2nd most common pituitary tumor
40% have activating mutations in the GNAS1 gene on chromosome 20q13
hypersecretion of GH
acidophilic
hyperproduction of somatomedins (somatomedin C)

gigantism, acromegaly, impaired glucose tolerance, diabetes mellitys
growth hormone excess
abnormal glucose tolerance
generalized muscle weakness
hypertension
arthritis
osteoporosis
congestive heart failure
clinical: gigantism
acromegaly
gigantism
hypersecretion of growth hormone prior to closure of growth plate
acromegaly
hypersecretion of growth hormone after the closure of growth plates
enlarged jaw (pronathism), sausage fingers
corticotropic adenoma
small at time of dx
hypersecretion of ACTH (stimulates adrenal gland to produce cortisol)
cushings disease/syndrome
hyperpigmentation
cushings disease/syndrome
disease: pituitary adenoma-ACTH hypersecretion
basophilic (mostly)
sometimes multiple microadenomas
syndrome: increased cortisol due to any cause
symptoms of cushings
buffalo hump
hypertension
thinning of skin
moon face with red cheeks
increased abdominal fat
osteoporosis
increase susceptibility to obesity
apple like appearance
could be misdiagnosed as a psych condition
anterior pituitary hypofunction
hypopituitarism
congenital or acquired
causes: non-secretory pituitary adenomas
ischemia necrosis of pituitary (sheehan syndrome)
ablation of the pituitary by surgery or radiation
growth hormone deficiency
pituitary dwarfism
gonadotropin or gonadotropin realeasing hormone deficiency
adults
symptoms: loss of libido, ammenorrhea, loss of secondary sex characteristics, infertility, increased insulin sensitivity
deficiency of ACTH
secondary adrenal failure: no hyperpigmentation of skin
lack of ACTH & beta melanocyte stimulating hormone; hypopigmentation
primary adrenal failure: failure of gland itself
increase of ACTH & beta melanocyte hormone; hyperpigmentation
posterior pituitary
nuerohypophysis
modified glial cells & axonal processes from erve cell bodies in supraoptic and paraventricular nuclei of hypothalamus
hormones: synthesized in hypothalamus neurons
stored and transported via axons to post. pit.
oxytocin
ADH
oxytocin
smooth muscle contraction
uterus, lacterious ducts
ADH
water reabsorption by collective tubules of kidney; antidiuretic
SIADH
Syndrome of Inappropriate Antiduretic Hormone
most common is from secretion from an ectopic source:
tumors, retention of H20, increase in total body water
Na levels decrease
cerebral edema and neurologic impairment
deficiency of ADH
diabetes insipidus-central vs. nephrogenic
central: ADH not being released by pituitary
nephro: kidney tissue not recognizing ADH even though it is being secreted properly by pituitary
causes: trauma, tumors, inflammatory process, surgical procedures
polyuria & thirs due to excreting large amounts of diluted urine
thyroid hormones
thyroxine (T4)
triiodothyronine (T3)
both bound to thyroid binding globulin (TBG)
iodine required for synthesis of thyroid hormone
thyroglobulin: storage
TSY (thyrotropin) feedback
goiter
impaired synthesis of thyroid hormone
rise in TSH causes hypertrophy and hyperplasia of thyroid follicular cells
gross enlargement of thyroid gland
size of goiter is proportional to severity/length of thyroid deficit
capable of producing T4, T3
causes of goiter
physiologic enlargement: puberty, pregnancy
iodine deficiency
hasimoto's thyroiditis
Dyshormonogenesis: failure of thyroid hormone synthesis
types of goiter
toxic goiter: hyperthyroidism (plummer syndrome) hyperfunctioning toxic nodule, no eye bulging, no dermatopathy
nontoxic goiter (diffuse): euthyroid or hypothyroid. diffuse grave's disease; eye bulging
endemic goiter (diffuse): iodine deficient. directly related to iodine deficiency
Thyroid neoplasms
folicular adenomas
papillary carcinoma
medullary cancer
anaplastic carcinoma
thyrotoxicosis (hyperthyroidism)
hpermetabolic state and overactivity of sympthetic nervous system
heat intolerance, weight loss, increased appetite, diarrhea, restless, irritable, proximal muscle weakness, tremors, tachycardia, wide staring gaze, small scant menses, thin hair
grave's disease (diffuse toxic hyperplasia)
thyrotoxicosis
infiltrative opthalmopathy
infiltrative dermopathy
women 7x>men
genetic component
autoimmune
diffuse hyperplasia of thyroid (smooth and symmetric)
opthalmology (wide staring gaze and lid lag): increased adipose tissue behind the orbital space
pretibial edema
hypothyroidism
intrinsic abnormailty in the thyroid or results from hypothalamic or pituitary disease
cretinism (infancy/early childhood)
myxedema (adolescents/adulthood)
cretinism
infancy/early childhood
iodine deficiency
deficiency of enzymes to synthesize thyroid hormones
failure of fetal thyroid to descend from origin
anti-thyroid antibodies from mother to fetus
impaired development of skeleton and nervous system
myxedema
women>men
generalized apathy and mental sluggishness
cold intolerance
weight gain
deepened voice
constipation
menorrhagia
dry skin
hair loss
hypoactive deep tendon reflexes