Final exam Flashcards
mass effect
non-function and exert local pressure on gland or surrounding tissue, which can interrupt or alter function or slowly crush the tissue out of existence
effect of a growing mass that results in secondary pathological effects by pushing on or displacing surrounding tissue.
negative feedback loop
secreting hormones stimulate a target organ, which in turn secrets its own hormones to achieve the desired end effect
negative feedback loop organs (pituitary gland)
adrenal glands, thyroid, ovary, testies, release their own hormones for a final effect, these hormones in turn interact with the pituitary gland in a negative feedback loop
adrenal cortex
located on the tops of the kidneys, the outer cortex of the adrenal gland
secretes corticosteroids:
◦ mineralocorticoids- primarily aldosterone; secreted by the zona glomerulosa, they act on the kidney to retain sodium and water and excrete k+, actions that increase blood volume and regulate blood pressure
◦ glucocorticoids, mainly cortisol; secreted by the zona fasciculata
‣ increase glucose production
‣ stimulate the degradation of protein into amino acids and fat into fatty acids
‣ inhibit peripheral glucose utilization to ensure that adequate glucose is available for the brain
‣ suppress immune reaction and limit inflammation
◦ sex steroids
‣ estrogens and androgens, less potent than those secreted by the ovaries and testes
adrenal medulla
directly connected by nerve fibers of the autonomic nervous system
secretes hormones that act on cardiac muscle, smooth muscle, and glands to control involuntary functions such as heart rate, blood pressure, sweating, and bowel peristalsis
• formed of chromaffin cells: neuroendocrine cells derived from embryologic neural crest that develops into brain and peripheral nerves
• chemoreceptors sensitive to pH and oxygen tension in the regulation of respiration
• chromaffin cells secrete catecholamines, chemicals that act in various ways to help the body adapt to sudden stress
• epinephrine
◦ simulates heart rate
◦ dilated bronchioles
◦ coronary arteries
◦ constricts peripheral blood vessels
◦ increases mental alertness and respiratory rate
◦ increases metabolic rate
• norepinephrine
◦ powerful effect causes constriction of small blood vessels, increasing peripheral resistance and raising blood pressure
tumors can cause overproduction of catecholamines
parathyroid
not under control of pituitary gland
rather their output of parathyroid hormone (PTH) is controlled by the level of free ionized blood calcium
Regulates calcium homeostasis in a negative feedback loop with free calcium
• tumors-> usually lead to hypercalcemia due to increased PTH
DI
Diabetes insipidus
Hypofunction of the posterior pituitary: vasopressin deficit
excessive production of dilute urine
‣ high Na+
‣ high blood serum osmolality
head trauma, inflammatory disorders of the brain or pituitary, tumors, or pituitary surgery
‣ can also be nephrogenic DI
‣ low urine specific gravity
30% idiopathic 25% brain tumors 20% surgical tx of brain tumors 16% brain trauma 9% hypophysectomy
TX: desmopressin (DDVAP) monitor urine specific gravity, adequate fluid intake
SIADH
Hyperfunction of posterior pituitary: vasopressin excess
syndrome of inappropriate ADH secretion
‣ associated with excessive ADH production, usually from nonpituitary neoplasm
‣ brain, pulmonary and endocrine disorders
‣ hyponatermia and cerebral edema
tx: eliminate cause, correct volume blood abnormalities
euthyroid sick syndrome
patients with severe nonthyroidal illness may have abnormally low thyroid function tests but are clinically euthyroid
SICK, hospitalized patient that develops low thyroid test
Thyrotoxicosis
A hyper metabolic state caused by excess thyroid hormone- increased levels of T3 + T4 (no matter the source)
• lid lag
• heat intolerance
• overactive metabolism
• tachycardia
‣ diffuse glandular hyperplasia
• usually graves disease
‣ multi-nodular goiter with overproduction of hormones
‣ adenoma of the thyroid with overproduction of hormones t3
‣ speeds up cells metabolic rate
‣ increases cardiac output
‣ activates sympathetic nervous system
diagnosis
‣ measuring TSH, T3, T4
• primary cause->TSH will be low and unbound thyroid hormones will be high
‣ radioactive iodine uptake test
thyroid storm
state of severe hypermetabolism
graves disease
autoimmune disease caused by the production of multiple antithyroid antibodies
IgG autoantibodies (TSI) bind to and stimulate TSH recepors on thyroid
◦ most often affects women
◦ can be accompanied by other autoimmune diseases
◦ clinical findings
‣ hyperthyroid goiter due to diffuse thyroid hyperplasia
‣ pretibial infiltrative dermopathy
‣ ophthalmopathy
• exophthalmos (globe pushed forward)
- lab findings: increased T4/T3 levels and low TSH (make less!)
hypothyroidism
Underproduction of thyroid hormones by the thyroid gland
more common than hyperthyroidism
women more often affected
◦ primary- disorders within the gland
◦ secondary- disorders affecting pituitary or hypothalamus
◦ primary hypothyroidism-> due to thyroid gland problems (more common!) congenital, acquired, or autoimmune
- iodine deficiency
- hashimoto thyroiditis- autoimmune disorder
cretinism
hypothyroidism in children
congenital often caused by iodine deficiency in pregnancy
or genetic defects
myxedema
hypothyroidism that develops in the older child or adult
‣ thick myxomatous fluid in various organs
‣ bags under eyes, puffy eyelids, swollen tongue, edema of vocal cords and hoarseness, swelling of the hands and feet, pleural and pericardial effusions, weight gain, skin is cool and pale
‣ cold intolerance
Hashimoto thyroiditis
‣ chronic autoimmune disease, is by far the most common type of thyroiditis, hypothyroidism and goiter int he united states
‣ nontoxic goiter and almost elusively in mid aged women
‣ antithyroid antibodies and cytotoxic t cells destroy thyroid epithelial cells
‣ causes mild hypothyroidism
‣ patients are at risk to develop nonhodgkins lymphoma
tx: lifetime hormone replacement therapy with L-thyroxine
subacute granulomatous thyroiditis
‣ less common then Hashimoto
‣ may be associated with viral infections (URIs)
‣ much of reserve is released through inflammatory process, patients may become thyrotoxic for a short period of time as thyroid hormones are washed out of inflamed gland
goiter
is an enlarge thyroid gland. describes only the size of the gland and does not indicate anything about thyroid function or pathology
Cushing syndrome
adrenalcortical hyperfunction: clinical s/s that result from excessive amt of blood glucocorticoid, usually cortisol
exogenous (from glucocorticoid therapy) or endogenous
‣ the most common cause is exogenous glucocorticoid medical therapy
• medications mimic action of cortisol on tissue
• negative feedback, which shuts down
Primary: adrenal tumor Secondary: Pituitary adenomas=Cushing
disease( Ectopic ACTH production)
Tertiary – Hypothalamus malfunction
• Exogenous corticosteroid use
ACTH= usually produced by pituitary gland and controls the production of cortisol
s/s: htn, obesity, round (moon) facial features, DM, skin marks striae, excess body and facial hair (hirsutism), muscle wasting, bone demineralization, mensural and mental abnormalities.
adrenocortical hyperfunction, aldosterone effects, and androgen effects
labs: cortisol levels; plasma and urinary
tx: surgery (unilateral adrenalectomy), cortisol-blocking medications, weaning exogenous steroids as able
congenital adrenal hyperplasia
‣ congenital disorder of sexual differentiation that arises from one of the sever varieties of autosomal ressevice genetic defects that cause cortical enzyme deficiency, androgen excess, congenital adrenal hyperplasia
‣ 21 b-hydroxylase deficiency
‣ aldosterone deficiency and salt wasting
Addison disease
primary cortical failure-> deficiency in all 3 corticosteroids (cortisol, aldosterone, and sex steroids)
Primary:
◦Destruction of gland:
idiopathic, autoimmune, trauma, neoplasia
almost all cases attributed to: autoimmune adrenalitis, TB, AIDs, or metastatic carcinoma
Inability to adjust to
stress
◦Hypoglycemia
◦Weight loss
Insufficient
aldosterone
◦Low blood pressure
◦Weakness
◦Hyperkalemia
◦Hyponatremia
Increased ACTH
◦Hyperpigmentation
• tx- corticosteroid replacement/ lifetime cortisol replacement
addisons disease is rare
pheochromocytomas
‣ rare neoplasm of the adrenal medulla
‣ severe HTN- most important clinical sign
‣ benign tumors are surgically removed
produce catecholamines
s/s headache, tachycardia, diaphoresis
dx: ct scan- to see tumor?
tx: surgical removal of tumor
also..
◦ paragangliomas
‣ other neurogenic tumors that arise from chromaffin cells in the medulla or paraganglion system
hyperparathryroid
oversecretion of PTH by the parathyroid glands
‣ primary- parathyroid hyperplasia or adenoma
‣ secondary and teriary overactivity are due to chronic renal failure
‣ classical findings stones, bones, groans with psychiatric overtones
• kidney stones
• destructive bone changes and osteoporosis
• groans is peptic ulcers, pancreatitis, or gallstones that occur in some cases
• psychiatric overtones
◦ depression and fatigue
hypoparathyroid
low blood calcium and PTH levels