Week 2- Thyroid and Adrenals Flashcards
is a normal thyroid visible?
no
The thyroid gland is composed of follicles composed of ____________
follicular cells
follicular cells in the thyroid secret
thyroid hormone
hormone cascade thyroid
-Hypothalamus releases TRH
-Anterior Pituitary releases TSH
-TSH binds with TSH receptor sites located on the plasma membrane of the thyroid follicular cells
-Thyroid makes T3 and T4
Effects of TSH on Thyroid
-increase ease in the release of stored thyroid hormones
-Increase in iodide uptake and oxidation
-Increase in thyroid hormone synthesis
-Increase in the synthesis and secretion of prostaglandins by the thyroid.
-Stimulating the growth and maintenance of the thyroid gland by stimulating thyrocyte hypertrophy and hyperplasia and decreasing apoptosis.
The thyroid gland normally produces how much T3 vs T4
90% T4 and 10% T3
T3 and T4 are primarily transported bound to one of three carrier proteins:
- thyroxine binding globulin (TBG)
- thyroxine-binding prealbumin (transthyretin)
- albumin
In the body tissues, T4 is converted to T3 by a_________ dependent process
-what mineral
selenium
another name for hyperthyroid
thyrotoxicosis
Primary hyperthyroidism causes
include Graves disease, toxic multinodular goiter, a solitary toxic adenoma and, very rarely, follicular thyroid carcinoma
Central (secondary) hyperthyroidism is less common and is caused by
TSH-secreting pituitary adenomas
hyperthyroid sxs
-increased metabolic rate
heat intolerance
increased tissue sensitivity to stimulation by the sympathetic division of the autonomic nervous system
Diarrhea, heart palpitations, warm skin/sweaty palms, anxiety
hyperthyroid tx
-antithyroid drug therapy (methimazole or propylthiouracil)
- radioactive iodine therapy
-surgery
A major complication of all forms of treatment for hyperthyroidism is hypothyroidism.
autoimmune hyperthyroid
graves disease
in graves disease is TSH production stopped
Yes… but the antibodies are still bound to the thyroid receptors hence the thyroid keeps making hormones
Graves sxs
Increased secretion of hyaluronic acid, orbital fat accumulation, inflammation, and edema of the orbital contents result in exophthalmos (protrusion of the eyeball). Periorbital edema and extraocular muscle weakness lead to diplopia (double vision).
pretibial myxedema (Graves dermopathy)
subcutaneous swelling on the anterior portions of the legs and by indurated and erythematous skin
Thyrotoxic Crisis - “Thyroid Storm
-death can occur within 48 hours
-hyperthermia; tachycardia, especially atrial tachydysrhythmias; high-output heart failure; agitation or delirium; and nausea, vomiting, or diarrhea, contributing to fluid volume depletion.
myxedema
happens in severe long term hypothyroid
-swelling of the skin/tissues
-waxy appearance
myxedema sxs
Non-pitting, boggy edema, especially around the eyes, hands, and feet and in the supraclavicular fossae. Myxedema is also responsible for thickening of the tongue and the laryngeal and pharyngeal mucous membranes. This results in thick, slurred speech and hoarseness, both of which are common in hypothyroidism.
Levothyroxine is only ____. Desiccated thyroid (Armour thyroid, NP Thyroid, Nature Throid) contains both T4 AND T3 (the active form of thyroid)
T4
gradual inflammatory destruction of thyroid tissue by infiltration of lymphocytes and circulating thyroid autoantibodies (antithyroid peroxidase and antithyroglobulin antibodies - Anti TPO Antibodies, Anti TG Antibodies)
gradual inflammatory destruction of thyroid tissue by infiltration of lymphocytes and circulating thyroid autoantibodies (antithyroid peroxidase and antithyroglobulin antibodies - Anti TPO Antibodies, Anti TG Antibodies)
The parathyroid glands produce parathyroid hormone (PTH), which works in concert with vitamin D to__________ serum calcium concentration and decrease __________-
increase calcium
decrease phosphate
In the kidneys, PTH acts on its plasma membrane receptor in the distal tubules of the nephron to increase reabsorption of calcium
In the kidneys, PTH acts on its plasma membrane receptor in the distal tubules of the nephron to increase reabsorption of calcium
Hyperparathyroidism
greater than normal secretion of parathyroid hormone (PTH) and hypercalcemia
hallmarks of primary hyperparathyroidism.
Hypercalcemia and hypophosphatemia
-high calcium
-low phosphorus
-80% to 85% of cases are caused by parathyroid adenomas
Hypoparathyroidism (abnormally low PTH levels) most commonly is caused by
damage to the parathyroid glands during thyroid surgery
hypoparathyroid labs
decrease calcum
increase phosphate
hypoparahyroid sxs
-hypocalcemia sis
-This creates tetany manifested as muscle spasms, hyperreflexia, tonic clonic convulsions, laryngeal spasms, and, in severe cases, death from asphyxiation
Chvostek sign is elicited by
tapping the cheek, resulting in twitching of the upper lip
-associated with hypocalcemia
-hypoparathyroid
Trousseau sign is elicited by
-inflate BP cuff to a level above the systolic blood pressure
-leads to a painful carpal spasm.
Chvostek and Trousseau signs are used for what disorder
hypoparathyroid
In effect, each adrenal gland functions like____- separate glands
two
80% of the adrenal gland is the adrenal _________
cortex
3 zones of adrenal cortex
-
zona glomerulosa SALT
-the outer layer
-produces the mineralocorticoid aldosterone. -
zona fasciculata SUGAR
-the middle layer
-is 78% of the cortex and -secretes the glucocorticoids cortisol, cortisone, and corticosterone. -
zona reticularis SEX
-inner layer
-secretes mineralocorticoids (aldosterone), adrenal androgens and estrogens, and glucocorticoids.
The cells of the adrenal cortex are stimulated by the anterior pituitary hormone _____
ACTH (Adrenocorticotropic)
glucocorticoid have direct effects on _________ metabolism
carbohydrate
increase blood glucose concentration by promoting gluconeogenesis in the liver and by decreasing uptake of glucose into muscle cells, adipose cells, and lymphatic cells
glucocorticoid
In extrahepatic tissues, the glucocorticoids stimulate ______________ and inhibit _________________
stimulate protein catabolism and inhibit amino acid uptake and protein synthesis
complications of the use of glucocorticoids in the treatment of disease
infection
poor wound healing
secretion of cortisol is regulated primarily by the __________-
hypothalamus and the anterior pituitary gland.
Three factors that regulate the secretion of ACTH:
- negative feedback with cortisol in the system
- diurnal rhythms affect ACTH and cortisol levels- cortisol peaks just before awakening
- psychologic and physiologic stress increase cortisol levels
acts to conserve sodium by increasing the activity of the sodium pump of the epithelial cells in the nephron.
aldosterone
Aldosterone synthesis and secretion are regulated primarily by the
renin-angiotensin aldosterone system (RAAS)
renin-angiotensin system is activated by
sodium and water depletion, increased potassium levels, and a diminished effective blood volume
renin-angiotensin system is activated by
sodium and water depletion, increased potassium levels, and a diminished effective blood volume
causes an increase in salt and water reabsorption into the bloodstream from the kidney thereby increasing the blood volume, restoring salt levels and blood pressure
aldosterone
what cells secrete the catecholamines epinephrine (adrenaline) and norepinephrine,
Chromaffin cells (pheochromocytes)
epinephrine and norepinephrine are made from
amino acid phenylalanine
how long do the catecholamines remain in the blood stream
seconds to minutes
refers to the complex of clinical manifestations resulting from chronic exposure to excess cortisol
cusshings syndrome
overproduction of pituitary ACTH by a pituitary adenoma
cusshings disease
excess ACTH stimulates excess production of cortisol and there is loss of feedback control of ACTH secretion
ACTH-dependent hypercortisolism
ACTH-independent secreting tumors of the adrenal cortex
tumor on adrenal cortex makes cortisol
in what syndrome
-increases in bone resorption lead to
osteoporosis and can result in pathologic fractures,
cusshings
Abnormal dexamethasone suppression test with Cushings
dexamethasone= synthetic cortisol
-cortisil production should go down after receiving drug, but it stays high in cusshings
antibodies for hashimotos
thyroid peroxidase ab (TPO ab)
thyroglobulin ab (TG ab)
antibodies for graves
thyroid stimulating immunoglobulins (TSI antibodies)
-binds to receptor leads to high thyroid levels
what does aldosterone do
-increase sodium retention
-increase BP
-increase blood volume
