Basic Info Flashcards
thyroid gland
2nd most common endocrine organ to have pathology
where is the thyroid gland located?
in the neck
what does the thyroid gland release?
- thyroid hormone (TH) made from thyroglobulin and contain iodine
- calcitonin
T3 and T4
triiodothyronine and thyroxinr; T4 is converted to T3 (biologically active form of TH)
what does the TH target?
most cells in body to increase metabolic rate
-increase protein/fat/CHO metabolism, heat production, HR –> tachycardia
too much TH leads to
hyperthyroidism and grave’s disease
too little TH could be due to
dietary iodine deficiency, congenital
what cells secrete TH?
follicle cells
what is the role of calcitonin?
targets bones and kidneys to decrease Ca levels in the blood (by inhibiting osteoclast activity and increasing excretion Ca in the urine)
what cells secrete calcitonin?
C cells aka parafollicular cells
what is a goiter?
enlarged thyroid gland
what causes a goiter?
hyperthyroidism and hypothyroidism
what function does an endemic goiter have?
hypofx
why do endemic goiters have hypofx?
d/t deficiency of iodine
what is converted to what which is needed for TH synthesis?
iodide is converted to iodine
what happens with deficiency of iodine?
TH is made, but has a decreased fx, which stimulates the ant pit to release TSH
what does the release of TSH from the ant pit cause in a deficiency of iodine?
causes hyperplasia and hypertrophy of the thyroid gland
what is the function like with a toxic goiter?
hyperfx
what happens with production of TH in a toxic goiter?
there is excess prod of TH, that do not rely on stimulation from TSH
what does the gland look like with a toxic goiter?
gland appears nodular (bumps felt on palpation, seen on imaging)
what is the cause of hyperthyroidism?
autoimmunity
Grave’s disease
85% of all hyperthyroidism
what gender has a higher prevalence of grave’s disease?
women; onset at age 20-40
what are the hallmarks of grave’s disease?
- hyperthyroidism
- goiter
- exophthalmos = protruding eyeballs (d/t fluid accumulation in fat pads and orbitus muscle in eye OR excessive retraction of eyelids)
what does the hypothalamus synthesize?
oxytocin and ADH and send those to the posterior pituitary
what other hormones does the hypothalamus send and where to?
inhibiting or releasing hormones to the pituitary gland to either suppress or stimulate the release of hormones
the inhibiting and releasing hormones depend on what to be released?
the demand for hormones, which is communicated via negative feedback
what does the posterior pituitary release?
ADH and oxytocin
what does the anterior pituitary synthesize and release?
own hormones such as TSH and ACTH (adrenocorticotropic hormone)
what do TSH and ACTH stimulate?
respective target organs to prod hormones which then signals back to pituitary and hypothalamus to stop releasing TSH and ACTH in negative feedback loop
