Chapter 18 Endocrine Glands Part 2 Flashcards
what is the largest endocrine only gland
thyroid gland
how many hormones does the thyroid gland produce
3
what are the three hormones that the thyroid gland produces
T3
T4
calcitonin
what does the thyroid gland regulate
metabolism and cell growth and differentiation
what does the thyroid gland produce
heat
where is the location of the thyroid gland
anterior neck, inferior to larynx, with 2 lobes connected by narrow strip of tissue called isthmus
is the thyroid gland vascular or avascular
vascular- there are superior and inferior thyroid arteries
each thyroid gland contains follicles and is circular and surrounded by ?
simple cuboidal epithelium and filled with gel-like colloid material
what is the gel-like colloid material
thyroglobulin protein and iodine
what kind of cells are parafollicular cells
c cells
where are parafollicular cells located
between the follicles (clusters of cells)
what do parafollicular cells produce
calcitonin hormone
what does calcitonin regulate
blood calcium
what is calcitonin made by
parafollicular cells in thyroid
calcitonin is secreted in response to
increased blood calcium levels
where does calcitonin bind to
membrane-bound receptors
what does calcitonin decrease
osteoclast activity
calcitonin elongates what
life span of osteoblasts
calcitonin does bone deposit->
decreases blood calcium and phosphate levels
calcitonin opposed what
PTH
can our body make iodine
no you need to ingest it
thyroid hormone regulation has the hypothalamus that releases what to stimulate ant pit
thyrotropic-releasing hormone (TRH)
where is thyroid stimulating hormone released from
ant. pit
TSH stimulates the uptake of what
iodine
TSH incorporates what into what
iodine into thyroglobulin
the breakdown of thyroglobulin causes the
release of lipid soluble thyroxine (T4) and triiodothyronine (T3)
in the blood 75% of T3 and T4 is bound to
thyroxine-binding globulin (TBG)
regulation via neg feedback causes a decreased T3 stimulation of the hypothalamus to secrete what
TRH which stimulates the pituitary to secrete TSH
TSH is high when?
thyroid hormones are low
TSH is low when?
thyroid hormones are high (hyperthyroidism)
what is a disease from hyperthyroidism
grave’s disease
what is graves disease
autoimmune destruction of thyroid follicular cells- which mimics TSH and constant production of TH
excessive production of TH in graves disease means we will have low what and high what
low TSH
high T3 and T4
graves disease is due to
thyroid tumor or pit/ hypothalamic origin as well
hyperthyroidism symptoms
increased metabolism
high body temp with heat intolerance
weight loss, increased appetite
irritable, restless, insomnia
exopthalmos (graves)
hair fine, skin flushed/ moist
rapid HR/ BP
diarrhea
enlarged thyroid gland (goiter)
treatment for hyperthyroidism
beta blockers (help with increased beta-adrenergic tone)
anti-thyroid medications (PTU)
surgical removal of thyroid gland
radioactive iodine (destruction of thyroid tissue)
what is serve hypothyroidism
myxedema
what is congenital hypothyroidism
cretinism
what is hypothyroidism due too
diet (inadequate iodine intake)
chemical exposure
medications
hashimoto’s thyroiditis (autoimmune)
thyroid in origin
pit/ hypothalamic in origin
surgical removal of thyroid gland
inadequate dietary iodine causes
thyroid hypertrophy
goiter results from an
inability to synthesize adequate thyroid hormone
symptoms of hypothyroidism
decreased BMR, low body temp/ HR/BP
dry, cold skin with course hair
weight gain with reduced appetite
constipation
somnolence
goiter
weak skeletal muscles, apathy
treatment for hypothyrodism
replacement of thyroid hormone
levothyroxine (synthyroid)
what are parathyroid glands
4 glanded embedded on post. thyroid gland
what hormone does the parathyroid gland produce
parathyroid hormone (PTH)
the production and release of PTH by the parathyroid gland is regulated by
Chief cells
what does the parathyroid gland regulate
concentration of calcium in the blood
calcium levels control what is parathryoid gland
PTH production and release
high serum calcium does what for PTH release
inhibit
low serum calcium does what for PTH release
triggers
calcitonin (produced in parafollicular/ c cells) decreased
blood calcium levels
how do we control blood calcium
2 hormones work antagonistically
rising blood calcium levels generate what
increase in calcitonin production
rising blood calcium levels generate an increase in calcintonin production which causes what
a decrease in activity of osteoclasts in relation to osteoblasts
a decrease in activity of osteoclasts in relation to osteoblasts remove what from the blood and deposit it where
calcium from the blood and deposit in the bone
calcitonin also diminshes calcium uptake in what?
the gut
falling blood Ca levels generate an increase in what production
PTH
falling blood Ca levels generate an increase in PTH production which causes an increase in
osteoclast activity releasing calcium from bone and increasing blood calcium concentration
what increase Ca uptake in the gut
PTH
usually see low Ca and low phosphate together is what
hypercalcemia
patients with hypercalcemia will have
bone fractures and weak bones
renal stones
heart and brain dysfunction
what can hypercalcemia be from
overactive parathyroid glands
what is hypocalcemia commonly a result from
too much Ca lost in urine when not enough Ca moved from bones to blood stream
causes of hypocalcemia
low levels of PTH
