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Flashcards in thyroid Deck (31):
1

what is the body's largest wholly endocrine gland?

thyroid gland

2

what is the most important function of the thyroid gland?

basal metabolism regulation

3

is the thyroid gland normally palpable?

no!

4

what is the term for palpable enlargement of the thyroid?

goiter

5

what cells contain iodide?

follicular cells of the thyroid

6

what cells secrete calcitonin?

parafollicular cells

7

what cells synthesize and secrete thyroglobulin?

follicular cells

8

what cells secrete T3 and T4?

follicular cells

9

what is the role of calcitonin?

ca++ and phosphorus metabolism
-decrease blood [ca++]
-increase urinary loss of ca++

10

what is the thyroid's blood supply like?

it has the greatest blood flow per gram of tissue in the body

11

regulation of the thyroid gland is _____ dependent.

pituitary dependent

12

hormone regulation for the thyroid:

TRH (hypothalamus) -> TSH (pituitary) -> T3,T4 (thyroid)

13

what do vacuoles in the colloid indicate>

that the follicle is active

14

what is needed for the synthesis of thyroid hormone?

iodine

15

what are the 3 steps to liberation of T3 + T4??

-endocytosis by thyroid epithelial cells (colloid contains thyroglobulin)
-lysosomes fuse with endocytotic vesicles (lytic enzymes free thyroid hormones)
-free thyroid hormones diffuse from lysosomes, out of cell and into blood

16

how to thyroid hormones travel through the blood to target cells?

carrier proteins

17

which thyroid hormone is a prohormone?

T4 ->T3

18

is there more T3 or T4 in the blood?

there is 20X more T4 than T3 in the blood

19

T3/T4 breadown are de-iodinated and decarboxylated to become what?

thyronine

20

what is the parafollicular hormone?

calcitonin

21

what type of hormone is calcitonin?

poly-peptide hormone

22

what are the actions of calcitonin on osteoclasts and the kidneys?

-osteoclasts: blocks osteoclasts action (inhibits bone resorption)
-kidneys: blocks renal reabsorption of calcium and phosphorus

23

what is calcitonin's action on PTH?

antagonistic

24

what causes goiter 90% of the time?

iodine deficiency

25

goiter is a sign of?

hyperthyroidism

26

what are other signs of hyperthyroidism?

-goiter
-heat insensitivity
-unkempt coat
-eye sign
-tachycardia
-weight loss

27

how can you test borderline hyperthyroid cases?

-differentiated by TSH stimulation test
-tumors aren't stimulated by TSH
-thyroid scan

28

treatment for hyperthyroidism

-antithyroid drug
-radioactive idodine
-surgery

29

what disease is a deficiency of thyroid follicular hormones?

hypothyroidism

30

clinical signs for hypothyroidism

-elevated canine thyroglobulin auto-antibodies (detects autoimmune disease)
-alopecia on tail
-lethargy
-cold intolerance
-weight gain
-hyperpigmentation of skin

31

what is the treatment for hypothyroidism?

synthetic T4