thyroid gland

Question 1

the internal structure of the thyroid gland is a series of ____ formed by spheres of _____ and filled with _____

Answer 1

hollow follicles; epithelial cells; colloid

Question 2

the apical surface of the epithelial layer faces the ____ ; the basal surface faces the _____

Answer 2

colloid; blood supply

Question 3

epithelial cells are also called _____, and these cells regulate the production of two ____

Answer 3

follicle cells; iodine-containing thyroid hormones

Question 4

thyroid hormones are ____ and thus cannot be stored in _____

Answer 4

lipophilic; secretory vesicles

Question 5

thyroid hormone is synthesized ____ in the colloid and can be stored in the _____

Answer 5

extracellularly; colloid

Question 6

iodide is transported across the basal side of the follicle cells via a _____

Answer 6

Na/I transporter

Question 7

follicle cells also synthesize a large, tyrosine rich protein called _____, and the enzyme _____; both proteins are exocytosed across the apical membrane into the colloid

Answer 7

thyroglobulin (TG); thyroid peroxidase

Question 8

bind of ___ to ____ maintains the concentration gradient needed to continuously sequester iodide in the colloid

Answer 8

iodide; thyroglobulin

Question 9

receptors for TH are in the ____ of most cells of the body, and there are ___ different receptor subtypes

Answer 9

nuclei; four

Question 10

expression of the receptor isoforms differs with respect to ____ and ____

Answer 10

stage of development; target tissue

Question 11

receptors occupied by TH will _____ and form a _____ that regulates gene transcription

Answer 11

dimerize; dna binding protein

Question 12

the principle effect of TH is to ____

Answer 12

stimulate cellular metabolism

Question 13

TH increases

Answer 13

• Na/K ATPase activity
• synthesis of respiratory enzymes
• substrate availability
• cellular heat production

Question 14

TH stimulates increase in number and size of ____

Answer 14

mitochondria

Question 15

TH induces upregulation of _____ that are critical for responses to activation of the sympathetic NS; increases sensitivities to ____ in both the endocrine and nervous systems

Answer 15

beta-adrenergic receptors; catecholamines

Question 16

TH regulates production of _____ and is important for _____

Answer 16

growth hormone (GH); CNS development and function

Question 17

hypothyroidism most often caused by a _____ in the thyroid gland; 95% of cases involve an ____ or _____ that prevents it from making TH

Answer 17

primary defect; iodine deficiency; damage to the gland

Question 18

without iodine, there is _____ and lack of _____ increases secretion of ___ and ____ leading to growth of a goiter

Answer 18

insufficient production of TH; negative feedback; TRH; TSH

Question 19

other primary defects leading to hypothyroidism

Answer 19

• autoimmune thyroiditis or Hashimoto’s thyroiditis
• damage or destruction of the gland
• dysfunction assoc with other illness

Question 20

consequences of iodine deficiency during prenatal development range from ____ deficiency to ____, ___, r _____

Answer 20

moderate; cretinism; miscarriage; stillbirth

Question 21

secondary defects in hypothyroidism arise from deficits in ____ or ____ synthesis and release, or receptor deficits; in other words, the gland is not receiving proper _____

Answer 21

TRH; TSH; stimulatory input

Question 22

symptoms of mild hypothyroidism include ____ and ____

Answer 22

sensitivity to cold; slight weight gain

Question 23

symptoms of moderate hypothyroidism are due to the effects of reduced ____ receptors and the disruption of responses to _____ stimulation

Answer 23

beta-adrenergic

catecholaminergic

Question 24

condition associated with severe hypothyroidism; severe bloating due to accumulation of glycosaminoglycans in the extracellular/interstitial fluid, typically most obvious in the face

Answer 24

myxedema

Question 25

____ is an autoimmune disease that is a common cause of hyperthyroidism

Answer 25

graves disease

Question 26

type of hyperthyroidism that results from consuming excess thyroid hormone either in medication or inappropriately processed meat

Answer 26

thyrotoxicosis factitia

Question 27

secondary defects causing hyperthyroidism include tumors that secrete ____ without responding to feedback control by ___

Answer 27

TSH; TH

Question 28

treatment for hyperthyroidism includes ____ or _____

Answer 28

surgical removal of the gland; destruction using radioactive I

Question 29

several antithyroid drugs act to inhibit ____, block the release of ____, or ameliorate the effects of TH in _____

Answer 29

iodination of tyrosine; TH; peripheral tissues

Question 30

cretinism is assoc with retarded _____ and _____

Answer 30

tooth development; maxillary prognathism

Question 31

disease in which the body produces Ab that interferes with TH synthesis

Answer 31

autoimmune thyroiditis or Hashimoto's thyroiditis (type of hypothyroidism due to primary defect)

Question 32

treatment for hypothyroidism due to lack of thyroid hormone

Answer 32

exogenous TH

Question 33

goiter develops if hypothyroidism is due to a ____ defect

Answer 33

primary (due to lack of negative feedback)

Question 34

goiter can develop in cases of _____ caused by hyperstimulation of the ____, even though TSH levels are low

Answer 34

graves disease; TSH receptor

Question 35

symptoms of hyperthyroidism are consistent with a general increase in activity of the _____, commonly called a _____

Answer 35

sympathetic nervous system; thyroid storm

Question 36

in hypothyroid adults there may be exaggerated responses to ____ and ____ because there is an inadequate counteracting response from the SNS

Answer 36

narcotics; barbiturates