Thyroid

Question 1

define Hashimoto disease

Answer 1

• common cause of hypothyrodism due to autoimmune antibodies directed against thyroglobulin or thyroid peroxidase
• results in low TH productiong (and high circulating TSH) and eventual destruction of thyroid gland

Question 2

define graves disease

Answer 2

• autoantibodies bind to and stimulate TSH receptors leading to production of EXCESSIVE amounts of thyroid hormones

Question 3

what is the function of thyroid hormones

Answer 3

• maintain energy homeostasis and regulate energy expenditure
• stimulates carb and fat metabolism
• Thyroid hormone receptors are found virtually in all tissues and located on the nuclei of target cells

Question 4

what occurs if you have a deficiency of thyroid hormones?

Answer 4

• failure of body growth and mental retardation

- cretinism = extreme hypothyroidism in early life

Question 5

what does the measure of TSH mean?

Answer 5

• Low TSH could indicate inadequate hypothalamus activity or too much thyroid activity

Question 6

describe thyroid hormone transport

Answer 6

• thyroid hormones are bound to plasma proteins (THYROXINE-BINDING GLOBULIN or TRANSTHRYRETIN)
• Albumin and lipoproteins also bind and transport thyroid hormones
• free from thyroid hormoens is responsible for neg feedback on pituitary/hypothalamus

Question 7

define iodide trapping

Answer 7

• after iodide is transported into thyroid epithelial cell, it is concentrated and this is called trapping

Question 8

define organification

Answer 8

• process of bindign iodine with thyroglobulin

Question 9

Define Thyroxine-binding prealbumin

Answer 9

specific thyroid binding protein transthyretin

- binds to retinol

Question 10

thyroglobulin

Answer 10

storage form of T3/T4

Question 11

thryotropin

Answer 11

TSH = controls synthesis and secretion of thyroid hormones

Question 12

thyrotropin-releasing hormone (TRH)

Answer 12

• from hypothalamus, causes TSH release from ant. pit

Question 13

define goiter

Answer 13

• swelling of the thyroid gland
• due to prolonged increases in TSH stimulation of thyroid cause it to enlarge
• also can be caused by deficiency in iodide
• also possibly due to hypothyrodism??

Question 14

What values do you expect to see in Primary hypothyroidism

Answer 14

• Low T4
• High TRH
• High TSH

Question 15

What values do you expect to see in pituitary hypothyroidism (secondary)

Answer 15

• Low T4
• High TRH
• Low TSH

Question 16

What values do you expect to see in hypothalamic hypothyroidism

Answer 16

• Low T4
• Low TRH
• Low TSH

Question 17

What values do you expect to see in Pituitary hyperthyroidism

Answer 17

• High T4
• Low TRH
• High TSH

Question 18

What values do you expect to see in graves disease

Answer 18

• High T4
• Low TRH
• Low TSH