Thyroid and Parathyroid

Question 1

two cell types of the thyroid

Answer 1

1. follicular cells
2. Parafollicular cells, or C
   cells

Question 2

what type of hormones are thyroid hormones

Answer 2

monoamines but act like steroid

Question 3

thyroid hormones are derived from

Answer 3

tyrosine

Question 4

What causes thyroid hormones to act like steroids?

Answer 4

Iodine

Question 5

synthesized by follicular cells and stored in the colloid

Answer 5

thyroglobulin (this is the first step of thyroid hormone synthesis)

Question 6

a large glycoprotein containing many
tyrosine molecules

Answer 6

thyroglobulin

Question 7

active transport
of iodine from blood via sodium-iodide symport (NIS) pump (needed to go against the iodine gradient - more iodine in follicular cells than in blood)

Answer 7

Iodine Trapping (2nd step of thyroid hormone synthesis)

Question 8

iodine binds to thyroglobulin and gets
attached to tyrosine by thyroid peroxidase

Answer 8

Iodination of tyrosine (3rd step of thyroid hormone synthesis)

Question 9

T1 and T2 are coupled to make T3 and T4

Answer 9

coupling reaction (4th step of thyroid hormone synthesis)

Question 10

adds the iodine to tyrosine to make T3 and T4

Answer 10

thyroid peroxidase

Question 11

thyroglobulin is digested, freeing T3 and T4

Answer 11

lysosome digestion

Question 12

the biologically active thyroid hormone

Answer 12

T3

Question 13

the most secreted thyroid hormone

Answer 13

T4

Question 14

enzymes remove iodine to convert T4 to T3 
plays a major role in regulating intracellular T3 levels in a tissue-specific manner

Answer 14

deiodinase

Question 15

the primary trigger of thyroid hormone release

Answer 15

cold exposure

Question 16

The primary carrier protein for thyroid hormones

Answer 16

Thyroxine-binding globulin (TBG)

Question 17

How are steroid and thyroid hormone signaling different?

Answer 17

1. Thyroid hormones
   can’t diffuse across
   cell membranes
2. Receptors aren’t regulated by heat shock proteins (HSP); receptor is already bound to
   hormone response element (HRE)
3. Thyroid hormones
   form heterodimers

Question 18

decreased tolerance to cold is linked with

Answer 18

hypothyroidism

Question 19

excessive heat production and sweating are seen in

Answer 19

hyperthyroidism

Question 20

autoimmune disorder; your antibodies attack cells in thyroid (if
untreated leads to myxedema & coma)

Answer 20

Hashimoto’s disease

Question 21

immune disorder in which
your body makes an antibody
that mimics TSH

Answer 21

Graves disease

Question 22

was a common
cause of goiters (thyroid enlarges as it
tries to capture all the iodine it can)

Answer 22

Dietary iodine deficiency

Question 23

congenital (condition at birth), often due to low
maternal thyroid hormone or dietary deficiency

• impaired growth
• slow movement
• poor thermoregulation
• intellectual disabilities

Answer 23

Cretinism

Question 24

3 calciotropic hormones that regulate calcium balance

Answer 24

1. parathyroid hormone (PTH)- primary regulator. produced in parathyroid gland
2. Vitamin D- absorbs calcium from the intestines
3. Calcitonin- produced in thyroid gland

Question 25

principal cell type
arranged in clusters; produces hormone

Answer 25

chief cells

Question 26

Main hormone of the parathyroid

Answer 26

parathyroid hormone

Question 27

parathyroid hormone affect on calcium

Answer 27

Increases calcium concentration by acting on bone, kidney, and
intestine

• Increases osteoclast activity (release of calcium stored
  in bone)
• Decreases osteoblast activity

Question 28

cause formation of bone and stores calcium

Answer 28

osteoblasts

Question 29

resorb, or break down, bone and releases calcium

Answer 29

osteoclasts

Question 30

stimulates PTH secretion.

Answer 30

Low concentrations of calcium

Question 31

inhibits PTH secretion

Answer 31

High concentrations of calcium

Question 32

result of hypoparathyroidism

Answer 32

tetany and seizures

Question 33

result of hyperparathyroidism

Answer 33

kidney stones and osteoporosis

Question 34

Protects Against Excessive
Bone Resorption

Answer 34

calcitonin

Question 35

stimulates calcitonin secretion

Answer 35

High concentrations of calcium

Question 36

what does calcitonin do

Answer 36

1. acts to lower blood calcium
2. inhibits osteoclasts