Endocrine - Thyroid and Parathyroid

Question 1

What are the two lateral lobes of the thyroid connected by?

Answer 1

Narrow isthmus

Question 2

Is the thyroid surrounded by a capsule?

Answer 2

Yes

Question 3

What is the main structural unit of the thyroid?

Answer 3

Thyroid follicle

Question 4

What cell type compose the thyroid follicles?

Answer 4

Cuboidal follicular epithelium

Question 5

What is contained in the cyst-like central cavity of thyroid follicles?

Answer 5

Colloid

Question 6

What surface of the cells are in contact with the colloid?

Answer 6

Apical

Question 7

What surrounds the basal lamina of the thyroid follicles?

Answer 7

Dense network of fenestrated capillaries

Question 8

What are the two types of cells of the follicular epithelium?

Answer 8

Follicular cells

Parafollicular cells

Question 9

What are the principal endocrine cells of the thyroid gland? What do they originate fom?

Answer 9

Follicular cells

Endodermal origin

Question 10

More activate follicles have _____ epithelium

Answer 10

Taller

Question 11

What are the two main hormones synthesized by follicular cells?

Answer 11

Thryoxine 3 and 4 (T3 and T4)

Question 12

What regulates secreting of T3 and T4?

Answer 12

TSH from pituitary gland

Question 13

What two main things do T3 and T4 regulate in the body?

Answer 13

Metabolism

Heat production

Question 14

What is synthesized in the RER and Golgi of follicular cells? Where is it secreted?

Answer 14

Thyroglobulin

Secreted into lumen of follicle

Question 15

How is iodide transported into the follicular lumen? Where is it oxidized to iodine?

Answer 15

Actively transported

Apical membrane

Question 16

Iodination of thyroglobulin forms what two hormones?

Answer 16

T3 and T4

Question 17

What is the main function of parafollicular cells?

Answer 17

Synthesis of calcitonin

Question 18

What does calcitonin do?

Answer 18

Lower blood Ca by suppressing osteoclast activity

Question 19

What are parafollicular cells dervied from?

Answer 19

Neural crest cells

Question 20

Where are parathyroid glands found? How many pairs?

Answer 20

Embedded within the thyroid

Two pairs - superior and inferior

Question 21

What are the two types of cells of the parathyroid gland?

Answer 21

Parathyroid chief cell

Oxyphil cell

Question 22

What do parathyroid chief cells produce?

Answer 22

Parathyroid hormone - PTH

Question 23

What does PTH do?

Answer 23

Antagonize calcitonin

Question 24

What is the most distinctive feature of oxyphil cells? what do they stain intensely with?

Answer 24

Large number of mitochondria

Stain intensely with acidic dyes