Thyroid gland

Question 1

How are hormones stored in the thyroid gland and how are they secreted?

Answer 1

Hormones are stored in the cavities in the gland that are surrounded by secretory cells (follicular cells) to form a follicle. To secrete this hormone it is re-absorbed from the cavities into the secretory cells and then released into interstitial spaces.

Question 2

Tri-iodo thyronine (T3) hormone and thyroxine (T4) is secreted by the thyroid gland, what are its roles? True or false: these hormones are regulated by TSH.

Answer 2

• T3 is the more active hormone.
• Regulates basal metabolic rate (amount of energy per unit time that a person needs to keep the body functioning at rest.)
• TRUE

Question 3

What is colloid?

Answer 3

• The chemical in the cavity that will eventually produce T3 and T4.
• Made up of glycoprotein called thyroglobulin.

Question 4

What is the role of clear cells (parafollicular cells)?

Answer 4

Secretes calcitonin which regulates calcium levels by decreasing it when too high. They also have a pale cytoplasm.

Question 5

2 different names for follicular cells?

Answer 5

Thyrocytes or thyroid epithelial cells