Chapter 25 - C. Thyroid and Parathyroid Glands

thyroid follicles

• thyroid gland is filled with microscopic sacs called ___

follicular cells

• thyroid follicles that are formed from a single layer of cuboidal cells called ___ whose shape can change from cuboidal to squamous or low columnar depending on thyroid gland activity.

thyroglobulin

• a thyroid hormone precursor, is synthesized by follicular cells and secreted into the lumen of the follicle where it is colloid.

colloid

• where thyroglobulin is stored

thyroid hormones (TH)

• thyroxine (T_⁴) or tetraiodothyronine

  • tetra = four

  • iodo = iodine

• triiodothyronine (T₃)

• both produced from thyroglobulin

tetraiodothyronine

• thyroxine (T_⁴)

parafollicular cells

• are located between the follicles, or C cells, which synthesize and secrete calcitonin

C cells

• parafollicular cells

calcitonin

• parafollicular cells or C cells synthesize and secrete ___

parathyroid glands

• embedded in the posterior surface of the thyroid gland are typically for small, round ___

• two types of of epithelial cells are found in ___:

  • chief cells

  • oxyphil cells

chief cells

• epithelial cells found in the parathyroid glands

• aka principal cells

• produces parathyroid hormone (PTH)

• more numerous and smaller

parathyroid hormone (PTH)

• chief cells produce ___

oxyphil cells

• epithelial cells found in the parathyroid glands

• function is unknown

TH

• thyroid hormones

T₄

• thyroxine

• tetraiodothyronine

  • tetra = four

  • iodo = iodine

T₃

• triiodothyronine

PTH

• parathyroid hormone