Thyroid Flashcards
What’s is the tissue derivative the thyroid develops from
Endodermal derivative
What are the functional units of the thyroid
Secretory follicles
The pyramidal lobe is a remnant of what
The thyroglossal duct
What cells are responsible for the production of t3 and t4
Follicular cells
What type of epithelium forms thyroid follicles
Simple cuboidal or low columnar
What are the principle cells of thyroid follicles
Follicular cells
What regulates t3 and t4 secretion from follicular cells
Tsh from anterior pituitary
What is t4
Thyroxine
What is t3
Triiodothyronine
What are t3 and t4 responsible for
Cell and tissue basal metabolism
Heat production
Body growth and development
What is the major component of colloid
Thyroglobulin
What is thyroglobulin
Inactive form of thyroid hormones
What is unique about the storage capacity about the thyroid gland
It stores most of its hormones extracellularly
True or false: t3 and t4 cross the placenta
True
What are the results of insufficient amounts of thyroid hormone during pregnancy
CNS damage Defective myelination Reduced neurons Mental retardation STUNTED BODY GROWTH
What do parafollicular cells secrete
Calcitonin
What other gland besides the para follicular cells also secretes calcitonin
Thyroid gland
What is the antagonist to parathyroid hormone
Calcitonin
What is the effect of calcitonin
Inhibits osteoclasts (destroy bone) Increases calcium deposition
If you have increased blood calcium, your calcitonin levels….
Increase
If you have decreased blood calcium, your calcitonin levels…
Decrease
What do the parathyroid glands develop from?
3rd and 4th pharyngeal pouches
What is derived from the third pharyngeal pouch?
Inferior parathyroid glands
Thymus
What is derived from the 4th pharyngeal pouch
Superior parathyroid glands
What cells are responsible for regulating fetal calcium metabolism
Chief cells
What cells are responsible for the secretion of PTH
Chief cells (principal cells)
What cells in the parathyroid gland develop later, are less numerous, and are not known to have a function
Oxyphil cells
What does the parathyroid gland secrete
Parathyroid hormone
What does PTH regulate
Calcium and phosphate levels
How does PTH work on bone
Activates osteoclasts
Calcium and phosphate are released
How does PTH work on the kidney
Tubular reabsorption of calcium is increased
Urinary excretion of phosphate is increased
Vitamin d3 is hormonally activated
How does PTH work on intestines
Calcium absorption is increased
