Endocrinology Flashcards
What is endocrinology?
A collection of glands that produce hormones that regulate metabolism, growth and development, tissue function, sexual function, reproduction, sleep, and mood, among other things.
Where is the thalamus located?
Anterior neck C5-T1
What muscles does the thalamus lie behind?
sternohyoid and sternothyroid
What do the thalamus lie inferiorly to?
the thyroid cartilage of the larynx
Which arteries supply the thyroid?
superior and inferior thyroid arteries
Where does the superior thyroid artery arise from?
the first branch of the external carotid artery
Which portions of the gland does the superior thyroid artery supply?
the superior and anterior portions
Where does the inferior artery arise from?
thyrocervical trunk, a branch of the subclavian artery
What portion of the thalamus does the inferior artery supply?
postern-inferior aspect
What innervates the thalamus?
branches from the sympathetic trunk
What controls hormone release from the thalamus?
the pituitary gland
At 3-4 weeks what do the thyroid glands appear as?
an epithelial proliferation at the base of the pharynx
What happens to the epithelial proliferation at the base of the pharynx?
It migrates down the thyroglossal duct to below the larynx
At what week do the glands produce thyroxine?
18-20 weeks
Which 3 structures are seen in thyroid histology?
- follicles
- follicular cells
- parafollicular/C cells
What do follicles contain?
thyroglobulin in which iodine is stored and taken up from the blood
What is the epithelium of follicular cells?
Simple cuboidal BUT becomes columnar with increased metabolic activity
How are follicular cells arranged?
In hollow circles called follicles
What hormones do the follicles produce?
T3 and T4
What do parafollicular/C cells produce?
calcitonin for Ca2+ homeostasis
What is the endocrine system made up of?
The endocrine system is made up of the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pancreas, ovaries (in females) and testicles (in males)
What does endocrinology mean in Greek?
“endo,” meaning within, and “crinis,” meaning to secrete
How does endocrinology work?
a gland selects and removes materials from the blood, processes them and secretes the finished chemical product for use somewhere in the body.
What two hormones does the thyroid gland produce?
Thyroxine T4 (contains 4 iodines) Triiodothyronine T3 (contains 3 iodines)
Which is the major thyroid hormone?
T3 because T4 is converted to T3 by enzymes known as doiodinases in target cells
The concentration of which thyroid hormone is higher in the blood?
T4 (T4 = reservoir for T3)
What is thyroxin made from?
tyrosine and iodine
