Thyroid Flashcards
TRH from the hypothalamus stimulates ___ secretion from the anterior pituitary gland
(control of thyroid hormone secretion)
TSH
Thyroid hormone synthesis/secretion occurs within the thyroid gland in the presence of __
(control of thyroid hormone secretion)
TSH
Negative feedback causes the hypothalamus to stop or slow production of TRH which then causes the ___ pituitary to stop or slow release of TSH
anterior
thyroid hormones, think:
T3, T4
Anything that increases cellular energy demand causes an increase in __ production (e.g., Cold environment, hypoglycemia, high altitude, pregnancy
)
T3/T4
Lateral lobes (wings) on each side of the trachea projecting upward to just below the ___
Lobes connected by an ___ located anterior to the trachea
(thyroid location)
larynx
isthmus
Largest of pure endocrine glands
Thyroid gland
A thyroid has an ___ blood supply
extensive
fer all them hormones
___ are the functional units of the thyroid
Follicles
A follicle is a sphere with its wall consisting of __ cells
follicular
This inside of this unit is called the __
thyroid micro
colloid
___ cells reside in between follicles
Parafollicular
produce calcitonin but not considered a thyroid hormone
The inactive form of thyroid hormone
Much more abundant, but less potent
Tetraiodothyronine (Thyroxine, T4)
The active form of thyroid hormone
Much more potent, less abundant
Triiodothyronine (T3)
Made in small quantities by parafollicular cells, helps to regulate calcium levels of the blood
(not a “thyroid hormone” only made in the thyroid)
Calcitonin
Follicular cells pull ___ ions from the blood stream
iodide
Follicular cells are also producing ____
thyroglobulin (TGB) (glycoprotein-carbon chain of many amino acids)
produced in endoplasmic reticulum
Packaged in the Golgi apparatus
Released by exocytosis into the lumen (colloid)
thyroglobulin (TGB)
glycoprotein-carbon chain of many amino acids – tyrosine
Iodide requires ___ to make iodine (the useable form for thyroid hormone synthesis)
____ oxidizes the iodide into iodine (I2)
oxidation
Perioxidase
(Insuffienct ___ lead to thyroid issues)
tyrosine, iodine, or peroxidase
(T3 and T4 are __ soluble)
lipid
At this point there is now TGB and iodine (I2) roaming in the colloid
Simultaneously TGB and ___ begin to react with each other forming bonds (at the tyrosine portions of TGB)
“middle step”
iodine
One iodine to one tyrosine
monoiodotyrosine (MIT)
Two iodines to one tyrosine
diiodotyrosine (DIT)