00:00 / 00:00
Age-related macular degeneration
Retinopathy of prematurity
Conductive hearing loss
Eustachian tube dysfunction
Tympanic membrane perforation
Acoustic neuroma (schwannoma)
Temporomandibular joint dysfunction
Gastroesophageal reflux disease (GERD)
Retropharyngeal and peritonsillar abscesses
Thyroglossal duct cyst
Eye conditions: Refractive errors, lens disorders and glaucoma: Pathology review
Eye conditions: Retinal disorders: Pathology review
Eye conditions: Inflammation, infections and trauma: Pathology review
Vertigo: Pathology review
Nasal, oral and pharyngeal diseases: Pathology review
Thyroid nodules and thyroid cancer: Pathology review
Parathyroid disorders and calcium imbalance: Pathology review
0 / 11 complete
0 / 7 complete
amyloidosis in p. 216
associations p. 729
carcinogens in p. 223
goiter p. 348
metastases to p. 224
Psammoma bodies in p. 225
Sam Gillespie, BSc
Tanner Marshall, MS
Pauline Rowsome, BSc (Hons)
The thyroid gland is an endocrine gland in the neck that produces thyroid hormones.
If the cells of the thyroid gland start to divide uncontrollably, then that’s considered a thyroid cancer.
Normally, the hypothalamus, which is located at the base of the brain, secretes thyrotropin-releasing hormone, or ΤRH, into the hypophyseal portal system - which is a network of capillaries linking the hypothalamus to the anterior pituitary.
The anterior pituitary then releases a hormone of its own, called thyroid-stimulating hormone, thyrotropin or simply TSH.
TSH stimulates the thyroid gland which is a gland located in the neck that looks like two thumbs hooked together in the shape of a “V”.
The entire gland is covered in a thin, tough membrane called the fibrous capsule.
If we zoom into the thyroid gland, we’ll find thousands of follicles, which are small hollow spheres whose walls are lined with follicular cells, and are separated by a small amount of connective tissue.
Follicular cells convert thyroglobulin, a protein found in follicles, into two iodine-containing hormones, triiodothyronine or T3, and thyroxine or T4.
Once released from the thyroid gland, these hormones enter the blood and bind to circulating plasma proteins.
Only a small amount of T3 and T4 will travel unbound in the blood, and these two hormones get picked up by nearly every cell in the body.
Once inside the cell T4 is mostly converted into T3, and it can exert its effect. T3 speeds up the basal metabolic rate.
So as an example, they might produce more proteins and burn up more energy in the form of sugars and fats. It’s as if the cells are in a bit of frenzy.
T3 increases cardiac output, stimulates bone resorption - thinning out the bones, and activates the sympathetic nervous system, the part of the nervous system responsible for our ‘fight-or-flight’ response.
Thyroid cancer is a type of cancer that develops in the cells of the thyroid gland, specifically from follicular cells or C cells. There are three main types of thyroid cancer: differentiated, medullary, and anaplastic.
In differentiated thyroid cancer, the cancer arises from follicular cells, and it's known as differentiated because the cancer cells look and act like normal thyroid cells. Medullary carcinoma arise from the C-cells of the thyroid which produce calcitonin, whereas anaplastic carcinomas are named so because they have altered cells that don't look anything like normal thyroid cells. Symptoms of thyroid cancer can include a lump or swelling in the neck, pain in the neck or throat, difficulty swallowing or breathing, hoarseness, and a persistent cough. The treatment of thyroid cancer depends mostly on the type of cancer and how it has spread. Options
Copyright © 2023 Elsevier, except certain content provided by third parties
Cookies are used by this site.
USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME). COMLEX-USA® is a registered trademark of The National Board of Osteopathic Medical Examiners, Inc. NCLEX-RN® is a registered trademark of the National Council of State Boards of Nursing, Inc. Test names and other trademarks are the property of the respective trademark holders. None of the trademark holders are endorsed by nor affiliated with Osmosis or this website.