Class notes
THE THYROID GLAND
Physiology of the thyroid gland
[Show more]
Seller
Follow
Content preview
ENDOCRINOLOGY
THE THYROID GLAND
, THYROID GLAND
Functional Anatomy
• Thyroid gland is located in the neck, anterior to the trachea.
• It weighs about 32 grams and it consists of two lateral lobes connected
by a narrow isthmus.
• The lobes are divided into lobules by the connective tissue capsule
covering it.
• Each lobule is then subdivided into between 20 and 40 roughly spherical
follicles that vary in size between 0.02 and 0.9 mm in diameter.
• Lying between and separating the follicles is a connective tissue stroma
containing a rich network of capillaries, lymphatics and nerves.
• The follicular cells are filled with a secretory substance called colloid
substance.
• The major constituent of the colloid substance is a large glycoprotein
called thyroglobulin.
• The appearance of the follicular cells varies with the activity of the
thyroid gland.
• Scattered between the epithelial cells are a number of cells with clear
cytoplasm which do not penetrate as far as the colloid which are called
the parafollicular cells or C- cells.
, • Blood and Nerve supplies
• Thyroid gland derives its blood supply from branches of the
Superior and inferior thyroid arteries, which ramify to form an
extensive capillary network in the gland.
• These capillaries then anastomose to form venous plexuses.
• From these venous plexuses arise the superior, middle and inferior
thyroid veins.
• Both the superior and middle thyroid veins drain into the internal
jugular vein while the inferior thyroid vein drains into the
innorminate (brachiocephalic) vein.
• Nerves fibers to the thyroid gland are along the blood vessels.
• These nerves are Postganglionic symphathetic fibers and
preganglionic parasymphathetic fibers.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller DaniBrezy54. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for CA$13.94. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
73091 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now