Thyroid Anatomy, Physiology and Embryology of the Thyroid Gland.

Follicular cells produce the __ and __ hormone. The production of the hormones (i.e. the colloid) rely on _______.

Follicular cells produce the T4 and T3 hormone. The production of the hormones (i.e. the colloid) rely on iodine.

What two organs regulate hormone secretion of the thyroid?

Hypothalamus and Pituitary Gland.

Where does the inferior thyroid vein drain into?

Inferior thyroid vein (one on either side) drains the inferior portion of the thyroid gland into the brachiocephalic vein, which then in turn drains into the Superior vena cava.

What is the major function of the thyroid?

Major function is to secret thyroid hormones that regulate body metabolism (T3/T4) and calcium homeostasis (calcitonin)

Where does the middle thyroid vein drain into?

Middle thyroid vein drains the inferior/middle portion of the thyroid gland into the internal jugular vein.

Primary function of T3/T4?

Regulate metabolism

What causes a pyramidal lobe of the thyroid?

Result of a 'persistent remnant' of the thyroglossal duct.

Where does the superior thyroid vein (STV) drain into?

STV drains into the superior portion of the thyroid gland into the internal jugular vein.

Superior thyroid artery (one on either side) is a branch of the _______ ____ _______. This superior thyroid artery then runs downward to supply the superior portion of the thyroid gland.

Superior thyroid artery (one on either side) is a branch of the external carotid artery. This superior thyroid artery then runs downward to supply the superior portion of the thyroid gland.

Describe the venous drainage of the thyroid gland.

Consists of paired superior, middle and inferior thyroid veins.

The inferior thyroid artery is a branch of the __________ _______ which arises from the ______ ______. It runs downward to supply the _______ portion of the thyroid gland.

The Inferior thyroid artery (one on either side) is a branch of the thyrocervical trunk which is a branch that arises from the subclavian artery. This inferior thyroid artery then ascends to supply the inferior portion of the thyroid gland.

Pituitary gland secretes what?

Thyroid stimulating hormone

The nerve supply of the thyroid is derived from the - ? These nerves provide - ?

The nerve supply to the thyroid gland is derived from the superior, middle and inferior cervical sympathetic ganglion. These nerves provide autonomic innervation to the thyroid gland and its vasculature.

Normal anatomical variant of the thyroid?

The pyramidal lobe of thyroid (also known as Lalouette pyramid) is a normal anatomical variant of the thyroid gland.

What is the name of the variant of thyroid blood supply? Where does it branch from?

Thyroid ima artery Most commonly a branch of the brachiocephalic trunk and ascends on the anterior surface of the trachea to supply both the trachea and the isthmus of the thyroid gland.

Hypothalamus secretes what?

Thyroid releasing hormone

Primary function of calcitonin?

• Calcitonin: Primary function is to decrease the blood calcium levels (preventing hypercalcemia)

Describe the arterial supply of the thyroid

• Consists of paired superior and inferior thyroid arteries and occasionally an uncommon variant (which can arise from different locations) called thyroid ima artery.

What kind of organ is the Thyroid? What 3 main hormones does it produce? What do these hormones affect?

• ENDOCRINE organ (ductless gland) • It produces 3 MAIN hormones: • T4 - Thyroxine • T3 - Triiodothyronine • Calcitonin These hormones affect body metabolism, growth and development.