Thyroid Gland Flashcards

Flashcards about the thyroid gland, its hormones, and related clinical disorders.

What are the major arteries that supply blood to the thyroid gland?

Superior thyroidal artery and Inferior thyroid artery

Which nerve is associated with the thyroid gland?

Laryngeal nerve

What is the main component of the colloid found in thyroid follicles?

Thyroglobulin

What are the main functions of follicular cells in the thyroid gland?

Collect and transport iodine, synthesize and secrete thyroglobulin, remove thyroid hormones from thyroglobulin, and secrete thyroid hormone into the circulation.

What hormone do parafollicular cells (C cells) secrete?

Calcitonin

What are the precursors of thyroid hormone?

Iodine and Tyrosine

What are the four main processes of thyroid hormone synthesis?

Iodide trapping, oxidation of iodide ions, iodination of tyrosine molecules, and coupling reaction

What is the function of the oxidation of iodide ions in thyroid hormone synthesis?

Conversion of iodide ions to an oxidized form (iodine).

What enhances iodination of tyrosine molecules?

TSH and TPO

What hormones are created during the coupling reaction of thyroid hormone synthesis?

Triiodothyronine (T3) and Thyroxine (T4)

What process is responsible for thyroid secretion?

Endocytosis

Which thyroid hormone is most abundant?

Tetraiodothyronine (T4)

Which thyroid hormone is most biologically active?

Triiodothyronine (T3)

What are the three types of thyroid-specific deiodinases?

Type I deiodinase, Type II deiodinase, and Type III deiodinase

How is thyroid hormone secretion regulated?

Negative feedback

What is the most common cause of primary hyperthyroidism?

Graves' disease

What are the typical hormone levels in primary hyperthyroidism?

Increased T3 and T4, decreased TSH and TRH

What are the most common symptoms of hyperthyroidism?

Tremors and Palpitations

What are common treatments for hyperthyroidism?

Surgical removal, pharmacologic treatment, and high concentrations of iodides.

What are the typical hormone levels in primary hypothyroidism?

Decreased T3 and T4, increased TSH and TRH