How Well Do You Know Thyroid Hormone Synthesis?

The thyroid gland is located at the base of the neck and secretes thyroid hormones.

Thyroid Peroxidase (TPO) incorporates iodide into thyroglobulin, generating T3, T4, Mono-iodotyrosine, and Di-iodotyrosine (MIT, DIT).

Thyroglobulin is a glycoprotein containing tyrosine residues and is exported to the colloid where it is incorporated with iodide to generate thyroid hormones.

<p>Thyroid hormones have an important role in normal growth and development.</p> Signup and view all the answers

<p>Thyroid hormones enter cells through different amino acid transporters.</p> Signup and view all the answers

<p>Thyroid hormones stimulate basal metabolic rate (BMR) and gene expression, including the synthesis of polypeptides, hormones, and enzymes.</p> Signup and view all the answers

<p>What is the role of TSH in regulating thyroid hormone production? Answer: TSH stimulates synthesis and release of thyroglobulin and TPO in response to TRH from the hypothalamus.</p> Signup and view all the answers

<p>What happens to TRH and TSH release when there is a rise in the concentration of unbound T4 and T3 in the blood? Answer: TRH and TSH release are inhibited.</p> Signup and view all the answers

<p>Why is screening for thyroid disease in newborns critical? Answer: Congenital hypothyroidism disorders occur frequently, and hypothyroidism has an important role in diagnosis of primary hypothyroidism.</p> Signup and view all the answers

<p>Hyperthyroidism is a condition characterized by over-activity of the thyroid gland. Patients with hyperthyroidism typically have low TSH levels and increased free T3/T4 concentrations.</p> Signup and view all the answers

<p>Graves’ disease and toxic multi-nodular goitre are common causes of hyperthyroidism. Diagnosis is supported by eye signs, TSH receptor antibody, and increased isotope uptake upon thyroid scintiscan.</p> Signup and view all the answers

<p>Treatment options for hyperthyroidism include anti-thyroid therapy, beta-blockers, thyroid hormone replacement therapy, radioiodine therapy, or surgical intervention.</p> Signup and view all the answers

<p>The connection between cholesterol metabolism and thyroid hormone regulation is through Sterol Regulatory Element-binding Protein-2 (SREBP-2).</p> Signup and view all the answers

<p>Dyslipidemia is a condition characterized by abnormal lipid levels in the blood. Thyroid disorders can cause dyslipidemia, especially in patients with primary hypothyroidism.</p> Signup and view all the answers

<p>Primary hypothyroidism is more common than secondary hypothyroidism.</p> Signup and view all the answers

<p>TRH stimulates the pituitary gland to produce thyroid stimulating hormone (TSH).</p> Signup and view all the answers

<p>Hypothyroidism: fatigue, weight gain, and depression. Hyperthyroidism: weight loss, nervousness, and rapid heartbeat.</p> Signup and view all the answers

<p>Thyroid hormones are important for many functions in the body, including growth and development, metabolism, and the regulation of body temperature.</p> Signup and view all the answers

<p>What are the biochemical tests used to diagnose and monitor thyroid disease, and what are the additional tests that may be performed? Answer: The biochemical tests used to diagnose and monitor thyroid disease are measuring the levels of TSH and free T4 in the blood. Additional tests that may be performed are measuring the levels of antibodies to the thyroid gland or measuring the uptake of iodine by the thyroid gland.</p> Signup and view all the answers

<p>What is the relationship between thyroid hormones and cholesterol levels in the blood, and what are the mechanisms that lead to changes in cholesterol levels in patients with thyroid disease? Answer: People with hypothyroidism often have elevated levels of cholesterol in the blood, while people with hyperthyroidism may have decreased levels of cholesterol. The exact mechanisms that lead to these changes in cholesterol levels are still not fully understood, but it is thought that thyroid hormones may affect the metabolism of cholesterol in several ways. For example, thyroid hormones may increase the production of bile acids, which are important for the digestion of fats in the diet and the elimination of cholesterol from the body.</p> Signup and view all the answers

<p>What is the role of thyroid hormones in the regulation of cholesterol metabolism in the body, and how can this knowledge be applied to develop new treatments and therapies for patients with thyroid disease and related disorders? Answer: Thyroid hormones play an important role in the regulation of cholesterol metabolism in the body. By understanding the biochemistry of thyroid hormones and their effects on cholesterol, scientists and physicians can develop new treatments and therapies for patients with thyroid disease and related disorders.</p> Signup and view all the answers

<p>What is the role of thyroglobulin in thyroid hormone synthesis?</p> Signup and view all the answers

<p>Thyroglobulin acts as a precursor for thyroid hormones in thyrocytes.</p> Signup and view all the answers

<p>What are the two main thyroid hormones, and what are their functions?</p> Signup and view all the answers

<p>The two main thyroid hormones are thyroxine (T4) and triiodothyronine (T3), and they play crucial roles in metabolic regulation.</p> Signup and view all the answers

<p>What is the hypothalamus-pituitary-thyroid axis, and how does it regulate thyroid hormones?</p> Signup and view all the answers

<p>The hypothalamus-pituitary-thyroid axis regulates thyroxine and triiodothyronine secretion through positive and negative feedback mechanisms by using TRH and TSH from the hypothalamus and pituitary gland, respectively, to stimulate thyroid hormone synthesis and release.</p> Signup and view all the answers

<p>Negative feedback inhibition</p> Signup and view all the answers

<p>OATPs and LATS</p> Signup and view all the answers

<p>Thyroid hormones stimulate BMR by stimulating gene expression and T3 is produced by deiodination of T4</p> Signup and view all the answers

<p>1 in 4000 live births.</p> Signup and view all the answers

<p>Primary hypothyroidism is the failure of the thyroid gland itself while secondary hypothyroidism occurs due to the pituitary gland's failure to secrete TSH.</p> Signup and view all the answers

<p>Hashimoto's disease is an autoimmune form of hypothyroidism resulting in the destruction of the thyroid gland and the loss of hormone synthesis. Detection of autoantibodies is used to diagnose the condition.</p> Signup and view all the answers

<p>Graves' disease, toxic multinodular goiter, toxic nodule, chronic iodine excess, thyroiditis, and ectopic thyroid tissue.</p> Signup and view all the answers

<p>TSH receptor stimulating antibody, autonomous functions in areas of nodular gland, autonomously functioning nodule, high thyroidal iodine, and pituitary tissue secreting TSH, among others.</p> Signup and view all the answers

<p>Increased irritability, palpitations, weight loss, increased bowel frequency, tremor, tachycardia, and muscle weakness.</p> Signup and view all the answers

<p>What are the two anti-thyroid drugs used to treat Grave's disease, and how do they work?</p> Signup and view all the answers

<p>The two anti-thyroid drugs used to treat Grave's disease are propylthiouracil and methimazole. They work by inhibiting the production of thyroid hormones.</p> Signup and view all the answers

<p>What is the role of beta-blockers in treating Grave's disease, and what are some of their drawbacks?</p> Signup and view all the answers

<p>Beta-blockers can regulate tachycardia and tremor symptoms of Grave's disease, but they take time to work and have side effects.</p> Signup and view all the answers

<p>What are the two main options for treating thyroid hormone imbalances, and what are some of the benefits and drawbacks of each?</p> Signup and view all the answers

<p>The two main options for treating thyroid hormone imbalances are thyroid hormone replacement therapy and radioactive iodine therapy/surgery. Thyroid hormone replacement therapy requires monitoring and dosing and can be inconvenient, while radioactive iodine therapy/surgery can be more effective but have more significant side effects.</p> Signup and view all the answers