thyroid hormone
Quick Summary
Thyroid hormones, thyroxine (T4) and triiodothyronine (T3), are produced by the thyroid gland in the neck. Their synthesis involves adding iodine to the amino acid tyrosine, which is part of a protein called thyroglobulin.123
These hormones are crucial for regulating the body's metabolism and growth, influencing oxygen consumption and heat production in cells. Thyroxine acts as a precursor, largely converted to the more active triiodothyronine in tissues. The production of thyroid hormones is controlled by hormones from the pituitary and hypothalamus in a negative feedback loop. Imbalances in thyroid hormone levels can lead to conditions like hyperthyroidism (excess production) or hypothyroidism (deficient production).2314
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- thyroid function test
…production of the two active thyroid hormones, thyroxine (T4) and triiodothyronine (T3), by the thyroid gland and the production of thyrotropin (thyroid-stimulating hormone, TSH), the hormone that regulates thyroid secretion, by the pituitary gland. The best and most widely used tests are measurements of serum thyrotropin and thyroxine. The secretion…
Read More…production of the two active thyroid hormones, thyroxine (T4) and triiodothyronine (T3), by the thyroid gland and the production of thyrotropin (thyroid-stimulating hormone, TSH), the hormone that regulates thyroid secretion, by the pituitary gland. The best and most widely used tests are measurements of serum thyrotropin and thyroxine. The secretion…
Read More - protein-bound iodine test
Thyroid hormones are formed by the addition of iodine to the amino acid tyrosine and are normally transported in the bloodstream by carrier proteins. In the PBI test, these carrier proteins are precipitated from the blood, and the quantity of bound iodine is measured. Under certain…
Read MoreThyroid hormones are formed by the addition of iodine to the amino acid tyrosine and are normally transported in the bloodstream by carrier proteins. In the PBI test, these carrier proteins are precipitated from the blood, and the quantity of bound iodine is measured. Under certain…
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thyroid glandAnatomy of the thyroid gland…the enzymes needed to release thyroid hormone from thyroglobulin. When thyroid hormones are needed, thyroglobulin is reabsorbed from the colloid in the follicular lumen into the cells, where it is split into its component parts, including the two thyroid hormones thyroxine (T4) and triiodothyronine (T3). The hormones are then released,…
Read More…the enzymes needed to release thyroid hormone from thyroglobulin. When thyroid hormones are needed, thyroglobulin is reabsorbed from the colloid in the follicular lumen into the cells, where it is split into its component parts, including the two thyroid hormones thyroxine (T4) and triiodothyronine (T3). The hormones are then released,…
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hormoneThyrotropin (thyroid-stimulating hormone)Thyrotropin (also called thyroid-stimulating hormone, or TSH) regulates the thyroid gland through a feedback relationship similar to that for ACTH; thyrotropin increases the secretion of the hormones from the thyroid gland and, if its action is prolonged, evokes increases in cell number (hyperplasia)…
Read MoreThyrotropin (also called thyroid-stimulating hormone, or TSH) regulates the thyroid gland through a feedback relationship similar to that for ACTH; thyrotropin increases the secretion of the hormones from the thyroid gland and, if its action is prolonged, evokes increases in cell number (hyperplasia)…
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- dwarfism
Inadequate production of thyroid hormone during gestation and early infancy results in a condition known as cretinism, which is characterized by growth retardation and severe mental retardation. Several of the mucopolysaccharidoses (disorders of mucopolysaccharide metabolism) are characterized by dwarfism, often with mental retardation. Some infants having hereditary forms…
Read MoreInadequate production of thyroid hormone during gestation and early infancy results in a condition known as cretinism, which is characterized by growth retardation and severe mental retardation. Several of the mucopolysaccharidoses (disorders of mucopolysaccharide metabolism) are characterized by dwarfism, often with mental retardation. Some infants having hereditary forms…
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goitre…steps in the synthesis of thyroid hormone. Like iodine deficiency, these defects result in increased thyrotropin secretion. More-common causes are one or multiple nodules in the thyroid (uninodular or multinodular goitre), infiltration of the thyroid by lymphocytes or other inflammatory cells (thyroiditis), or stimulation of thyroid growth (and function) by…
Read More…steps in the synthesis of thyroid hormone. Like iodine deficiency, these defects result in increased thyrotropin secretion. More-common causes are one or multiple nodules in the thyroid (uninodular or multinodular goitre), infiltration of the thyroid by lymphocytes or other inflammatory cells (thyroiditis), or stimulation of thyroid growth (and function) by…
Read More- hyperthyroidism
thyroid hormone by the thyroid gland. Most patients with hyperthyroidism have an enlarged thyroid gland (goitre), but the characteristics of the enlargement vary. Examples of thyroid disorders that give rise to hyperthyroidism include diffuse goitre (Graves disease), toxic multinodular goitre (
Read Morethyroid hormone by the thyroid gland. Most patients with hyperthyroidism have an enlarged thyroid gland (goitre), but the characteristics of the enlargement vary. Examples of thyroid disorders that give rise to hyperthyroidism include diffuse goitre (Graves disease), toxic multinodular goitre (
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