C27- Endocrine system 2

The thyroid gland is a butterfly-shaped endocrine gland located in the neck. It produces and secretes thyroid hormones, which are essential for regulating metabolism, growth, and development.

Thyroid hormones are essential for maintaining energy balance and regulating energy expenditure.

Thyroid hormones are produced by the thyroid gland in response to stimulation by thyroid-stimulating hormone (TSH).

TSH is regulated by thyrotropin-releasing hormone (TRH) produced by the hypothalamus.

Iodine is an essential nutrient for the synthesis of thyroid hormones.

Thyroid follicles are the functional units of the thyroid gland. They are spherical structures composed of follicular cells surrounding a central cavity filled with colloid.

Colloid is a protein-rich fluid that fills the thyroid follicles and contains thyroglobulin, the precursor to thyroid hormones.

Thyroglobulin (Tg) is a protein found in colloid. It's the precursor to thyroid hormones.

The apical surface of follicular cells faces the follicular lumen and is responsible for thyroid hormone synthesis.

The basolateral surface of follicular cells faces the interstitium and is responsible for releasing thyroid hormones into the bloodstream.

A complex formed by the proteins Megalin and Thyroglobulin, released into the blood after being transported across the follicular cell.

A process where a substance is enclosed in a vesicle and transported across a cell.

The breakdown of Thyroglobulin, releasing thyroid hormones (T3 and T4) into the blood.

An enzyme that removes iodine from monoiodotyrosine and diiodotyrosine, making it available for reuse.

The process where the thyroid gland regulates its own iodine uptake and metabolism.

Plasma proteins that bind to thyroid hormones, slowing their release into the tissues.

The active form of thyroid hormone, responsible for most of its effects.

A protein receptor that binds to T3 and triggers gene transcription.

A condition caused by insufficient thyroid hormone production or action.

A rare condition where tissues are less responsive to thyroid hormones.

A state where the body's cells are resistant to the effects of thyroid hormone, leading to high levels of free thyroid hormone in the blood and normal or elevated levels of TSH.

An autoimmune condition where the body produces antibodies that stimulate the TSH receptor, leading to excessive thyroid hormone production.

Enlargement of the thyroid gland, often associated with thyroid dysfunction.

Protruding eyes, a characteristic symptom of Graves disease.

A compensatory mechanism in thyroid-resistant state where the body tries to maintain normal thyroid function by increasing T3, T4, and TSH levels.

A type of hyperthyroidism where multiple nodules on the thyroid gland become overactive, leading to excessive thyroid hormone production.

An autoimmune response in which the body's immune system attacks the thyroid gland, leading to thyroid dysfunction.

A tumor in the pituitary gland that produces TSH, leading to hyperthyroidism.

Antibodies that mimic TSH and bind to the TSH receptor, leading to continuous stimulation and excess thyroid hormone production.

A process that ensures thyroid hormone production and release remain balanced. It involves communication between the hypothalamus, pituitary gland, and thyroid gland.

A tripeptide hormone synthesized in the hypothalamus and released by nerve terminals in the median eminence. It travels to the anterior pituitary via the portal capillary plexus.

A glycoprotein hormone synthesized and released by the anterior pituitary gland. It acts on the thyroid gland to stimulate thyroid hormone synthesis and release.

A protein located on the basolateral membrane of thyroid follicular epithelial cells. TSH binds to this receptor to initiate thyroid hormone production.

The process by which iodide ions (I-) are transported into the cytosol of the thyroid follicular cell. This process involves a sodium/iodide (Na+/I-) symporter, which moves two Na+ ions with each I- ion.

A protein involved in transporting and concentrating iodide in the thyroid epithelial cell. It uses the energy from the Na+ gradient to transport I- into the cell.

An enzyme that catalyzes the oxidation of iodide and its incorporation into tyrosine residues of thyroglobulin.

The process of combining iodide with thyroglobulin. It occurs in the colloid of thyroid follicles and is a crucial step in thyroid hormone synthesis.

A process where thyroglobulin bound to thyroid hormones is taken up by the thyroid cells and digested to release T3 (triiodothyronine) and T4 (thyroxine) into the bloodstream.