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Thyroid gland

Glandula thyroidea

Butterfly-shaped and highly vascular, the thyroid gland lies in the anterior neck, its two lateral lobes joined by an isthmus that crosses the trachea at the level of the second and third tracheal cartilages. It produces the thyroid hormones T3 and T4, which set the metabolic rate, drive protein synthesis, and adjust sensitivity to other hormones, and it secretes calcitonin, which contributes to calcium homeostasis. Blood reaches it through the superior and inferior thyroid arteries. Hashimoto's thyroiditis underlies much hypothyroidism and Graves' disease much hyperthyroidism, while nodules and goiter affect large numbers of people. Thyroid cancer is relatively uncommon and carries an excellent prognosis when treated early, though thyroidectomy risks injury to the recurrent laryngeal nerve.

A butterfly-shaped gland in the anterior neck, consisting of two lateral lobes connected by an isthmus across the trachea at the level of the 2nd-3rd tracheal cartilages. It is highly vascularized, receiving blood from the superior and inferior thyroid arteries.

On this page
種類 Gland
器官系 Endocrine
身体部位 Neck
親構造 endocrine gland
ラテン語名 Glandula thyroidea
FMA ID 9603

機能

Produces thyroid hormones (T3 and T4) that regulate metabolic rate, protein synthesis, and sensitivity to other hormones. Also produces calcitonin, which helps regulate calcium homeostasis.

臨床的意義

Hypothyroidism (Hashimoto's thyroiditis) and hyperthyroidism (Graves' disease) are common endocrine disorders. Thyroid nodules and goiter affect millions. Thyroid cancer, while relatively uncommon, has excellent prognosis when treated early. Thyroidectomy risks recurrent laryngeal nerve injury.

Frequently Asked Questions

What hormones does the thyroid gland produce?

The thyroid gland produces three hormones: thyroxine (T4) and triiodothyronine (T3), which regulate metabolism, growth, and development throughout the body, and calcitonin, produced by parafollicular C cells, which lowers blood calcium levels. T4 is the major secretory product but T3 is the biologically more active form, converted from T4 in peripheral tissues.

Where is the thyroid gland located?

The thyroid gland is located in the anterior neck, lying just inferior to the thyroid cartilage (Adam's apple) at the level of vertebrae C5–T1. It consists of two lobes connected by a central isthmus, giving it a butterfly or H-shaped appearance. It is highly vascular and wraps around the trachea anteriorly and laterally.

What is the difference between hypothyroidism and hyperthyroidism?

Hypothyroidism occurs when the thyroid produces insufficient hormones, causing fatigue, weight gain, cold intolerance, constipation, and bradycardia. Hashimoto's thyroiditis is the most common cause. Hyperthyroidism results from excess hormone production, causing weight loss, heat intolerance, palpitations, anxiety, and exophthalmos. Graves' disease is the most common cause of hyperthyroidism, driven by autoimmune stimulation of TSH receptors.

References

  1. Foundational Model of Anatomy — FMA:9603 Reference anatomy ontology (University of Washington)
  2. UBERON — UBERON:0002046 Cross-species anatomy ontology (EMBL-EBI Ontology Lookup Service)
  3. Wikipedia — Thyroid gland Encyclopedia article (verified cross-reference)

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Educational Disclaimer

This content is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical decisions.

Data sources: Terminologia Anatomica, Foundational Model of Anatomy, Wikidata.