Thyroid gland

Glandula thyroidea

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.

Type Gland
Body System Endocrine
Body Region Neck
Parent Structure endocrine gland
Latin Name Glandula thyroidea
FMA ID 9603

Function

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.

Clinical Significance

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.

Related Structures

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Educational Disclaimer

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