The Thyroid Gland Trivia Quiz

Answer: Thyroid cartilage

The thyroid gland is actually named for its position on the thyroid cartilage, which forms the Adam's Apple (also called the laryngeal prominence). The thyroid cartilage in turn gets its name for the Greek for "shield" referring to its shape. The thyroid gland is not shield-shaped at all; it tends to be thought of as butterfly-shaped and wrapping around the cartilage, however when the neck is opened to view the gland, it is rather amorphous.

The arytenoid and cricoid cartilages are indeed situated in the larynx, but the costal cartilages are not: they are the small areas of cartilage that join the bony ribs to the sternum.

Answer: Levator glandulae thyroideae

The shape of the thyroid gland can generally be thought of as a butterfly shape, or two teardrops linked by a bridge, the isthmus. Each "teardrop" is a lobe, each of which has an apex and a base. These structures are present in the normal thyroid gland, although the isthmus can be absent.

There can be a pyramidal lobe just above the isthmus, which is seen relatively often. The levator glandulae thyroideae (or: levator of the thyroid gland) is not a muscle, despite what its name suggests. It is in fact the fibrous remnants of the thyroglossal duct, which appears in embryonic development of the thyroid gland.

Answer: Tongue

I accept "tongue" although technically there is no tongue in the embryo at the time the thyroid gland develops - the gland develops in the pharynx from the foramen caecum, which is a shallow pit seen near the back of the adult tongue. From this foramen, the gland descends into the neck via the thyroglossal duct.

This descent can go wrong in various ways - if the thyroid gland does not descend, it develops at the back of the tongue in the adult, giving a lingual thyroid. It can also descend too far into the chest, giving a mediastinal thyroid.

Answer: Tyrosine

Inside the follicles, the thyroid hormones and thyrogloublin together form a solid precipitate called colloid. The thyroid hormones are derived from the amino acid tyrosine and iodide ions - tyrosine is a non-essential amino acid, which means it is not required in the diet, as the body can synthesize it. However, it is important to keep your iodine levels at suitable levels to avoid a lack of thyroid hormones.

The thyroid hormones are T3 (or triiodothyronine) and T4 (or tetraiodothyronine, usually called thyroxine). T3 is more potent than thyroxine, so the latter is usually converted to T3 in the body.

Answer: Calcitonin

Parafollicular cells are also called C cells, which reflects their release of the hormone calcitonin. The cells are located around the follicles in the thyroid tissue. They collaborate with parathyroid glands to move calcium ions around the body. The parathyroid glands are pea-sized glands that are situated at the back of the thyroid gland; they release parathyroid hormone. Parathyroid hormone acts to increase the levels of calcium in the blood by removing it from the gut and bone. Calcitonin keeps the balance by moving calcium back into bone from the blood.

It is vital that the balance is kept, because too much calcium can cause tetany (prolonged muscle contraction) which can be life-threatening.

Answer: Decrease temperature

The thyroid hormones work to increase the basal metabolism of the body, and tend to increase many of the body's functions, such as those mentioned in the alternative answers, plus increasing oxygen consumption and activating glycolysis (which is part of the respiration process, where energy is produced). Of course this means that an imbalance of thyroid hormones can have drastic effects, causing disease.

Answer: The eyes protrude.

Hyperthyroidism causes a very high metabolic rate, which causes the patient to lose a lot of weight. It can also cause the patient to become fidgety and often warm. Goitre is the name given to an enlarged thyroid and can occur in either hyperthyroidism, or hypothyroidism. Exophthalmic goitre usually occurs as a result of Graves' disease, which is a form of hyperthyroidism.

The body retains water in its fat deposits in this disease, and because of the water that is held in the orbital fat of the eye sockets, the protrusion of the eyes can be quite a marked symptom. Hyperthyroidism can be treated by the surgical removal of half of the thyroid gland.

Answer: True

Sadly this is true. Congenital hypothyroidism is what causes cretinism, and is when the baby does not produce enough thyroid hormones. This in turn is usually caused by maternal deficiency in iodine. Thyroid hormones are vital for growth of the whole body, particularly the nervous system, so a lack can have disastrous effects, such as those seen in cretinism.

As well as mental retardation and a dwarf stature, those affected by cretinism tend to have a low body temperature. It can be treated by administering thyroid hormones to the baby.

Answer: After pregnancy

"Postpartum" means "after birth" and usually refers to conditions seen in the mother after giving birth, such as postpartum depression. In pregnancy, the immune system has to modify itself to avoid the attack of the fetus as a foreign body, and after birth, this can cause problems - postpartum thyroiditis is seen in approximately 1 in 20 women after childbirth, and usually resolves itself.

It begins with a period of hyperthyroidism and ends as hypothyroidism. In some women, it does not get better in time, and they must receive treatment for hypothyroidism for the rest of their lives.

Answer: External carotid artery

As the thyroid is an endocrine gland, it has a rich blood supply from these arteries. The superior thyroid artery branches from the external carotid artery, as stated in the question, while the inferior thyroid artery branches from the subclavian artery. Each artery runs into the thyroid by a nerve; the superior by the external laryngeal nerve, and the inferior by the recurrent laryngeal nerve.

This can cause problems when the gland is surgically removed. Because of the rich blood supply, the arteries are usually ligated to control bleeding, but this can cause damage to the laryngeal nerves.

This in turn can cause an inability to speak due to paralysis of one side of the larynx. Sometimes the nerves regrow, but often they do not, so the patient has to relearn how to talk using only one side of their larynx.