Thyroid Disorders: Hypo and Hyperthyroidism — NEET Biology
📚 Practice ConceptIn adult women, hypothyroidism may cause menstrual cycle to become irregular. Due to cancer of the thyroid gland or due to development of nodules of the thyroid glands, the rate of synthesis and secretion of the thyroid hormones is increased to abnormal high levels leading to a condition called hyperthyroidism which adversely affects the body physiology.
Which of the following statements regarding the thyroid gland and its hormones are NOT correct? S1: The thyroid gland is composed of two lobes interconnected by an isthmus and synthesizes only two hormones, T3 and T4. S2: Iodine is an essential element for the normal rate of synthesis of T3 and T4 hormones by the thyroid gland. S3: Hyperthyroidism, often due to cancer or nodules, leads to increased basal metabolic rate and is exemplified by Graves' disease. S4: Thyrocalcitonin (TCT) is a steroid hormone that works to elevate blood calcium levels. S5: Hypothyroidism in adult women can lead to irregular menstrual cycles and mental retardation in the offspring if occurring during pregnancy.
View solution & NCERT explanation
Correct answer: A — S1 and S4 only
S1 is incorrect. The thyroid gland synthesizes T3, T4, and also secretes Thyrocalcitonin (TCT). "These follicular cells synthesise two hormones, tetraiodothyronine or thyroxine (T4) and triiodothyronine (T3). Thyroid gland also secretes a protein hormone called thyrocalcitonin (TCT)". S2 is correct. "Iodine is essential for the normal rate of hormone synthesis in the thyroid." S3 is correct. "Exopthalmic goitre is a form of hyperthyroidism, characterised by ... increased basal metabolic rate, and weight loss, also called Graves’ disease." S4 is incorrect. TCT is a protein hormone and decreases blood calcium levels. S5 is correct. "In adult women, hypothyroidism may cause menstrual cycle to become irregular. Hypothyroidism during pregnancy causes defective development and maturation of the growing baby leading to stunted growth (cretinism), mental retardation, ...deaf-mutism, etc." Therefore, S1 and S4 are NOT correct. This question evaluates the knowledge about hormones secreted by the thyroid gland and their chemical nature and functions.
What does NCERT say about adult women hypothyroidism may?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.