Chapter 19 Thyroid Hormones PDF

Chapter 19 1. What is the primary function of thyroid hormones in the body? A) Regulation of calcium levels in the blood B) Stimulation of insulin secretion C) Control of body temperature D) Maintenance of optimal metabolism in tissues E) Regulation of adrenal gland function 2. Which hormone stimula...

Chapter 19 1. What is the primary function of thyroid hormones in the body? A) Regulation of calcium levels in the blood B) Stimulation of insulin secretion C) Control of body temperature D) Maintenance of optimal metabolism in tissues E) Regulation of adrenal gland function 2. Which hormone stimulates the secretion of thyroid-stimulating hormone (TSH) from the anterior pituitary? A) Thyrotropin-releasing hormone (TRH) B) Corticotropin-releasing hormone (CRH) C) Growth hormone-releasing hormone (GHRH) D) Luteinizing hormone-releasing hormone (LHRH) E) Prolactin-inhibiting hormone (PIH) 3. How are thyroid hormones synthesized in the thyroid gland? A) Thyroglobulin is synthesized in the blood and transported to the thyroid gland. B) Thyroid hormones are directly synthesized from iodine absorbed from the diet. C) Thyroglobulin is synthesized in the thyroid cells and secreted into the colloid, where it undergoes iodination. D) Thyroid hormones are synthesized from cholesterol precursors in the thyroid follicles. E) Thyroid hormones are synthesized from amino acids in the thyroid follicles. 4. What is the function of thyroid peroxidase in thyroid hormone synthesis? A) Regulation of iodine excretion from the thyroid gland B) Conversion of thyroglobulin into thyroid hormones C) Oxidation and iodination of tyrosine residues on thyroglobulin D) Secretion of thyroid hormones into the bloodstream E) Transport of iodine from the bloodstream into thyroid cells 5. How do thyroid hormones exert their physiological effects? A) By directly stimulating insulin secretion B) By inhibiting thyroid-stimulating hormone (TSH) secretion C) By binding to plasma proteins and altering their structure D) By acting on target tissues in their free form E) By promoting the synthesis of thyroglobulin in the thyroid gland 6. True or False (T/F) 7. Albumin has the smallest capacity to bind T4 among the plasma proteins. 8. False 9. Thyroxine-binding globulin (TBG) has the largest capacity to bind T4 among the plasma proteins. 10.False 11.Transthyretin has a longer half-life compared to thyroxine-binding globulin (TBG). 12.True 13.Most of the circulating T4 is bound to albumin. 14.False 15.Deiodination of T4 primarily occurs in the liver. 16.True 17.Circulating levels of pituitary TSH are primarily regulated by thyroxinebinding globulin (TBG). 18.False 19.Removal of the pituitary gland leads to thyroid function stimulation. 20.False 21.Prolonged TSH stimulation can lead to thyroid enlargement, known as a goiter. 22.True 23.What is the primary form of thyroid hormone found in plasma? a) T3 b) Free T4 c) T4 bound to TBG d) T3 bound to albumin e) T4 bound to transthyretin 24.Which plasma protein has the largest capacity to bind T4? a) Thyroxine-binding globulin (TBG) b) Albumin c) Transthyretin d) Thyroxine-binding prealbumin e) Cortisol-binding globulin 25.What percentage of circulating T4 is converted to T3 in adult humans? a) 5% b) 13% c) 25% d) 45% e) 65% 26.How are thyroid hormones primarily regulated in the body? a) By circulating levels of T3 b) By variations in plasma albumin levels c) By pituitary thyroid-stimulating hormone (TSH) d) By the activity of transthyretin in tissues e) By adrenal gland secretion 27.What is the term for the enlargement of the thyroid gland due to prolonged TSH stimulation? a) Thyroiditis b) Thyrotoxicosis c) Goiter d) Hypothyroidism e) Hyperthyroidism