ExplanationA. True. If the sensitiv

ExplanationA. True. If the sensitivity to Cortisol is reduced, hypothalamus increases CRHsecretion causing the pituitary gland to increase ACTH secretion. This results inincreased Cortisol secretion. High levels of Cortisol cause increasing plasma glucoseconcentration, which in turn simulates insulin secretion. If the sensitivity of ACTHreceptors is reduced, the adrenal glands become smaller leading to decrease in bothplasma Cortisol and glucose concentration. Low level of plasma glucoseconcentration reduces insulin secretion.B. False. If sensitivity to thyroxine is increased, hypothalamus reduces TRHsecretion causing the pituitary gland to reduce TSH secretion, which in turn reducesthyroxine secretion. Low levels of thyroxine causes both low metabolic rate and lowbody temperature. If the sensitivity to TRH is increased, the pituitary glandincreases TSH secretion, which in turn stimulates thyroxine secretion. High level ofthyroxine cause both high metabolic rate and high body temperature.C. False. Propylthiouracil causes the levels of thyroxine to fall, and this in turnincreases TSH secretion. High levels of TSH cause hypertrophy of the thyroidgland. Low levels of thyroxine lead to higher body weight.D. False. Increased plasma level of CRH tends to increase the size of pituitarygland and ACTH secretion, and this in turn stimulates the adrenal gland to develop.Increased plasma level of TSH tends to increase thyroxine secretion. High level ofthyroxine inhibits the secretion of TRH leading to decrease in the size of thepituitary gland, without affecting the adrenal gland.R e f e r e n c eGuyton, A.C and Hall, J.E, Physiology Review, 2006, pp.235.