At age 85, Lyle's immune system does not respond to vaccines as well as it did when he was younger. The atrophy of which endocrine gland is likely responsible for this? Thymus Which organ is responsible for synthesizing atrial natriuretic peptide? The heart Mineralcorticoid is to aldosterone as glucocorticoid is to ____. Cortisol One of the least complicated of the endocrine control systems directly responds to changing blood levels of ions and nutrients. What is this mechanism? Humoral stimulation Thyroid hormone enters target cells in a manner similar to _____. steroid hormones Normal development of the immune response is due in part to hormones from the ____. Thymus gland The most important mineralcorticoid regulator of electrolytes in extracellular fluid is _____. Aldosterone Lisa starts to feel hungry and worries her blood sugar level may be dropping. What hormone helps prevent a drop in blood sugar level? Glucagon Steroid hormones exert their action by _____. entering the nucleus of a cell and initiating or altering the expression of a gene Aldosterone _____. functions to increase sodium reabsorption Which of the following is NOT a parathyroid gland mechanism to maintain adequate levels of blood calcium? inhibition of calcitonin synthesis A man has been told he is NOT synthesizing enough FSH and may be unable to father a child. Chose the correct statement to explain this problem. FSH stimulates sperm production in the testes. The single most important regulator of calcium levels in the blood is ____. Parathyroid hormone Oxytocin _____. release is an example of a positive feedback mechanism. ADH _____. secretion is inhibited by alcohol Which of the following is NOT a category of endocrine gland stimulus? enzymatic