Which one of the following processes accounts for the low level of proinsulin normally found in circulating blood? A.selective binding of proinsulin by A cells within the islet B.efficient endocytosis of proinsulin in the liver C.efficient conversion of proinsulin to insulin within maturing secretion granules D.efficient conversion of proinsulin to insulin before exit from the ER E efficient processing of proinsulin by a serum protease imediately after exocytosis Question#16 The hypophyseal portal veins comprise an essential route for releasing factor-nediated secretion of all the following pituitary hormones EXCEPT A.ACTH B.vasopressin C.prolactin D.growth hormone E.follicle stimulating hormone (FSH) Question#17 In response to decreases in seru calcium below normal levels,parathyroid chief cells A stop synthesizing parathyroid hormone B.stop processing proparathyroid hormone C.increase cell surface calciun receptors D.increase parathyroid hormone secretion E stop dividing Which one of the following alternatives represents the correct pathway for synthesis,storage and secretion of biogenic amines like noradrenaline (norepinephrine)? A.proteolysis from a polypeptide precursor.storage in granules.discharge by exocytosis B.synthesis in smooth ER and miotochondria,release through the plasm membrane without storage C.production by lysosomal degradation,diffusion through the plasna membrane without storage D.synthesis from decarboxylated amino acids,uptake into secretion granules,discharge by exocytosis E.production in the ER and passage through the intracellular transport pathway without storage of cholesteryl ester droplets? A.cells of the adrenal zona fasciculata B.A cells of the endocrine pancreas C.thyroid folliclar cellsWhich one of the following processes accounts for the low level of proinsulin normally found in circulating blood? A. selective binding of proinsulin by A cells within the islet B. efficient endocytosis of proinsulin in the liver C. efficient conversion of proinsulin to insulin within maturing secretion granules D. efficient conversion of proinsulin to insulin before exit from the ER E. efficient processing of proinsulin by a serum protease immediately after exocytosis -------------------------------------------------------------------------------- Question # 16 The hypophyseal portal veins comprise an essential route for releasing factor-mediated secretion of all the following pituitary hormones EXCEPT A. ACTH B. vasopressin C. prolactin D. growth hormone E. follicle stimulating hormone (FSH) -------------------------------------------------------------------------------- Question # 17 In response to decreases in serum calcium below normal levels, parathyroid chief cells A. stop synthesizing parathyroid hormone B. stop processing proparathyroid hormone C. increase cell surface calcium receptors D. increase parathyroid hormone secretion E. stop dividing -------------------------------------------------------------------------------- Question # 18 Which one of the following alternatives represents the correct pathway for synthesis, storage and secretion of biogenic amines like noradrenaline (norepinephrine)? A. proteolysis from a polypeptide precursor, storage in granules, discharge by exocytosis B. synthesis in smooth ER and miotochondria, release through the plasma membrane without storage C. production by lysosomal degradation, diffusion through the plasma membrane without storage D. synthesis from decarboxylated amino acids, uptake into secretion granules, discharge by exocytosis E. production in the ER and passage through the intracellular transport pathway without storage -------------------------------------------------------------------------------- Question # 19 which of the following cell types is easily recognized in the microscope by its rich cytoplasmic content of cholesteryl ester droplets? A. cells of the adrenal zona fasciculata B. A cells of the endocrine pancreas C. thyroid folliclar cells D. neurohypophyseal