Endocrine practice problems

Endocrine practice problems - BMED 3100: Systems Physiology...

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BMED 3100: Systems Physiology Endocrine Practice Problems 1. The following exercise is based on the hypothetical endocrine control system shown below, which regulates the plasma concentration of the hormone H. Determine the consequences of each situation on the hormone concentration in the blood ([H]) and the hormone EFFECT (the gross action of a hormone). Assume that the condition described is maintained for a long period of time. Fill out the table by predicting the changes in each situation in two time periods: (1) the immediate consequences and (2) the steady state consequences. Use ++ for a large increase, + for a small increase, -- for a large decrease, - for a small decrease, and 0 for no change or a return to the initial condition. Situations: a. [X] is increased. Draw a graph of [H] versus time starting before the increase in [X] and continuing into the new steady state. b. The biochemical pathways that enable X to stimulate H secretion are partially inhibited. c. The number of H receptors is decreased. d. The endocrine cell response to the EFFECT is facilitated. e. The plasma carrier concentration, ]C], is suddenly increased. Draw a graph of [H] and [HC] on the same time axis starting before the increase in [C] and continuing to the new steady state. f. The hormone binding constant of C is decreased. g. Liver or renal failure leads to a decrease in H inactivation or excretion. Target c Endocrine cell b Liver inactivation & renal excretion g EFFECT - d [X] a [H] + [C] [H-C] e f H=hormone product of endocrine cell C=specific carrier of hormone H X=normal stimulus to the endocrine cell Lowercase letters refer to situations
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BMED 3100: Systems Physiology Situation Immediate Consequences Steady-State [H] EFFECT [H] EFFECT a ++ ++ + + b -- -- 0/- 0/- c ++ -- + 0/- d -- -- - - e -- -- 0 0 f ++ ++ 0 0 g ++ ++ 0/+ 0/+ a. An increase [X] immediately stimulates the endocrine cell to secrete more H. Hence, plasma [H] increases. The increased [H] stimulates the target more, causing the EFFECT to increase. The increased EFFECT then inhibits endocrine cell H secretion (negative feedback). That in turn causes plasma [H] to fall, lowering the EFFECT from its previous high. Neither [H] nor the EFFECT, however, can return to normal. If they did, the original disturbance
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This note was uploaded on 01/12/2012 for the course BMED 3110 taught by Professor Staff during the Spring '08 term at Georgia Institute of Technology.

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Endocrine practice problems - BMED 3100: Systems Physiology...

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