The body goes through absorptive and postabsorptive statesthroughout the course of 24 hours, as illustrated in Figure 25-11in your textbook. The nutrient pools (glucose, amino acid, andfatty acid) illustrated in Figure 25-1 vary in size during thesestates as the body absorbs these nutrients from food, uses them forenergy production, puts them into or releases them from storage, orbuilds/breaks down body structure.The body has multiplehormonally-driven mechanisms by which to maintain a relativelyconstant glucose pool in order to ensure that adequate glucose isalways available for the brain.  Neurons rely almostexclusively on glucose and cannot use fatty acids or amino acids asan alternate source.

The mass balance equation can be applied to the glucosepool.  Recall that the equation states that in order tomaintain balance of a particular substance, the intake of thatsubstance + its metabolic production must equal excretion of thatsubstance + metabolic removal of that substance.

Intake + metabolic production = Excretion + metabolic removal

1. Your first task is to apply the mass balance equation to themaintenance of the glucose pool during the absorptive andpostabsorptive states.  

For each state, you need to explainhow each of the parts of the equation contribute toincreases/decreases in the glucose pool, and the internalmechanisms that are employed to counteract those changes to restorebalance. As part of your explanation, you need to include thespecific organs/tissues, hormones, and metabolic processes that areinvolved.  For each hormone, include what leads to itsrelease, cell types it targets, and what it stimulates the targetsto do.

1. Your second task is to apply the mass balance equation to theregulation of blood glucose, or lack thereof, in someone whosuffers from diabetes mellitus.   Describe whatpart(s) of the equation are not functioningproperly.  Uncontrolled diabetes mellitus is associatedwith a number of classic symptoms:  excessive hunger andthirst, weight loss, and excessive urination.  Explainthese symptoms by applying the mass balance equation, absorptivevs. postabsorptive states, and nutrient pools.