Fasting/starvation

The alanine cycle accomplishes the same thing as the Cori cycle, except with an add-on feature (Fig. 17-11). Under conditions under which muscle is degrading protein (fasting, starvation, exhaustion), muscle must get rid of excess carbon waste (lactate and pyruvate) but also nitrogen waste from the metabolism of amino acids. Muscle (and other tissues) removes amino groups from amino acids by transamination with a 2-keto acid such as pyruvate (oxaloacetate is the other common 2-keto acid). 

In the options above, each graph depicts the primary source of fuel used by the brain during fasting/starvation. For each condition listed below, select the most closely matched graph. 

Be able to give the metabolic processes that normally take place in the fed state, the three fasting-starvation states, and in insulin-dependent diabetes. 

Body Fuels Available during Fasting Starvation Alcohol... 

In prolonged fasting (starvation), changes occur in the use of fuel stores that permit survival for extended periods of time. 

C. Blood Glucose Levels during Prolonged Fasting (Starvation)... 

In other situations, stress factors such as emotional disturbances, fasting, starvation, or diabetes, are signals to the pituitary gland to release adrenocorticotropic hormone (ACTH), which acts both alone on tissues and stimulates secretion of other stress hormones by the adrenal glands. The net effects of these stress-responsive hormones are the tearing down (catabolism) of fat, muscle, and/or bone tissues, so as to provide essential nutrients for metabolism. 

---