Feedback systems respond to low glucose levels by stimulating the release of hormones designed to mobilize stored glucose, including glucagon, epinepherine, norepinepherine, growth hormone, and cortisol. These hormones are similar to those released during "fight or flight," leading to autonomic symptoms of shakiness, pounding/racing heart, nervousness, anxiety, perspiration, tingling, feeling hungry, and sensing that blood sugar is low. At extremely low glucose levels, manifestations of altered brain function appear, such as confusion, fatigue, drowsiness, warmth, difficulty with speech, loss of coordination, and unusual behavior.
The preferred energy source for the brain is glucose. What manifestations can be expected when adequate levels of glucose are unavailable?