Question

During exercise, epinephrine and norepinephrine are released from the adrenal medulla. Epinephrine and norepinephrine have the same effect on plasma glucose levels as glucagon. Explain how epinephrine and norepinephrine affect plasma glucose and why this is important during exercise.

Answer 1

Answer and explanation:

Epinephrine and norepinephrine are two hormones that are released from the adrenal medulla when the body is under stress (like during exercise, for example) as a part of the sympathetic response.

These hormones have many functions and they all work together to prepare the individual for a fight or flight response - like increasing heart rate and producing bronchodilatation. One of these functions is the rise of glucose levels in blood which is important for this substance to reach several tissues, like the skeletal muscle. The skeletal muscle will make use of this glucose to produce ATP and generate the required energy for muscle contraction through a process called glycolysis, which is key for the fight or flight response mentioned above.

When we exercise, glucose levels rise thanks to these hormones so the skeletal muscle can have enough energy to contract and move as we want. If the exercise is too intense or prolongued, glucose levels will drop and other fuels will be needed to sustain this activity, like stored glycogen and fat.