Question

Explain the integrated sympathoadrenal response to exercise.

Answer 1

Ans:

The integrated sympathoadrenal response is a combined physiological response shown by sympathetic nervous system and the adrenal medulla in response to outside stimuli in an organism. Beginning in the sympathetic nervous system, an external stimulus affects the adrenal medulla and causes a release of catecholamines.

The primary function of the sympathoadrenal system is to help regulate the body's responses to environmental stimuli as these stimuli travel through the preganglionic nerve fibers that emerge from the thoracic spinal cord. Electrical impulses carried by the sympathetic nervous system are converted to a chemical response in the adrenal gland where, chromaffin cells contained in the adrenal medulla act as postganglionic nerve fibers that release this chemical response into the blood.

During exercise, the human body undergoes a stress related response in which excess of oxygen and energy is required for physical activity. The stress induced during exercise results in an increased production of hormones, epinephrine and norepinephrine, which are known for the body's "fight or flight" response. Further, the heart rate increases allowing more blood to pump through the body system and carry oxygen needed to enhance cardiorespiratory function.

With an increase in epinephrine and norepinephrine, sympathoadrenal activity results in an increase in glycogen which increases glucose release that is needed for energy. Glucose can undergo an increase in production due to elevated secretion of epinephrine. The mechanism lies in epinephrine being secreted by the adrenal medulla and activating glycogenolysis or promoting gluconeogenesis. As epinephrine has a greater effect in glucose production, norepinephrine can also increase glucose levels at high concentrations. It has even been found that norepinephrine may play a role in enhancing the uptake of glucose in skeletal muscle and adipose tissues.