This document discusses respiration and the mechanics of breathing. It begins by defining respiration as the intake of air through inhalation and exchange of gases through exhalation. Breathing is controlled by respiratory centers in the brain and chemoreceptors that respond to oxygen, carbon dioxide, and hydrogen levels. Factors like exercise and stress can increase respiration while medications and temperature can decrease it. Abnormal breathing patterns include changes in rate, rhythm, depth, and sounds. Damage to the phrenic nerve that controls the diaphragm can impact breathing and may require a diaphragmatic pacemaker for treatment.