How Living Organisms Breathe
♥ We breathe by ventilating our lungs regularly with fresh air.
♥ Air is sucked into the lungs when the ribs rise and when the diaphragm falls. The air is pushed out when the ribs fall and the diaphragm rises.
♥ The air we expire contains much more carbon dioxide and water vapour than the air we inspire.
♥ The composition of the air changes in the millions of microscopic air sacs called
which are found at the ends of the bronchial tree branches.
♥ Oxygen is carried all over the body by the blood to the tissues where it is used in a process called
♥ Respiration releases energy and produces carbon dioxide, a waste which must be eliminated from the body.
♥ The more energy we need the more we respire. Therefore, we breathe faster and deeper to obtain more oxygen and excrete more carbon dioxide.