Respiration is the process that your body uses to get energy out of the food you eat. Aerobic respiration is the process of getting food energy in the presence of oxygen. Aerobic respiration is the primary way that chemical energy is harvested from the food you eat. Breathing forms a critical component of aerobic respiration. Respiration requires that cells exchange gases with their surroundings, and breathing exchanges these gases between your blood and air outside your body.
Ventilation
Breathing and aerobic respiration involve ventilating your lungs. Ventilating requires inhalation and exhalation. Your diaphragm contracts and your rib cage expand when you inhale. The air that you inhale mixes with stale air that is already in your lungs. According to Gondar Design Science, the air you inhale contains approximately 20 percent oxygen, but the air in your lungs contains around 14 percent oxygen. Your diaphragm relaxes and your abdominal muscles push your lungs up when you exhale. The air that you exhale contains approximately 16 percent oxygen. Around 5.5 liters of air goes in and out of your body when you ventilate your lungs by inhaling and exhaling as deeply as you can.
Inhalation
You supply the oxygen required for aerobic respiration by inhaling, and drawing oxygen in through your nose or mouth. The oxygen that you inhale flows through your windpipe and into your lungs. Small air sacs called alveoli capture oxygen that flows into your lungs. Blood vessels known as capillaries surround the alveoli, and absorb oxygen into your blood stream. Oxygen in your blood flows to cells in tissues throughout your body during aerobic respiration.
Exhalation
Carbon dioxide must leave your body through your lungs during aerobic respiration. Your lungs have a large surface area that is very thin, which allows enough carbon dioxide to exit your body when you exhale. Billions of microscopic alveoli line the surface of your lungs. The alveoli absorb carbon dioxide through your capillaries as they distribute oxygen to your capillaries when you inhale. Your body expels carbon dioxide through your lungs when you exhale the carbon dioxide absorbed by the alveoli.
Muscles
Your diaphragm and intercostals are the skeletal muscles that facilitate breathing and aerobic respiration. Your intercostals form the muscle tissue between each of your ribs. A broad band of muscle that sits under your lungs forms your diaphragm. The diaphragm forms the base of an area known as the thoracic cavity by attaching to the lower part of your ribs, sternum and spine. Your diaphragm and intercostals are the primary skeletal muscles for supplying oxygen and expelling carbon dioxide when you breathe and during aerobic respiration.
