Breathing is the mechanical process of taking freah air into the lungs and removing carbon dioxide from the lungs. Respiration is the chemical process which takes place in every cell to release energy from the simple sugars (e.g. glucose) by reacting the glucose with oxygen. The reaction produces carbon dioxide and water as by-products.
Respiration
Respiration involves:
- oxygen is taken to the muscles by the boold
- energy is released by the reaction of the simple sugars with oxygen
- carbon dioxide is taken back by the blood to be breathed out
There are aerobic and anaerobic respirations. Aerobic respiration requires oxygen and produces more energy than anaerobic respiration as the sugar is completely burnt:
glucose (C6H12O6) + oxygen (6O2) --> carbon dioxide (6CO2) + water (6H2O) + energy
Anaerobic respiration takes place without oxygen and release less energy. It takes place in muscles where there is less oxygen or when oxygen is used up faster than the body can take in (e.g. in a strenuous race). Instead of CO2, lactic acid is produced:
glucose --> lactic acid + energy
When anaerobic respiration is no longer required (e.g. at end of race), deep breathing continues to replace the oxygen used up. A marathon runner is paced such that there is no build up of oxygen debt but uses up oxygen at the rate at which it is taken into the body.
Energy is used for cell division, growth and repair as well as work, rest and play.
Breathing
The function of the lungs is to transfer oxygen to the blood and to remove waste carbon dioxide from the blood. The supply of the oxygen into the lungs is through the inhaled air (breathing in), and the removal of carbon dioxide from the lungs is through the exhaled air (breathing out).
The lungs consist branched tubes (bronchioles) ending in millions of tiny sacs called alveoli. The walls of the alveoli are extremely thin and there is a large surface area within them. Oxygen diffuses throught the alveoli into the blood from the heart, and carbon dioxide diffuses from the blood into the alveoli. Rich in oxygen, the blood is then returned to the heart and then circulate to other parts of the body, transporting oxygen to the cells and carbon dioxide back from the cells.
The mechanism of breathing is through the movement of the diaphragm. When the diaphragm is pulled down by muscles, the ribs move up and out and the chest volume increases so air can be taking in. When the disphragm relaxes, the ribs move down and in and the chest volume reduces to push air out.