Respiratory System in Human Body
All physical and chemical reactions in which atmospheric air oxidizes food in the body cells resulting in production of energy and liberation of CO2 are included in respiration.
Types of Respiration
I. Anaerobic Respiration
When nutrients are oxidized without using O2 (also called fermentation).
In yeast, glucose forms ethyl alcohol and CO2.
In bacteria and muscles, glucose is converted into lactic acid. Endoparasites like Ascaris, Fasciola, Taenia also respire anaerobically.
II. Aerobic Respiration
Cells utilize O2 for oxidizing nutrients. O2 is used either from atmospheric air or from water.
It is found in most plants and animals.
It provides much more energy than the anaerobic one.
- External Respiration: Gaseous exchange of O2 and CO2 between blood and air (or water).
- Transport of gases to the tissues.
- Internal Respiration: Gaseous exchange between blood and tissues.
- Cellular Respiration: Oxidation of nutrients in the cells and liberation of energy.