Internal vs External Respiration
It has been a common mistake that people more often believe that respiration is just taking oxygen in and letting carbon dioxide out of the body. However, there are many more steps and processes involved than those in respiration. Respiration mainly has two processes known as the external and internal; in other words, breathing and actual respiration respectively. Both these are interrelated yet, different physiological processes. Breathing occurs first, and respiration takes place next. The places at which these two processes take place are different as well as the pathways of internal and external respiration are much different. Therefore, it would be interesting to discuss the differences in detail about both these processes.
Internal respiration is the process of breaking down food in the presence of oxygen at acellular level to produce energy. Internal respiration is an active process, as it requires energy. It uses oxygen to produce energy and produces carbon dioxide and water as waste products.
Internal respiration is a metabolic process that takes place in cells, where glucose from food reacts with breathing oxygen to produce biochemical energy in the form of Adenosine triphosphate, abbreviated as ATP. This energy is extremely useful to perform all the biological processes except thinking or dreaming. In addition to glucose, amino acids and fatty acids are also commonly used nutrients for respiration with cellular oxygen.
Water, ammonia, and carbon dioxide are waste products of internal respiration. Mostly water and carbon dioxide move out of the body via breathing, while ammonia excretes with urine. Respiration is an involuntary process, which the animal cannot control. However, internal respiration could be either aerobic or anaerobic. Aerobic respiration involves oxygen in the process, whereas there is no oxygen involved in anaerobic process.
External respiration is the process of taking oxygen into and expelling carbon dioxide from the body. External respiration is essential for life as it supplies oxygen to extract energy from food via internal or cellular respiration. Additionally, it removes carbon dioxide, which is a waste product of respiration. In addition, external respiration removes excess water from the body through exhalation.
External respiration is a physical process consisting of inhalation, exhalation, and relaxation. Inhalation is an active process while exhalation is passive. External respiration involves two stages known as ventilation and gas exchange. Ventilation is the movement of the air in and out of the lungs. Gas exchange takes place in the alveoli of the lungs. Two things happen during gas exchange; oxygen goes into blood and carbon dioxide diffuses out into lungs.
External respiration is a voluntary action, which the animal can control. However, animals do not always voluntarily breathe, but it is an ever happening involuntary process as the centers in the brainstem automatically regulate the external respiration.
What is the difference between Internal and External Respiration?
• External respiration is a mechanical process, but internal respiration is a chemical process.
• External respiration is mainly the bulk exchange of gases in and out of the body, while internal respiration is the process of breaking down of nutrients with oxygen to produce energy.
• External respiration occurs between body and external environment whereas internal respiration takes place in cellular level.
• External respiration involves both active and passive processes, but internal respiration is only an active process.
• External respiration is both voluntary and involuntary, while internal respiration is always an involuntary process.
• Internal respiration produces energy and waste products, but nothing except gas exchange and voice producing in external respiration takes place.