Understanding The Human Body – Breathing and Respiration Part 1. Breathing and respiration are two completely different but interrelated body processes which assist body organs to function properly. Breathing is the physical process of exchanging gases whilst respiration is a chemical process which takes place at a cellular level and produces energy.
Breathing is a biophysical process that involves the exchange of gases through inhalation and exhalation.
Breathing is also called ‘external respiration’ as it is an external process of taking oxygen in and throwing carbon dioxide out via respiratory organs.
The process of breathing in all vertebrates consists of highly branches network of tubes that connect the nose and the alveoli.
Breathing in repetitive cycles where the number of respiratory cycles in a minute is called breathing or respiratory rate.
Under normal conditions, the rate and depth of breathing are controlled by several homeostasis mechanisms to maintain the partial pressure of oxygen and carbon dioxide in the blood.
The mechanism of breathing involves contraction and relaxation of several muscles present in the thoracic cavity because the lungs are not capable of inflating on their own.
In humans and most vertebrates, the inflation of lungs is brought by the contraction of the diaphragm and the intercostals muscles, causing the rib cage to rise upwards and outwards.
During inhalation, the air is taken in through the nose that passes through the nasal passage, the pharynx, the larynx to reach the respiratory tree.
The respirator tree begins with the trachea that is divided into several narrower branches. The number of branches differs with organisms as humans have about 23 branches, whereas the respiratory tree of a mouse has up to 13 branches.
The air thus passes through these branches and finally reaches the alveoli. The exchange of gases takes place in the alveoli where the oxygen is diffused into the blood present in the blood vessels, and the carbon dioxide from the blood is diffused into the alveoli.
The carbon dioxide is then exhaled when the diaphragm and other respiratory muscles relax, causing the lungs to contract. The exhalation is a passive process.
The air in the lungs then gets pushed up and out, which causes it to pass through the trachea and nasal passage back to the atmosphere.
Breathing is a voluntary process and thus requires energy. Lack of energy might result in difficulty in breathing.
Respiration is a biochemical process to release energy from organic compounds which are then used for performing different physical activities.
Respiration is also called ‘internal respiration’ as it is an internal process of breaking down complex organic compounds into carbon dioxide and water while releasing energy.
Respiration, unlike breathing, occurs in all living organisms.
It is an involuntary process that occurs automatically if all the reactants for the reactions are available.
Respiration takes place in the mitochondria of all the cells throughout the body.
Respiration is a metabolic process where glucose is oxidized in the presence of oxygen to form carbon dioxide and water.
Respiration can occur either in the presence of oxygen or in its absence. Respiration in the presence of oxygen is aerobic respiration, whereas the respiration in the absence of oxygen is anaerobic.
The reactions involved in cellular respiration are catabolic reactions which break down complex compounds into simple ones.
The process of respiration is dependent on various enzymes that catalyze different steps in the metabolic pathway. These enzymes regulate the rate and direction of these reactions.
These enzymes are present on the inner and outer mitochondrial membrane or in the cytoplasm. The enzymes for glycolysis are present in the cytoplasm, but the enzymes for Kreb’s cycles are present in the inner mitochondrial membrane.
Cellular respiration occurs through a number of cycles like glycolysis, Kreb’s cycle and electron transport chain. All of these reactions together result in a large amount of energy and oxidation of organic compounds.
The nutrients that are commonly used by organisms during respiration are carbohydrates, amino acids and fatty acids. The most common oxidizing agent is molecular oxygen, although other chemicals like sulphur and nitrogen can also be used.
Although respiration is mostly associated with the release of carbon dioxide gas, other forms of respiration like fermentation are also equally important.
Fermentation forms the basis of alcohol formation. Similarly, other anaerobic respiration processes like lactic acid fermentation and propionic acid fermentation are essential for the production of cheese and other milk products.
Respiration is an important metabolic process as it is mostly a passive process, resulting in a large number of ATPs.
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