Respiration is an essential mechanism of the human body as it is responsible for producing energy. Subsequently, it helps to convert food into chemical energy to facilitate cellular activities.
Furthermore, it is responsible for supplying oxygen to cells and eliminating carbon dioxide from the system. Keeping these in mind, let’s proceed to find out respiration and the process of transport of oxygen and carbon dioxide in brief.
What is Respiration?
It is a catabolic process wherein living organisms inhale oxygen and exhale carbon dioxide, enabling the body to release required energy. Notably, the transport of gases takes place in blood cells.
Needless to say, the active transport of gases in blood cells depends mostly on the respiratory organs. For instance, pharynx, trachea, soundbox, bronchi, bronchioles, alveoli, etc. have a significant role in the human respiratory system.
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Test Your Knowledge:
_________ is responsible for the transport of respiratory gases.
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Digestive system
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Reproductive system
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Respiratory system
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Skeletal system.
Steps of Respiration
Several steps have to be completed to initiate and complete the transportation and diffusion process.
Following pointers highlight the carbon dioxide and oxygen transport steps in respiration.
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Pulmonary ventilation or breathing, which helps to draw in the atmospheric air and also allows releasing the carbon dioxide-rich air out.
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Diffusion of oxygen and carbon dioxide in the alveolar membrane.
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Transport of gases in blood.
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Transport of oxygen and carbon dioxide in blood cells and tissues.
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Absorption of oxygen by cells to initiate catabolic reactions.
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Release of carbon dioxide or cellular respiration
DIY: Find out about these steps in detail and write them down in your words.
Oxygen and Respiration
As much as 97% oxygen is transported by RBC in blood while the rest gets dissolved in plasma. Haemoglobin irreversibly mixes with oxygen to form oxyhaemoglobin; it is entirely dependent on the pressure of oxygen, carbon dioxide, temperature and concentration of H+.
The alveoli offer an ideal condition for the formation of oxyhaemoglobin. On the other hand, the tissues tend to harbour contrasting conditions which leads to dissociation of oxygen from the oxyhaemoglobin. On average, every 100 ml of oxygenated blood can deliver around 5ml of oxygen to tissues.
Carbon Dioxide and Respiration
Around 20-25% of carbon dioxide is transported through RBCs, and 70% is transmitted as bicarbonate. Notably, around 7% of dissolved carbon dioxide is transported through plasma.
Carbon dioxide gets bound with haemoglobin with the help of the partial pressure exerted by carbon dioxide and oxygen. As the concentration of carbon dioxide is high in the tissues, the process of binding carbon dioxide occurs automatically.
Next, the enzyme, carbonic anhydrase facilitates the reaction, wherein the carbon dioxide dissociates from carbamino-haemoglobin. As a result, the bicarbonates formed in tissues release carbon dioxide in alveoli. Every 100 ml of deoxygenated blood delivers around 4ml of carbon dioxide to alveoli.
Respiratory System Disorder
The mechanism of respiration is quite important in the human body, owing to the array of reactions it imitates and facilitates. However, often the respiratory system is subjected to some pathogenic conditions.
These following are some common respiratory diseases which bother human beings.
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Asthma.
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Emphysema.
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Pneumonia.
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Chronic bronchitis.
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Cystic fibrosis.
Find out more about the transport of oxygen and carbon dioxide in the respiratory system and respiratory disorders in detail straight from subject experts. Join our live online classes to get your doubts cleared from our faculties and improve your knowledge on these topics.
Transport of Oxygen and Carbon Dioxide through Respiration – At A Glance
1. Oxygen Transport: Oxygen is primarily transported through the blood by erythrocytes which contain a metalloprotein called haemoglobin, composed of four subunits with a ring-like structure containing one atom of iron bound to a molecule of heme. Heme binds oxygen such that each haemoglobin molecule is able to bind up to four oxygen molecules. Saturated haemoglobin is when all of the heme units in the blood are bound to oxygen and when only some heme units are bound to oxygen, haemoglobin is said to be partially saturated.
Oxygen–haemoglobin saturation/dissociation curve is a common way to depict the relationship of how easily oxygen binds to haemoglobin or dissociates from haemoglobin with respect to the partial pressure of oxygen. With the increase in partial pressure of oxygen, the haemoglobin binds more readily to oxygen. Also, once one molecule of oxygen binds to haemoglobin, binding of other molecules of oxygen to haemoglobin becomes easier. Other factors such as pH, temperature, the concentration of 2,3-bisphosphoglycerate, and the partial pressure of carbon dioxide can increase or inhibit the binding of haemoglobin to oxygen. The structure of the haemoglobin of the foetus is different from the adult haemoglobin, because of which foetal haemoglobin has a greater affinity for oxygen than adult haemoglobin.
2. Carbon Dioxide Transport: Carbon dioxide can be transported in the blood by any of the three different mechanisms, which are in the form of bicarbonate, or as carbaminohemoglobin or simply in dissolved carbon dioxide form in the blood. The carbon dioxide is transported for exhalation largely in the form of bicarbonate which is formed in erythrocytes. Bicarbonates ions are formed by the dissociation of carbonic acid which is formed by the combination of carbon dioxide with water in the presence of an enzyme called carbonic anhydrase. As the bicarbonate level rises in erythrocytes, it is exchanged with the chloride ions by passing through the membrane into the plasma by a mechanism known as chloride shift. Bicarbonate re-enters erythrocytes in exchange for chloride ions in the pulmonary capillaries, reversing the reaction with carbonic anhydrase, thereby forming carbon dioxide and water. The carbon dioxide diffuses out of the erythrocyte into the air through the respiratory membrane.