Questionĭescribe the process of gaseous exchange at the muscles. They are made of semi-permeable membranes which allow oxygen and carbon dioxide to pass through them. Both the capillaries and alveoli walls are very thin - just one cell thick. As the blood moves through the capillaries in the alveoli, oxygen diffuses into it and carbon dioxide diffuses out of itĬapillaries surround the alveoli in the lungs. Haemoglobin carries oxygen to be exchanged at the working muscle and carbon dioxide to be exchanged at the lung. There is a high concentration of carbon dioxide in the blood and a low concentration in the alveoli, so carbon dioxide diffuses from the blood into the alveoli.īoth oxygen and carbon dioxide are capable of combining with an iron-rich protein in the blood called haemoglobin. There is a high concentration of oxygen in the alveoli and a low concentration of oxygen in the blood, so oxygen diffuses from the alveoli into the blood. The alveoli are surrounded by capillaries so oxygen and carbon dioxide diffuse between the air in the alveoli and the blood in the capillaries.ĭiffusion is the movement of gas from an area of high concentration to an area of low concentration. Importance of Oxygen Cycle Oxygen is one of the essential components required for the existence of life on Earth. Gaseous exchange occurs at the alveoli in the lungs and takes place by diffusion. During combustion or burning, oxygen reacts with carbon to form carbon dioxide gas. This decreases the size of the chest and increases the air pressure in the chest so air is forced out of the lungs.ĭuring exercise, this passive process of relaxation becomes active as the abdominal muscles pull the ribs downwards and inwards even further. The intercostal muscles relax so the ribs move inwards and downwards under their own weight. The diaphragm relaxes and moves back to its domed shape. When exercise begins, inspiration can be assisted by the pectoral muscles and the sternocleidomastoid which help to lift the ribs up and out even further. This increases the size of the chest and decreases the air pressure inside it which sucks air into the lungs. The intercostal muscles contract and move the ribs upwards and outwards. The diaphragm contracts and moves downwards. The intercostal muscles are found between the ribs and they control rib movement. When we breathe in, the alveoli gets filled with air containing oxygen. Alveoli are the small pouch-like air sacs in the lungs, these have thin walls (membrane) and are surrounded by a network of blood capillaries. The diaphragm is a sheet of muscle that separates the chest (or thoracic) cavity from the rest of the body. Solution Answer: The exchange of oxygen and carbon dioxide during respiration occurs in the alveoli of the lungs. Two important structures for breathing are the diaphragm and intercostal muscles. At the end of the bronchioles, the air enters one of the many millions of alveoli where gaseous exchange takes place.īreathing is the term given to the process of taking air into and out of the lungs.Each bronchus branches out into smaller tubes called bronchioles.Air enters the body and is warmed as it travels through the mouth and nose.Structure and function of the respiratory system Passage of air into the lungs
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