Define exchange of gases between aloveli and blood capilaries
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Respiration occurs when there is an exchange of gases between a living thing and its environment. In the case of humans, the structure for gas exchange is called analveolus. The oxygen gas which is inhaled is exchanged for carbon dioxide gas-- a waste product that will be excreted when it is exhaled.
The respiratory system is composedof the nose, pharynx,larynx, trachea, bronchi, and lungs.Itis within the lungs that the millions of alveoli take part in gas exchange.
Air moves from the nose to the pharynx, which is the tube in the throat. From there, it enters the trachea which is held open by cartilaginous rings. This airway divides into two tubes calledbronchi. Each bronchus leads to each lung. Bronchi subdivide into bronchioles which get progressively smaller. Eventually, at the end of the bronchioles are the millions of alveoli which are surrounded by tiny capillaries-- blood vessels from the circulatory system. Because capillaries and alveoli are thin-walled, gas exchange can occur between them by theprocess ofdiffusion.
Oxygen can diffuse from high concentration in the alveoli to lower concentration in the blood stream by passing through the thin capillary walls. As long as a gradientis present, passive transport will occur. With carbon dioxide in higher concentration in the bloodstream relative to the amount in the alveoli, it will pass from the bloodstream to the alveoli also by diffusion.
When the muscle called the diaphragmlocated between the chest and abdominalcavity contracts, the chest cavity expands. This creates a difference in air pressure--it is greater outside the body relative to the inside. This causes the lungs to fill with air and inhalation occurs. When the diaphragm muscle relaxes, the size of the chest cavity decreases. There willbe greater air pressure inside the body relative to the outside. This allows air to be pushed out of the lungs and exhalation occurs.
Breathing is regulated by the medulla oblongata inthe brain. As carbon dioxide levels rise, nerve signals are sent to the diaphragm to increase its contractions which regulates breathing rate.
The respiratory system is composedof the nose, pharynx,larynx, trachea, bronchi, and lungs.Itis within the lungs that the millions of alveoli take part in gas exchange.
Air moves from the nose to the pharynx, which is the tube in the throat. From there, it enters the trachea which is held open by cartilaginous rings. This airway divides into two tubes calledbronchi. Each bronchus leads to each lung. Bronchi subdivide into bronchioles which get progressively smaller. Eventually, at the end of the bronchioles are the millions of alveoli which are surrounded by tiny capillaries-- blood vessels from the circulatory system. Because capillaries and alveoli are thin-walled, gas exchange can occur between them by theprocess ofdiffusion.
Oxygen can diffuse from high concentration in the alveoli to lower concentration in the blood stream by passing through the thin capillary walls. As long as a gradientis present, passive transport will occur. With carbon dioxide in higher concentration in the bloodstream relative to the amount in the alveoli, it will pass from the bloodstream to the alveoli also by diffusion.
When the muscle called the diaphragmlocated between the chest and abdominalcavity contracts, the chest cavity expands. This creates a difference in air pressure--it is greater outside the body relative to the inside. This causes the lungs to fill with air and inhalation occurs. When the diaphragm muscle relaxes, the size of the chest cavity decreases. There willbe greater air pressure inside the body relative to the outside. This allows air to be pushed out of the lungs and exhalation occurs.
Breathing is regulated by the medulla oblongata inthe brain. As carbon dioxide levels rise, nerve signals are sent to the diaphragm to increase its contractions which regulates breathing rate.
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1. At first the oxygen enters the trachea.
2. It makes its way to the alveoli.
3. The alveoli is covered with many capillaries.
4. The thin walls of cappilaries and alveoli makes it possible for the oxygen to pass from alveoli to the cappilaries.
5. From the cappilaries the oxygen makes its way to the heart and then various parts of body.
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2. It makes its way to the alveoli.
3. The alveoli is covered with many capillaries.
4. The thin walls of cappilaries and alveoli makes it possible for the oxygen to pass from alveoli to the cappilaries.
5. From the cappilaries the oxygen makes its way to the heart and then various parts of body.
Hope this helps you...
Pl mark as brainliest if it does...
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