First, air goes to your lungs. There are tiny sacs that can hold air in them. When the air goes to your lungs, the sacs fill up with air and oxygen from the air enters the blood stream. As the blood goes round the body the oxygen is used by cells and muscles to combine with blood sugar to produce energy, and carbon dioxide is produced as a result. When the CO2 reaches the lungs it is transferred into the air sacs and out into the atmosphere.
Diffusion.
Pulmonary ventilation ensures that your alveoli are supplied with oxygen and that the carbon dioxide arriving from your blood stream is removed. The gas exchange process occurs between blood and alveolar air across the respiratory membrane by diffusion which occurs in response to concentration gradients.
In humans and mammals, respiratory gas exchange or ventilation is carried out by mechanisms of the heart and lungs. The blood is subjected to a transient electric field (QRS waves of the EKG) in the heart, which dissociates molecules of different charge. The blood, being a polar fluid, aligns dipoles with the electric field, is released, and then oscillates in a damped driven oscillation to form J or Osborn Waves, T, U, and V waves. The electric field exposure and subsequent damped driven oscillation dissociate gas from hemoglobin, primarily CO2, but more important, BPG, which has a higher affinity for hemoglobin than does oxygen, due in part to its opposite charge. Completely-dissociated hemoglobin (which will even effervesce if the electric field is too strong - the reason defibrillation joules are limited, to avoid bubble emboli that may clog vessels in the lung) enters the lung in red blood cells ready to be oxygenated. Convection occurs over the majority of the transport pathway. Diffusion occurs only over very short distances. The primary force applied in the respiratory tract is supplied by atmospheric pressure. Total atmospheric pressure at sea level is 760 mmHg (101 kPa), with oxygen (O2) providing a partial pressure (pO2) of 160 mmHg, 21% by volume, at the entrance of the nares, a partial pressure of 150 mmHg in the trachea due to the effect of partial pressure of water vapor, and an estimated pO2 of 100 mmHg in the alveoli sac, pressure drop due to conduction loss as oxygen travels along the transport passageway. Atmospheric pressure decreases as altitude increases, making effective breathing more difficult at higher altitudes. Higher BPG levels in the blood are also seen at higher elevations, as well.
•The gaseous exchange takes place in the lungs by diffusion through the alveolar surface. Diffusion occurs when molecules move from an area of high concentration (of that molecule) to an area of low concentration.
•This occurs during gaseous exchange as the blood in the capillariessurrounding the alveoli has a lower oxygen concentration of Oxygen than the air in the alveoli which has just been inhaled.
•Both alveoli and capillaries have walls which are only one cell thick and allow gases to diffuse across them.
•The same happens with Carbon Dioxide (CO2). The blood in the surrounding capillaries has a higher concentration of CO2 than the inspired air due to it being a waste product of energy production. Therefore CO2 diffuses the other way, from the capillaries, into the alveoli where it can then be exhaled.
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alveoli
Rattlesnakes have lungs and gas exchange occurs there.
Gas exchange occurs in the alveoli of the lungs. These tiny air sacs are surrounded by capillaries where oxygen from the air can enter the bloodstream and carbon dioxide can be removed from the blood.
alveolus
The exchange of gases occurs at the ends of the airways in the lungs. Here tiny sacs called alveoli connect with tiny blood vessels and here exhaust gas [carbon dioxide] is exchanged for fresh gas [oxygen].
Gas exchange occurs across the respiratory membrane of the alveoli; however, the short answer is simply alveoli
The exchange of gases between blood and air occurs in the alveoli of the lungs. Oxygen from the air diffuses into the bloodstream, while carbon dioxide from the blood diffuses into the air in the alveoli to be exhaled.
The gas exchange between carbon dioxide and oxygen occurs.
The alveoli are small sacs within the lungs where gas exchange occurs. They are located at the ends of bronchiole branches.
You use your lungs to breath. Your heart pumps the blood round your body (including into and out of the lungs where gas exchange occurs when you breath).
Alveoli- these are the small sac-like structures where gas exchange occurs with the blood. Its creates an ideal site for gas exchange between the air in the lungs and the blood in the capillaries.
Gas exchange also occurs in the alveoli of the lungs, where oxygen from the air is taken up by red blood cells and carbon dioxide is released. Additionally, gas exchange occurs in the gills of fish, where oxygen from water is absorbed by blood vessels and carbon dioxide is released.