The answer is G cells. Of the 4 general gastric cell types, G cells are classified as enteroendocrine cells. G cells primarily secrete gastrin, and work with gastric chief cells<span> and </span>parietal cells in order to regulate the acid levels in the stomach.
Through the process of respiration , in lung the carbon dioxide from the blood is exchanged with oxygen.
The smallest dunctional unit if the lung is the alveoli
At this level the gases are exchange through the capillaries present close to the alveoli.
The concentration gradient ,meaning the greater amount of oxygen present in the lungs and greater amount of carbon dioxide in the blood creates a gradient that allow the movment of oxygen into the blood and carbon dioxide in the alveoli through the membrane .
Partial pressure created allows the easy movement .The carbon dioxide get into the trachea and expelled through nose and mouth.
