1 lactase intolerance, and. 2  malabsorption of certain foods. 3  Much of the gas generated is due to microbial breakdown of foods so that gases, for example, hydrogen, carbon dioxide, and methane are generated; the odor is from other trace waste gases or compounds such as skatole and sulfur-containing substances.
Best Answer: Blood enters the heart through the right atrium, it then goes into the right ventricle to be pumped via the pulmonary artery to the lungs to be re-oxygenated. After that it heads, via the pulmonary vein, to the left atrium in the heart to be pumped around the rest of the body again via the aorta.
After the blood receives oxygen, it returns to the left side of the heart, the left atrium. After collecting in the left atrium, it is pumped into the left ventricle, and from there it is pumped into the aorta, the largest blood vessel in the body. From the aorta, blood courses throughout the body through its arteries. For blood to go in only one direction, forward, it must pass through the heart valves, which function as one-way doors, opening and shutting with each beat of the heart. Just as there are four chambers to the heart, there are four heart valves.