Oxygen and Carbon Dioxide are the two gases being exchanged in the alveoli. Carbon Dioxide diffuses blood into the air, and oxygen diffuses from the air in the alveoli into the blood.
This is called purging. Purging is a situation when a person gets rid of ingested food <em>voluntarily</em>. This is in contrast to vomiting which is often involuntary. Purging is usually manifested by people with eating disorders such as <em>buliumia nervosa</em> and body dysmorphic syndromes.
<em>Starvation is the lack of nutrients due to reduced intake of food and constipation is reduced frequency of defecation associated with difficulty in defecation.</em>
