The digestive and excretory system is complex. The digestive system includes a gamut of organs responsible for digestion. The digestive system works by breaking down food into small bits and in the process, nourishment is absorbed by the cells. The food enters through the mouth and it is grinded by the teeth to form a paste. The enzyme present in saliva breaks the carbohydrates into small sugar particles. The food passes through the esophagus. This is the pipe which starts from the mouth and ends in the stomach.
The muscles of the esophagus contract and this helps the food pass smoothly through the passage. The contraction process of the esophagus is known as peristalsis. When food enters the stomach the muscles cause churning and then it mixes with acid present within the stomach. The acids activate enzymes and in the process proteins are broken down into amino acids. Then the food exits from the stomach and enters the small intestine. In this part of the body enzymes from the pancreas, the gall bladder and the liver mix with the food to be further broken down.
All essential carbohydrates are reduced to sugar units, proteins are crushed into amino acids and lipids are made up of glycerol and fatty acids. The proper breakdown of food helps in absorption by the blood. Tiny particles enter the primary blood system and are circulated to all major tissues and cells. Microscopic finger-like pieces of tissue called villi line the wall of the small intestine and help with absorption of nutrients.
The excretory system encompasses the process by which the humans get rid of excretory wastes in the form of feces. This is the best way homeostasis is maintained. In the process, toxic elements like harmful salts, carbon dioxide and urea are removed from the body. The liver too has a role to play in the excretory system. The extra amino acid contents present within the body are better converted into significant compounds and the liver is responsible for this. Urea is produced as a waste product and it is then removed from the main blood stream through the kidneys.
The kidney is a vital organ of the digestive and excretory system and it works well in filtering out waste water and checks with PHP balance in the blood. Thus, in order to stay fit and disease free you have to keep the entire system well by eliminating all possibilities of occasional disruptions.