Question

You have just eaten a raisin.  It is in your mouth now.  Where does it go from here?  Follow all the way through the digestive system

Answer 1

The digestive system is made up of the gastrointestinal tract—also called the GI tract or digestive tract—and the liver, pancreas, and gallbladder. The GI tract is a series of hollow organs joined in a long, twisting tube from the mouth to the anus. The hollow organs that make up the GI tract are the mouth, esophagus, stomach, small intestine, large intestine, and rectum. The liver, pancreas, and gallbladder are the solid organs of the digestive system.

Mouth is a part of digestive system. It is the place where chewing or mastication of food occurs in which food is mixed with saliva which contains an ezyme salivary amylase starts breaking down long carbohydrate molecules as soon as you put food in your mouth. Salivary lipase is also secreted in saliva which is responsible for about 10-30% of lipid digestion in stomach. The food is then swallowed from where it goes to stomach through oesophagus.

In stomach, the enzyme pepsin starts breaking down proteins into smaller chains of amino acids When pepsin starts acting on the proteins in swallowed food, a hydrolysis reaction occurs, which breaks apart the long protein chains (polypeptides) into smaller pieces (dipeptides or peptides). When pepsin is secreted, it is in an inactive form of pepsinogen. The stomach slowly empties its contents, called chyme, into the small intestine.

The muscles of the small intestine mix food with digestive juices from the pancreas, liver, and intestine, and push the mixture forward for further digestion. The walls of the small intestine absorb water and the digested nutrients into your bloodstream. As peristalsis continues, the waste products of the digestive process move into the large intestine. Waste products from the digestive process include undigested parts of food, fluid, and older cells from the lining of your GI tract.

The large intestine absorbs water and changes the waste from liquid into stool. Peristalsis helps move the stool into rectum. The lower end of large intestine, the rectum, stores stool until it pushes stool out of the it during a bowel movement.