If a blood clot forms, it can stop the blood flow. This can cause a heart attack or stroke. A heart attack occurs when the blood flow to a part of the heart is blocked by a blood clot. If this clot cuts off the blood flow completely, the part of the heart muscle supplied by that artery begins to die.
Digestion works by moving food through the GI tract. Digestion begins in the mouth with chewing and ends in the small intestine. As food passes through the GI tract, it mixes with digestive juices, causing large molecules of food to break down into smaller molecules.
Digestion Begins. Enzymatic digestion occurs primarily in the mouth, stomach and small intestine. Both physical and chemical digestion begin in the mouth: the process of chewing grinds up food and mixes it with saliva, which contains an enzyme called salivary amylase. Enzymes facilitate chemical reactions by binding to reactive molecules.