Enzymes and Digestion

Enzymes and Digestion:
The major parts of the digestive system are:
• The oesophagus, long digestive tract that carries the food from the mouth to the stomach. Adapted for transport, in ways such as being made up of a thick muscular wall.
• The stomach, a muscular sac with an enzyme producing inner layer. Function is to store and digest food. Has glands which produce enzymes to break down proteins, and also has glands that produce mucus, so it doesn’t digest itself.
• The small intestine, a long muscular tube where food is further digested by enzymes that are produced by it’s walls and by glands that secrete into it. The inner walls are folded into villi and these villi have even tinier projections called microvilli, which increase the small intestine’s surface area, which adapts it for it’s purpose of the absorption of the products of digestion into the bloodstream.
• The large intestine, is designed to absorb water, which makes the food in the large intestine more solid in consistency, and therefore, forming faeces.
• The rectum is the last section in the system. The faeces are stored in it before being removed by the anus the egestion (pooing.)
• The salivary glands, pass their secretions via a duct in the mouth, it contains amylase (salivary amylase) which breaks down starch into maltose.
• The pancreas, is a gland below the stomach, which makes pancreatic juice, it secretes into the stomach. It contains amylase to digest starch, protease to digest proteins, and lipase to digest lipids.

The digestive system breaks down food physically by, (if it is large), broken down into smaller chunks my structures such as teeth, this breaks it down into a larger surface area for chemical digestion. It is also churned by muscles into the stomach walls, which breaks it up more.
It is broken down chemically by enzymes, which break down large insoluble molecules into smaller soluble molecules.
The role of enzymes in digestion is by hydrolysis. The molecules are split up by adding water to the chemical bonds which breaks them. Enzymes are very specific, so more then one is needed to break down a large molecule. One enzyme splits a large molecule into sections, and these molecules are then hydrolysed into smaller molecules by one or more enzymes. Carbohydrases, Lipases, and Proteases, are the most important types of enzyme. After being broken down they are absorbed into the bloodstream, and carried around the body to the pats where they are needed.

1) a) The stomach is adapted for churning food by having muscles in the stomach wall, as when these contract, the food gets moved around. B) It is adapted to prevent the enzymes it produces from digesting the surface of the stomach by having glands that produce mucus to layer the surface.
2) Hydrolysis is the splitting of molecules into smaller ones by adding water to the chemical bonds that hold them together, which causes them to break.
3) The two structures that produce amylase is the salivary glands, and the pancreas.
4) The stomach does not have villi or microvilli as the stomach wall does not absorb anything, so an increase in surface area is not needed. Also, the food particles already have an increased surface area for chemical digestion from being churned.