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Digestive system

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• Digestive system

• What happens in mouth? • Saliva-has amylase to breakdown carbohydrates • Teeth breakdown the food • 1 st is chemical digestion • 2 nd is mechanical digestion

• Digestion involves mixing food with digestive juices, moving it through the digestive tract, and breaking down large molecules of food into smaller molecules. • Digestion begins • in the mouth, when you chew and swallow, and is completed in the • small intestine.

Movement of food in digestive tract • Food moves from one organ to the next through muscle action called • peristalsis. • Peristalsis looks like an ocean wave traveling through the muscle. The muscle of the organ contracts to create a narrowing and then propels the narrowed portion slowly down the length of the organ.

What does pancreas do? • • The pancreas produces chemicals that are crucial to proper digestion and blood sugar regulation. Important hormones secreted by the pancreas include • insulin and • glucagons, • • • which maintain the appropriate levels of sugar throughout our body. The parts of the pancreas responsible for the production of hormones are called the Islets of Langerhans, which are small clusters of cells liver stores glucose as GLYCOGEN. Glucagon breaks down the glycogen variety of sugar and releases its components into the blood. INSULIN then appears at the site of cells to help them easily absorb the sugar. This is the process that maintains a non-diabetic's blood sugar at healthy levels.

How does pancreas regulate blood sugar levels? • By making the two hormones • insulin and glucagon. • together, they regulate the level of glucose in the blood. Insulin • lowers • the blood sugar level and increases the amount of glycogen (stored carbohydrate) in the liver. • Glucagon slowly • increases the blood sugar level if it falls too low.

2 nd job? • In its second function, the pancreas • creates digestive juices. • These fluids must break down nutrients that the stomach's acids weren't effective at metabolizing. • Since the pancreas is so close to the small intestine, there are many ducts streaming from its head to carry the enzymes to the duodenum, which is the beginning of the intestine. • These enzymes include lipase, which digests fat, trypsin, or protein, and one that works on carbohydrates, amylase. The resulting nutrients are distributed further down the small intestine

What does liver do? • What does your liver do? • • The liver is one of the largest organs in your body. It has many important jobs. • It cleanses the body of toxins (like alcohol) and bacteria. • It produces bile that helps digest food. • The liver also stores sugar as _______.

• • Absorption and Transport of Nutrients Most digested molecules of food, as well as water and minerals, are absorbed through the small intestine. The mucosa of the small intestine contains many folds that are covered with tiny fingerlike projections called villi. In turn, the villi are covered with microscopic projections called microvilli. These structures create a vast surface area through which nutrients can be absorbed. Specialized cells allow absorbed materials to cross the mucosa into the blood, where they are carried off in the bloodstream to other parts of the body for storage or further chemical change. This part of the process varies with different types of nutrients.