Digestive System Biology Access Course

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Task 1: A brief introduction to digestion (i.e. Why we need to digest food, in one paragraph). Also explain the main processes involved, use one short paragraph for each. (Criteria 1): Digestion is the breaking down of food and drink into a smaller part so the body can use them to build and nourish cells and to provide energy as the body cannot absorb food without being broken down into smaller pieces. When we eat our food it is broken down into nutrients then absorbed into the bloodstream, our body then discards the indigestible parts of the food, this process is called digestion. The oesophagus is a tube that passes through the chest and connects the mouth to the stomach. The stomach leads to the small intestine, which is a narrow long tube from which most of the food absorption into the bloodstream takes place. The reason why we need to digest our food is because we need various molecules from the food we eat. We need carbohydrates for energy; we need amino acids to build protein. We also need various nutrients like vitamins and minerals. There are six main parts in the digestive system. We start off the process of digestion by; 1) The first part of digestion is ingestion. The mouth is where the digestion starts and it is adapted to receive food by ingestion. This is a voluntary act where food is placed in the mouth to be swallowed. 2) This is then followed by propulsion. This is where food moves along the alimentary canal. This includes swallowing and peristalsis which is involuntary. This is where the food moves along the muscle contractions of the alimentary tract. It consists of alternation and contraction of smooth muscle in the wall of the GI tract to squeeze food downwards. 3) Mechanical digestion consists of a physical process of breaking food into smaller pieces through mastication (chewing of food) before being broken

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