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Nutrition in Humans Objective • describe the functions of main regions of the alimentary canal and the associated organs, namely mouth, oesophagus, stomach, small intestine, large intestine, liver, pancreas, gall bladder. Free Template from www.brainybetty.com 2 Nutrition 3 Nutrition • What is nutrition? • Nutrition is process of taking in food and converting it to living matter • Nutrition consist of the following process: »Feeding or ingestion »Digestion »Absorption »Assimilation 4 What is feeding or ingestion? • Feeding: • Food is taken into the body 5 What is digestion? • Digestion: • Large food molecules are broken down into smaller soluble molecules that can be absorbed into body cells 6 The mammalian digestive system • Parts of digestive system 1. 2. 3. 4. 5. 6. 7. 8. Mouth Oesophagus Stomach Small intestine Large intestine Liver (A) Gall bladder (B) Pancreas (C) 7 Breaking food down • Your body breaks down food two ways: – Mechanical Digestion – Involves the tearing, crushing and mashing of food. – Example: When you take a bite and chew it with your teeth or when your muscles of the stomach contract and relax. – Chemical Digestion – When chemicals called enzymes help break down food into nutrients. 8 Mouth Oesophagus Path of food (MOUTH) Stomach Small Intestine Large Intestine • Food enters body through mouth, which leads to buccal cavity. • Teeth: Breaks down large pieces of food into smaller pieces. Rectum/Anus • Salivary glands: secrete saliva into mouth • Tongue: helps mix food with saliva. 9 Mouth Oesophagus Path of food (Oesophagus) Stomach Small Intestine Large Intestine • The oesophagus is a muscular tube in the chest that connects the mouth and throat to the stomach. Rectum/Anus 10 Mouth Oesophagus Path of food (Stomach) Stomach Small Intestine Large Intestine • At stomach, food is churned and mixed with digestive juices (enzymes and acid) that breakdown food molecules, causing the mixture to becomes a thick liquid, with the consistency of a milkshake (chyme). Rectum/Anus 11 Mouth Oesophagus Path of food (Small intestine) Stomach Small Intestine Large Intestine Rectum/Anus • Digestion of fats, proteins and carbohydrates contained in the foods you consume, is completed within the small intestine. • The resulting nutrients produced are absorbed through the lining of the small intestine and transferred to the bloodstream. 12 Mouth Oesophagus Path of food (Large intestine) Stomach Small Intestine Large Intestine Rectum/Anus The large intestine performs the following functions: • reabsorbs water and maintains the fluid balance of the body • absorbs certain vitamins • stores waste before it is eliminated. 13 Organs associated with alimentary canal (Liver) • Liver performs many functions – Liver cells secrete bile – Bile is an alkaline greenish-yellow liquid containing bile salts and bile pigment – Bile salts speed up digestion of fats 14 Organs associated with alimentary canal (gall bladder) • Bile is stored in the gall bladder. • Gall bladder is a greenish-yellow bag attached to the liver. • When gall bladder contracts, bile flows into small intestine via bile duct 15 Organs associated with alimentary canal (pancreas) • Pancreas produced pancreatic juices which contains digestive enzymes. • Pancreas also secretes the hormone insulin and glucagon. Both hormones play an important role in controlling glucose concentration in blood. Free Template from www.brainybetty.com 16 Summary • describe the functions of main regions of the alimentary canal and the associated organs, namely mouth, oesophagus, stomach, small intestine, large intestine, liver, pancreas, gall bladder. 17