Digestive System MYP4 Biology and Geology PDF

Digestive system MYP4 – Biology and geology Digestive system Provide nutrients to the organism Nutrition: set of processes by which our body acquires, transforms and provides the cells with the nutrients they need to develop their vital processes Types of digestion Mechanical...

Digestive system MYP4 – Biology and geology Digestive system Provide nutrients to the organism Nutrition: set of processes by which our body acquires, transforms and provides the cells with the nutrients they need to develop their vital processes Types of digestion Mechanical digestion: physically breaking down food substances into smaller parts Chemical digestion: degradation of the molecular structure of food through digestive enzymes Gastrointestinal tract 3 main layers Mucous membrane: absorbs nutrients and protects the surface Muscular layer: allows the food to advance Peristaltic movements: sequential contraction of muscles to push the food forwards Nerves: direct the movement of food Gastrointestinal tract Mouth: Food < bolus Teeth: chew the food Tongue: muscle with taste buds Salivary glands – amylase enzyme breaks down starch into simple sugars Gastrointestinal tract Pharynx: Connects the mouth to the esophagus Epiglottis Esophagus: connects to the stomach Peristalsis Gastrointestinal tract Pharynx: Connects the mouth to the esophagus Epiglottis Esophagus: connects to the stomach Peristalsis Gastrointestinal tract Stomach: Bolus < Chyme Temporarily stores food Contracts and relaxes to mix and break down food Produces enzymes (protease) and digestive juices (HCl) to digest food Gastrointestinal tract Small intestine: Gastrointestinal tract Small intestine: Duodenum: chyme is mixed with secretions from the pancreas and gall bladder Gastrointestinal tract Small intestine: Duodenum: chyme is mixed with secretions from the pancreas and gall bladder Jejunum: absorption of nutrients Gastrointestinal tract Small intestine: Duodenum: chyme is mixed with secretions from the pancreas and gall bladder Jejunum: absorption of nutrients Ileum: finish absorption Gastrointestinal tract Large intestine: Absorption of water and minerals Excretes waste substances through the rectum Digestion and biomolecules Gland Enzyme Nutrient it breaks down Salivary glands Saliva (amylase) Starch → simpler carbohydrate Protease Proteins → Disassembled Gastric gland HCl proteins Pancreas Pancreatic juice (lipase) Lipids → Simpler lipids Liver and Simpler lipids → Fatty acids and Bile gallbladder glycerol Simpler carbohydrates → Maltase/Lactase/Sucrase Monomers Small intestine Protease Dissasembled proteins → Aminoacids Types of nutrients Organic nutrients: come from living beings Carbohydrates, lipids, proteins and vitamins Inorganic nutrients: minerals Other “non-nutrients”: water and fibre Organic nutrients Carbohydrates: most common source of energy for cells Simple carbohydrates: sugars (fruits, honey, sugar cane, etc.) Complex carbohydrates: starch (cereals, legumes, etc.) Lipids: provide energy long term Fats: stored as a reserve in the cells of the adipose tissue Saturated fats: have an animal origin contain cholesterol (eggs, milk, butter, etc.) Unsaturated fats: have a plant origin (avocados, olive oil, etc.) Proteins: contribute to the growth and regeneration of cells Can come from animals (meat, fish, milk) or plants (legumes) Vitamins: help cells regulate the different chemical reactions The body cannot make them, we have to consume them! Organic nutrients VITAMIN FUNCTION ORIGIN A It is important for growth Carrot, tomato, lettuce, egg, and vision. milk, etc. B It is important for growth, Milk, cheese, cereals, the nervous system and vegetables, meat, fish, etc. many other functions. C It is necessary for the Tomatoes, milk, oranges, absorption of iron. lemons, etc. D It is important for the bones. Milk, egg, butter, fatty fish, etc. E It is an antioxidant Vegetable oils, cereals, etc. component. K It is important for blood Cabbage, spinach, etc. Inorganic nutrients Minerals: part of the structure of the organism, help regulate the chemical reactions that take place in the cells Necessary “non-nutrients” Water: indispensable for the function of the human body Transport of substances by the organism Regulation of body temperature Support of chemical reactions in the cell Necessary “non-nutrients” Fiber: facilitate the process of digestion Cannot be digested