GCSE Biology (9-1) - The Digestive System

⭐️ Check out our website https://www.cognito.org/ ⭐️ *** WHAT'S COVERED *** 1. The two main roles of the digestive system: * Digestion: The breakdown of large food molecules (carbohydrates, proteins, lipids) into smaller, soluble molecules. * Absorption: The movement of these small molecules from the digestive tract into the bloodstream. 2. The journey of food through the digestive organs and their functions: * Mouth: Role of teeth and salivary glands (producing amylase). * Oesophagus (Gullet). * Stomach: Role of muscular walls, pepsin (protease enzyme), and hydrochloric acid. * Small Intestine: Where most digestion and absorption occurs, involving enzymes like carbohydrase, protease, and lipase. * Pancreas: Production of pancreatic juices containing digestive enzymes. * Liver and Gallbladder: Production of bile by the liver and its storage/release by the gallbladder to neutralise stomach acid and emulsify lipids. * Large Intestine: Absorption of excess water. * Rectum and Anus: Storage and egestion of faeces. 3. Adaptations of the small intestine for efficient absorption: * Large surface area due to villi and microvilli. * Thin walls (single layer of surface cells) for a short diffusion path. * Good blood supply to maintain a steep concentration gradient. *** CHAPTERS *** 0:00 Introduction 0:19 Role of the Digestive System 1:20 Organs of the Digestive System 1:51 Mouth 2:52 Oesophagus and Stomach 3:34 Small Intestine, Pancreas & Gallbladder 3:55 Pancreas Function 4:00 Gallbladder & Bile Function 5:14 Small Intestine Function 6:15 Adaptations of the Small Intestine 7:10 Large Intestine, Rectum & Anus *** PLAYLISTS *** https://youtube.com/playlist?list=PLidqqIGKox7XPh1QacLRiKto_UlnRIEVh&si=orIUwL3o2jOoiYjT https://youtube.com/playlist?list=PLidqqIGKox7X5UFT-expKIuR-i-BN3Q1g&si=DcihOwUkd9oWbbdp https://youtube.com/playlist?list=PLidqqIGKox7WeOKVGHxcd69kKqtwrKl8W&si=Y8MsO-FK948jnxpS https://youtube.com/playlist?list=PLidqqIGKox7UVC-8WC9djoeBzwxPeXph7&si=-7i5Iq7yOeJrhtu6 https://youtube.com/playlist?list=PLidqqIGKox7VKJD2WxRhoKaI6JGLVean8&si=NH_Q1ujhVgACM2FU #GCSE #Biology #study