Digestive System PDF

# Digestive system/digestion: The process of digesting food. ## 2 types of Digestive system - Large food molecules to small, soluble and disffusible molecules that can be absorbed by the cells in the body. - Digestion process where they are broken down. ### Involves - **Physical Digestion** - B...

# Digestive system/digestion: The process of digesting food. ## 2 types of Digestive system - Large food molecules to small, soluble and disffusible molecules that can be absorbed by the cells in the body. - Digestion process where they are broken down. ### Involves - **Physical Digestion** - Breaking down food into small particles by chewing or mechanically churning. - **Chemical Digestion** - Involves breaking down food into small particles by digesting enzymes. ## Human Digestive system ### 1. Mouth/teeth/tongue - **Teeth:** soften food, increase surface area and begin mechanical breakdown of food by chewing. - **Mouth/tongue:** lubricate food, form food into a ball (bolus) with saliva. - **Amylase:** an enzyme found in saliva, begins chemical digestion of starches. - **Saliva:** creates the bolus, ready for swallowing. ### 2. Epiglottis - A muscular flap that prevents food from entering the airway (trachea) during swallowing. - Trachea is covered up, no food can enter. - Epiglottis moves downwards. ### 3. Oesophagus - Enables food (bolus) to be transported down to the stomach. - Muscular contractions (peristalsis) that are involuntarily. ### 4. Stomach - Digestion in the stomach breaks down food into digestible parts. - Stomach is a muscular bag, can churn the food. - Enzymes present are gastric juice proteases and hydrochloric acid. - Hydrochloric acid helps to kill bacteria. - Food stays for 2-6 hrs. - Ends up as partially digested food - chyme. ### 5. Small intestine - Absorbs nutrients. - Small intestine has finger-like projections (villus) to increase surface area. - Villus increases surface area for absorption of carbs, protein and fat. - Enzymes present are carbohydrate, protein and fat enzymes. - Bile is produced by the liver, stored in the gall bladder, secreted into the small intestine. - The small intestine absorbs water. ### 6. Large intestine - Food reaches the large intestine by passing through the small intestine. - The body absorbs water by passing through the large intestine. - Faeces is stored in the rectum. ### 7. Rectum - A chamber that: - Receives faeces from the long intestine. - Lets the faeces get stored temporarily in the rectum. - Holds the faeces until there is a need for evacuation. ### 8. Anus - Connects the rectum with the outside to be evacuated (pooped out). - Controls the release of stool until voluntarily released ("pooped out"). - We rely on pelvic floor muscles to hold in the stool. - When we have to poo, these muscles can relax and we poo. ## Ancillary Organs ### Salivary Glands - 1. Parotid glands are found in front of the ear. - 2. Submandibular glands are below the jaw. - 3. Sublingual glands are under the tongue. ### Gall bladder - A small pear-shaped organ located on the right side & beneath your liver. - Stores bile which is produced by the liver. ### Liver - A critical organ in the human body, responsible for an array of function that support metabolism, immunity, digestion, and detoxification. - Storage of vitamins. ### Pancreas - An organ of digestive and endocrine system. - The pancreas produces enzymes that help the body digest food, mainly proteins. - The pancreas makes the hormone insulin. Insulin helps control blood sugar levels. ## Enzyme - A protein, or a substance that is produced for a specific biochemical reaction. - An Enzyme helps speed up metabolism, the chemical reactions in our body. - Digestive Enzymes - Carbohydrase to digest carbohydrates. - Protease to digest proteins. - Lipase to digest fats (lipids). The image shows an illustration of the human digestive system, with different organs highlighted and labelled. It also includes descriptions of the various digestive processes and the role of enzymes in digestion.