Digestive System SAQs.docx

The Human Digestive System SAQs - Define Nutrition. 1. Nutrition is the way in which an organism obtains its food.  - What is the difference between autotrophic and heterotrophic nutrition?  1. Autotrophic organisms can make their own food while heterotrophic organisms can't make...

The Human Digestive System SAQs - Define Nutrition. 1. Nutrition is the way in which an organism obtains its food.  - What is the difference between autotrophic and heterotrophic nutrition?  1. Autotrophic organisms can make their own food while heterotrophic organisms can't make their own food and eat other organisms.  - What is another name for the alimentary canal?  1. the gut  - Name 3 functions of food.  1. Energy source/ Material for growth and repair of cells/ Replacement of cells/ Reproduction (growth of foetus)/ Defence   - What are the 5 stages of human nutrition?  1. ingestion, digestion, absorption, assimilation, egestion.  - What is physical digestion?  1. Physical digestion is the breakdown of food from a large substance to a smaller substance**. ** - Where does physical digestion take place?  1. the mouth, stomach and oesophagus.  - What is chemical digestion?  1. The breakdown of food into simpler nutrients using enzymes and acid.  - Where does chemical digestion take place?  1. the mouth, stomach and duodenum.  - State the human dental formula.  1.  I 2/2, C 1/1, PM 2/2, M 3/3  - What enzyme present in the mouth breaks down starch to maltose?  1. amylase  - What is the mouth's pH?  1. 7-8 pH  - Define Peristalsis.  1. The alternate contraction and relaxation of the muscles of the alimentary canal that push food along.  - What type of muscle is present along the alimentary canal?  1. involuntary muscle.  - What stimulates peristalsis?  1. fibre  - What is food known as when it leaves the mouth?  1. Bolus  - What is the pH of the stomach?  1. 2-3 pH  - What is the epiglottis?  1. a flap of skin covering the trachea when we swallow to prevent food entering our lungs.  - What is gastric juice made up of?  1. Hydrochloric acid, pepsinogen and mucous.  - What is the function of Hydrochloric acid in the stomach?  1. To kill germs and activate pepsin  - What is the function of mucous in the stomach?  1. To protect against hydrochloric acid damage and self digestion by pepsin.  - Physical digestion in the stomach occurs when the stomach churns food into a liquid. Name this liquid.  1. Chyme.  - What are the 2 parts of the small intestine?  1. the ileum and the duodenum  - Where in the small intestine does digestion occur?  1. the duodenum  - Name 2 adaptations of the ileum that aid in the absorption of nutrients.  1. It is very long to allow time for maximum absorption/ Has villi and microvilli which increase the surface area for absorption/ It has lots of capillaries to allow for maximum absorption into the bloodstream.  - Give 1 function of the pancreas  1. to produce the hormone insulin/ produces a range of digestive enzymes  - Give 2 functions of the liver  1. produce bile, break down old blood cells, store fat soluble vitamins and glycogen, make cholesterol (needed to make many hormones) and the deamination of proteins that are no longer required**. ** - Where is bile stored? 1. the gallbladder ** ** - What is the function of bile?  1. It emulsifies fats and neutralises acid in the stomach.  - List the 5 parts of the large intestine  1. colon, caecum, appendix, rectum, anus.  - In which part of the large intestine is faeces stored?  1. the rectum  - What are the functions of the large intestine?  1. to reabsorb water and absorb B group vitamins.  - Name a disorder of the digestive system and its symptoms  1. disorder = stomach ulcers  symptoms =  a burning pain in the centre of the abdomen.