12535322
Description
Flashcards by Mrs Z Rourke, updated more than 1 year ago
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Created by Mrs Z Rourke
over 6 years ago
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| Question | Answer |
| Describe the pathway for air into the lungs. | 1. Through the nasal cavity or mouth 2. Down the trachea 3. Splits at the bronchi 4. Into the bronchioles 5. Into the alveoli where gas exchange will occur |
| Describe the process of inspiration (inhaling). | Diaphragm contracts and flattens. Intercostal muscles contract causing ribs to expand. Volume inside chest increases. Pressure inside chest decreases. Air moves in. |
| Describe the process of expiration (exhaling). | Diaphragm relaxes and moves up. Intercostal muscles relax causing ribs to move in and down. Volume inside chest decreases. Pressure inside chest increases. Air forced out. |
| What is the composition of gases in inhaled air? | 79% Nitrogen 21% Oxygen 0.04% Carbon dioxide |
| What is the composition of gases in exhaled air? | 79% Nitrogen 16% Oxygen 4% Carbon dioxide |
| Why is digestion needed? | To breakdown large molecules into smaller molecules so they can be absorbed for use by body cells |
| What is an enzyme? | Biological catalyst - speeds up the rate of a chemical reaction |
| Describe the function of enzymes' action (lock and key hypothesis). | |
| What 3 factors affect enzyme activity? | Temperature pH Substrate concentration |
| What does optimum temperature mean? | The temperature an enzyme works best at. |
| What does optimum pH mean? | The pH an enzyme works best at. |
| What enzyme breaks down fats? | Lipase |
| What are fats broken down into? | Fatty acids and glycerol |
| What enzyme breaks down proteins? | Protease |
| What are proteins broken down into? | Amino acids |
| What enzyme breaks down carbohydrates? | Carbohydrase |
| What are carbohydrates broken down into? | Simple sugars |
| What enzyme breaks down starch? | Amylase |
| What is starch broken down into? | Glucose |
| How would you test for the presence of starch? | Use iodine - it would turn from a brown to blue/black colour |
| How would you test for the presence of glucose? | Benedict's reagent and heat - it would turn from a blue colour to brick red |
| How would you test for the presence of protein? | Biuret solution - will change from blue to violet |
| Label the parts of the digestive system. | 1. Mouth 2. Oesophagus 3. Stomach 4.Small intestine 5. Pancreas 6. Large intestine 7. Anus 8. Liver 9. Gall bladder |
| What is the role of the mouth? | Digestion starts here - teeth break down food into smaller pieces. This increases surface area for amylase to start breaking down starch. Saliva contains amylase and lubricates the food bolus. |
| What is the role of the stomach? | Contains protease to break down proteins. Also contains hydrochloric acid to aid digestion and kill microbes. |
| What is the role of the pancreas? | Secretes lipase, proteases and carbohydrases into the small intestine |
| What is the role of the small intestine? | Digests carbohydrates, proteins and fats. The digested molecules are absorbed across the villi of the small intestine. |
| What is the role of the large intestine? | Water is absorbed out of the remaining food to leave behind faeces. |
| What is the role of the liver? | Secretes bile (which is stored in the gall bladder and secreted into the small intestine when required) |
| Why is bile required? | 1. Bile emulsifies fat into smaller fat droplets. This increases the surface area for lipase to digest the fat. 2. Bile increases the pH in the small intestine to the optimum pH for enzyme acitivity. |
| How is food moved along the alimentary canal (through the digestive system)? | Peristalsis - muscles contract above the food bolus to push the food along |
| How is the small intestine adapted to absorb soluble subtances into the blood stream? | 1. Villi increase the surface area 2. Rich blood supply - maintains a concentration gradient |
| How does the body use fatty acids and glycerol? | For energy |
| How does the body use glucose? | For energy |
| How does the body use amino acids? | To build proteins in the body |
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