the digestive stystem

• What is the main focus of this unit?

  How organ systems work together
• What does the digestive system do?

  It digests and absorbs nutrients
• What is the role of the respiratory system?

  It absorbs oxygen from the air
• What does the circulatory system do?

  Moves essential substances around the body
• What can damage to organ systems lead to?

  Serious and fatal conditions
• How can people reduce their risk of serious health issues?

  By improving diet and lifestyle
• What are the three methods of substance movement in cells?

  • Diffusion
  • Osmosis
  • Active transport
• What is diffusion?

  Movement from high to low concentration
• What is osmosis?

  Movement of water from high to low concentration
• What is active transport?

  Movement from low to high concentration using energy
• What features support substance movement in cells?

  Highly folded membranes, thin walls, good blood supply
• Why do cells need lots of mitochondria for active transport?

  To provide energy from respiration
• What are cells?

  Building blocks of all living organisms
• What is a tissue?

  A group of similar cells
• What is an organ?

  A group of different tissues
• What is an organ system?

  A group of organs working together
• What does the digestive system do with food molecules?

  Breaks down large insoluble molecules
• Where are enzymes produced?

  In the small intestine and pancreas
• What is the lock and key theory in relation to enzymes?

  The active site fits the substrate's shape
• Name a type of carbohydrase.

  Amylase
• What does protease do?

  Breaks down protein into amino acids
• What is pepsin?

  A type of protease found in the stomach
• What does lipase do?

  Breaks down lipids into fatty acids and glycerol
• Where is amylase produced?

  In the small intestine and salivary glands
• What is the function of the mouth in digestion?

  Begins the process of digestion
• What are the two types of digestion?

  Mechanical and chemical digestion
• What is mechanical digestion?

  Physical action of teeth and stomach
• What is chemical digestion?

  Breakdown by enzymes in digestive organs
• What do enzymes do?

  Speed up reactions without being used up
• What is the role of hydrochloric acid in the stomach?

  Kills bacteria and provides optimum pH
• Where is bile made?

  In the liver
• What does bile do?

  Emulsifies fats and increases surface area
• What is the pH of the stomach?

  Very acidic, around pH 2
• How does bile affect the pH of food from the stomach?

  Neutralizes acidic food from the stomach
• What is the result of emulsification by bile?

  Increases surface area for lipase action
• What does lipase do to fat molecules?

  Breaks them into glycerol and fatty acids
• What is the relationship between bile and lipase?

  Bile increases surface area for lipase to work
• What is the function of the gallbladder?

  Stores bile made in the liver
• What happens to large food molecules during digestion?

  They are broken down into smaller, soluble molecules
• Why do we need to digest food?

  To turn large molecules into smaller ones