Digestive system

• What is the main function of the digestive system?

  To break down food for absorption
• What are the three main groups of nutrients humans need?

  Carbohydrates, proteins, and fats
• Why is digestion necessary for humans?

  To break down large molecules for absorption
• What is the role of saliva in digestion?

  To make food more liquid and aid breakdown
• What enzyme is found in saliva and what does it do?

  Salivary amylase breaks down carbohydrates
• What is the esophagus also known as?

  The gullet
• What are the three important functions of the stomach?

  Mix food, produce pepsin, and hydrochloric acid
• What type of enzyme is pepsin?

  A protease enzyme
• What is the role of hydrochloric acid in the stomach?

  Kills bacteria and activates pepsin
• What happens to food after it leaves the stomach?

  It enters the small intestine
• What is the primary function of the small intestine?

  To absorb digested food into the bloodstream
• Which organ produces most of the digestive enzymes?

  The pancreas
• What is the role of bile in digestion?

  Neutralizes stomach acid and emulsifies fats
• Where is bile produced?

  In the liver
• What is the function of villi in the small intestine?

  To increase surface area for absorption
• How do the adaptations of villi aid in nutrient absorption?

  They have a large surface area and good blood supply
• What happens to undigested material in the large intestine?

  Excess water is absorbed, forming feces
• Describe the process of digestion from start to finish.

  1. Food is chewed in the mouth.
  2. Saliva is added, containing salivary amylase.
  3. Food travels down the esophagus to the stomach.
  4. Stomach mixes food, producing pepsin and hydrochloric acid.
  5. Food moves to the small intestine with pancreatic juices and bile.
  6. Nutrients are absorbed into the bloodstream.
  7. Undigested material goes to the large intestine.
  8. Water is absorbed, leaving feces in the rectum.
• What is stored in the rectum?

  Feces
• What is the pH of bile and why is it important?

  Bile is alkaline, neutralizing stomach acid
• How does the digestive process change the state of food?

  It breaks food into smaller absorbable pieces