digestive system

• What is the purpose of this video according to the narrator?

  To give an overview of the digestive system
• Why do humans need to eat food?

  For energy to move and keep metabolism running
• What are the three main groups of nutrients humans need?

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

  To break down food into absorbable tiny pieces
• What two processes does digestion rely on?

  Physical and chemical breakdown
• Where does digestion begin in the body?

  In the mouth
• What enzyme is present in saliva?

  Salivary amylase
• What is the role of salivary amylase?

  To break down carbohydrates
• What is the alternative name for the gullet?

  Esophagus
• What are three important features of the stomach?

  • Contracts to mix food
  • Produces pepsin
  • Produces hydrochloric acid
• What type of enzyme is pepsin?

  Protease
• What is the role of hydrochloric acid in the stomach?

  Kills bacteria and aids pepsin function
• Where does food go after leaving the stomach?

  The small intestine
• Where does the majority of digested food get absorbed into the bloodstream?

  The small intestine
• Which organ produces most of the digestive enzymes?

  The pancreas
• What form are the digestive enzymes pushed into the small intestine in?

  Pancreatic juices
• What does the gallbladder secrete into the small intestine?

  Bile
• What are the two main roles of bile?

  • Neutralizes stomach acid
  • Emulsifies fats
• Why is bile alkaline?

  To neutralize stomach acid
• What does emulsifying fats achieve?

  Increases surface area for enzymes
• Where is bile made?

  In the liver
• Where is bile stored?

  In the gallbladder
• How are nutrients absorbed in the small intestine?

  Across the lining into the bloodstream
• What are the finger-like projections in the small intestine called?

  Villi
• How do villi aid absorption?

  Increase surface area
• How many layers of surface cells do villi have?

  A single layer
• What does a single layer of surface cells in villi achieve?

  Shortens diffusion distance
• How does a good blood supply aid absorption?

  Maintains the concentration gradient
• What happens to undigested material in the small intestine?

  It passes into the large intestine
• What is absorbed in the large intestine?

  Excess water
• Where are feces stored before removal?

  In the rectum
• What will the next video in the series focus on?

  Enzymes used in digestion
• How does the stomach aid in the digestion process?

  By contracting its muscular walls