The digestive system

• What are the two main roles of the digestive system?

  Digestion and absorption
• What is digestion?

  Breaking down large food molecules into smaller ones
• What happens to carbohydrates during digestion?

  They are broken down into glucose
• What is absorption in the digestive system?

  Absorbing small molecules into the bloodstream
• What do we absorb from the digestive tract?

  Small molecules, vitamins, minerals, and water
• How does food travel through the digestive system?

  It passes through tubes and organs
• What are the two important organs in the mouth?

  Teeth and salivary glands
• What is the role of the teeth in digestion?

  To physically break down food by chewing
• What do salivary glands release?

  Saliva containing the enzyme amylase
• What does amylase do?

  Breaks down starch into maltose
• What are enzymes like amylase called?

  Biological catalysts
• What is the muscular tube that food passes down?

  Esophagus
• What are the three important functions of the stomach?

  Mixing food, producing pepsin, and hydrochloric acid
• What does pepsin do?

  Breaks proteins down into amino acids
• What is the role of hydrochloric acid in the stomach?

  Kills bacteria and provides pH for pepsin
• What happens to the food mixture after the stomach?

  It moves into the small intestine
• What do the pancreas and gallbladder release into the small intestine?

  Pancreatic juices and bile
• What is the role of pancreatic juice?

  Contains digestive enzymes for food digestion
• What are the two roles of bile?

  Neutralizes stomach acid and emulsifies lipids
• Why is bile alkaline?

  To neutralize the acid from the stomach
• What does emulsifying lipids do?

  Breaks fat into tiny droplets for digestion
• Where is bile made?

  Liver
• What is the most important part of the digestive system?

  The small intestine
• What happens in the small intestine?

  Most digestion and nutrient absorption occurs
• What does the small intestine release to aid digestion?

  Digestive enzymes like carbohydrases and lipases
• What are villi?

  Tiny finger-like projections in the small intestine
• What are the important features of villi?

  Large surface area, single cell layer, good blood supply
• What do microvilli do?

  Further increase the surface area for absorption
• What happens to undigested material in the small intestine?

  It passes into the large intestine
• What is the role of the large intestine?

  To absorb excess water from undigested material
• What is the dry mixture left after water absorption called?

  Feces
• Where are feces stored before excretion?

  In the rectum
• How are feces removed from the body?

  Through the anus
• What is the journey of food through the digestive system?

  • Starts at the mouth
  • Passes down the esophagus
  • Enters the stomach
  • Moves into the small intestine
  • Passes into the large intestine
  • Excreted through the anus
• What are the key organs involved in digestion and their roles?

  • Mouth: Teeth break down food; salivary glands release amylase
  • Stomach: Mixes food, produces pepsin and hydrochloric acid
  • Pancreas: Releases digestive enzymes
  • Gallbladder: Releases bile
  • Small intestine: Digests food and absorbs nutrients
  • Large intestine: Absorbs excess water and stores feces
• What are the functions of digestive enzymes?

  • Break down carbohydrates into sugars
  • Break down proteins into amino acids
  • Break down fats into fatty acids
• What is the significance of the surface area in the small intestine?

  • Villi and microvilli increase surface area
  • Enhances absorption of nutrients
  • Allows for efficient diffusion
• What happens to nutrients after absorption in the small intestine?

  • Nutrients enter the bloodstream
  • Transported to cells for energy or rebuilding
• What is the role of the rectum in the digestive system?

  • Stores feces until excretion
  • Allows for controlled removal of waste