Organisation and Digestive system

• Cells


  Basic unit of life
• Tissues


  Groups of similar cells performing a specific function
• Tissues


  • Muscle tissue
  • Nervous tissue
• Organs


  Structures made of different tissues working together for a specific function
• Organs


  • Heart
  • Lungs
  • Stomach
• Organ Systems


  Groups of organs that work together to perform complex functions
• Organ Systems


  • Digestive system
  • Circulatory system
• Mouth


  Part of the digestive system
• Teeth


  • Mechanically break down food
• Salivary Glands


  Produce saliva containing amylase, which begins the breakdown of starch
• Esophagus


  Transports food to the stomach via peristalsis (wave-like muscle contractions)
• Stomach


  Part of the digestive system
• Gastric Juice


  • Contains hydrochloric acid and pepsin, which start protein digestion
• Churning


  Mechanical digestion to mix food with digestive juices, turning it into chyme
• Small Intestine


  Part of the digestive system
• Duodenum


  First part of the small intestine; receives bile from the liver and digestive enzymes from the pancreas
• Jejunum and Ileum


  Absorb nutrients through villi and microvilli, which increase surface area for absorption
• Large Intestine


  Part of the digestive system
• Large Intestine


  • Absorbs water and salts from the remaining indigestible food
  • Forms and stores feces
• Rectum


  Stores feces until expulsion
• Anus


  Expels feces from the body
• Amylase


  • Produced in salivary glands and pancreas
  • Breaks down starch into simple sugars (maltose)
• Protease


  • Produced in the stomach (pepsin), pancreas, and small intestine
  • Breaks down proteins into amino acids
• Lipase


  • Produced in the pancreas and small intestine
  • Breaks down fats into fatty acids and glycerol
• Villi


  Finger-like projections that increase the surface area for absorption
• Microvilli


  Tiny projections on villi that further increase surface area
• Capillaries


  Absorb amino acids and simple sugars into the bloodstream
• Lacteals


  Absorb fatty acids and glycerol into the lymphatic system
• Large Intestine


  • Absorbs water, forming solid feces
  • Houses beneficial bacteria that produce vitamins (e.g., vitamin K)
• The digestive system breaks down food into nutrients that the body can use for energy, growth, and repair
• Enzymes play a key role in breaking down different types of food: amylase for carbohydrates, protease for proteins, and lipase for fats
• Absorption primarily occurs in the small intestine through structures called villi and microvilli, which maximize nutrient uptake
• The large intestine absorbs water and forms feces, completing the digestive process