Biology paper 1

• Levels of organisation


  • Cells
  • Tissues
  • Organs
  • Organ systems
  • Organisms
• Stomach


  Part of the human digestive system
• Tissues in the stomach

  • Muscle tissue
  • Glandular tissue
  • Epithelial tissue
• Muscle tissue


  • Churns food
• Glandular tissue


  Produces digestive juices
• Epithelial tissue


  Covers inside and outside of stomach
• Human digestive system


  1. Mouth: breaks down food, salivary glands

  2. Oesophagus: muscle pushes food down (peristalsis)

  3. Stomach: hydrochloric acid produced, protease breaks down protein

  4. Duodenum: connects stomach and small intestine

  5. Small intestine: microvilli and villi increase surface area to absorb small particles

  6. Large intestine: absorb water

  7. Rectum: where faeces come out
• Enzymes


  Biological catalysts that speed up processes without being consumed
• Digestive enzymes


  Convert food into small soluble molecules that can be absorbed into the blood