The large intestine

• how long is the large intestine?

  1.5 metres long
• what does the large intestine comprise?

  • the caecum
  • the appendix
  • the colon
  • the rectum
• what passes into the colon?

  • undigested food
  • mucus
  • bacteria
  • dead cells
• what are the characteristics of the villi on the colon wall?

  • the colon wall has fewer villi than the ileum
  • these villi have a major role in water absorption
• where are vitamin K and folic acid secreted from?

  they are secreted by mutualistic (beneficial to both organisms involved) microorganisms living in the colon
• where are minerals absorbed from?

  from the colon
• what happens as material passes along the colon?

  • as material passes, water is absorbed, and by the time it reaches the rectum, the material is semi-solid
  • it passes along the rectum and is egested as faeces, in a process called defecation
• what happens when minerals reach the rectum?

  • by the time it reaches the rectum, the material is semi-solid
  • it passes along the rectum and is egested as faeces, in a process called defecation
• what are the layers of the colon wall?

  • mucosa (has larger villi than small intestine)
  • submucosa
  • circular muscle
  • longitudinal muscle
  • serosa
• what is defecation?

  the process by which undigested food waste is removed from the body, typically through the rectum and anus - its also known as egestion