Gut wall structure

• Label this diagram of the gut wall structure

  A) submucosa

  B) circular muscle

  C) longitudinal muscle

  D) serosa

  E) mucosa

  F) lumen

  
• Label this diagram

  A) lumen

  B) mucosa

  C) sub-mucosa

  D) inner circular

  E) outer longitudinal

  F) muscle layer

  G) serosa

  
• What tissues are present in the mucosa and what are their functions?

  -epithelium: lines the gut and can be adapted for absorption, e.g. villi

  -goblet cells: secretes mucus, lubricates passage of food (reduces friction), and prevents autodigestion (where enzymes and acids digest cells of the gut)
• What does the sub-mucosa contain and what are their functions?

  -capillaries: brings blood containing oxygen/glucose to supply cells of mucosa, transports absorbed nutrients (maintains concentration gradient)

  -nerve fibres: coordinates contractions of the muscle layer for peristalsis

  Both of these are types of connective tissue
• What types of muscle does the muscle layer contain?

  -inner circular muscle

  -outer longitudinal muscle
• What is the function of the muscle layer?

  Responsible for peristalsis (waves of muscular contraction that moves food through the gut)

  -in some places, muscle is thickened to form sphincters (controls the movement of food through the gut)
• What is the serosa?

  -outermost layer of the gut

  -made of tough connective tissue

  -protects the gut from friction with other organs