2.4 Structure of the mammalian gut

Question 1

name the 4 main tissue layers of the mammalian gut (outer to inner)

Answer 1

1. serosa
2. muscularis externa
3. submucosa
4. mucosa

Question 2

what are the 2 parts of the muscularis externa

Answer 2

1. longitudinal muscle
2. circular muscle

Question 3

what is the serosa

Answer 3

• outermost layer of tough connective tissue
• its function is protection and friction reduction.

Question 4

what is the longitudinal muscle

Answer 4

when it contracts, the gut gets shorter

Question 5

what is the inner circular muscle

Answer 5

when it contracts, the gut gets narrower

Question 6

what is the function of the muscularis externa as a whole

Answer 6

contractions cause peristalsis, which propels food along the gut.

Question 7

what is the submucosa

Answer 7

• consists of connective tissue, containing blood vessels(capillaries)
  Vessels transport absorbed digested molecules away from the gut.

contains nerves which coordinate muscular contractions(peristalsis)

Question 8

what is the mucosa

Answer 8

The mucosa secretes mucus from specialised cells (goblet cells)
mucosa secretes digestive juices

Question 9

what are the specialised cells which secrete mucus

Answer 9

goblet cells

Question 10

what is the reason for mucus

Answer 10

lubricates the mucosa, for protection from digestive juices