Large intestine structure and function

Question 1

How long is the large intestine?

Answer 1

1.5 - 1.8m

Question 2

What causes the pouches rather than the full constrictions in the large intestine when compared to the small intestine?

Answer 2

Circular muscle layer complete but longitudinal muscle layer incomplete

Question 3

How can we tell between the large and small intestine?

Answer 3

Haustra
Tenia coli
Omental appendages

Question 4

What is the main function of the large colon?

Answer 4

Dehydration of chyme by active transport of sodium into blood (causes osmotic force)

Question 5

Quantify colonic microbiota

Answer 5

Colonic microflora = 1014 bacteria (~1Kg)

Question 6

What is produced following bacterial fermentation of carbohydrates?

Answer 6

==> Short chain fatty acids (energy source in ruminants)
==> Vitamin K (blood clotting)
==> Gas (flatus) - nitrogen, CO2, hydrogen, methane, hydrogen sulphide

Question 7

Give some examples of enterotoxigenic bacteria

Answer 7

Vibrio cholerae

Escherichia coli

Question 8

What are enterotoxigenic bacteria

Answer 8

Produce protein enterotoxins which maximally turn on intestinal chloride secretion from crypt cells to massively increase water excretion, causing severe secretory diarrhoea

Question 9

How do you treat secretory diarrhoea?

Answer 9

Give sodium/glucose solution to cause water reabsorption and reduce diarrhoea
Also give oral rehydration solution