Deck 6

Question 1

Describe the mechanism of development of secretory diarrhoea in the presence of E. coli heat labile toxin

Answer 1

Heat labile toxin enters into adenyl cyclase-cyclic AMP system leading to the prod. of specific protein kinase, which blocks NaCl entry process on the absorptive cells & cause Cl- secretion in the crypt cells directly or by releasing of free Ca

Question 2

Give a definition of osmotic diarrhoea & describe mechanisms of osmotic diarrhoea in animals

Answer 2

Osmotic diarrhoea: is due to impaired particles absorption or intake of indigestible molecules, which causes osmotic flow of water into the lumen of the intestines due to increased osmotic pressure

MECHANISMS:

1. Osmotic diarrhoea in lactose deficiency: intake of lactose, where lactose is not digested leads to lactose remaining in the intestines. This causes water to be drawn into intestines -> increased vol.of intestine & frequency of defecation
2. Osmotic diarrhoea in calves & lambs induced by non-milk carbohydrates: excessive feeding of non-milk carbs. increases their fermentation in the colon -> increased prod. of lactic acid -> causes water to be into the intestines -> increased vol. of intestine & frequency of diarrhoea
3. Osmotic mediated diarrhoea caused by drugs: use of osmotic laxatives/ antacid drugs w/poor intestinal absorption, causing water to be drawn into intestines -> increased vol. of intestine & frequency of defecation

Question 3

Name 3 consequences of malabsorption & explain their mechanisms

Answer 3

Malabsorption -> is the problem of inadequate
absorption of nutrients. Can be
generalised or specific to a particular
nutrient

Consequences:
- Vit. B12 deficiency -> leads to anaemia
- Lack of vit. K -> coagulation disorders
- Defective digestion & absorption of fats by intestine ->
steatorrhea
- Inadequate water absorption -> diarrhoea

Question 4

Lactose - mechanism in diarrhoea

Answer 4

Osmotic diarrhoea in lactose deficiency -> intake of lactose where lactose is not digested -> lactose remaining in intestines causing water to be drawn into intestines -> increased volume of intestine & frequency of defecation

Question 5

Pathological mechanism of steatorrhea

Answer 5

1. Cholestasis (failure to secrete bile) -> causes failure to
   soubise fats -> causing steatorrhea
2. Deficiency of pancreatic lipase -> causes steatorrhea
3. Bile salt deficiency -> steatorrhea