Digestion of the Sharks

by Brian Osborne

1. Sharks always either shallow their food whole or in large chunks.  Sharks need to consume about 0.5 to 3% of their body weight a day.  

2. Most sharks have U-shaped stomachs with strong acids to dissolve most everything they consume.  

3. Sharks have folds in the stomach called rugae which are used in digestion.  They  allow the stomach to greatly expand.

4. The stomach produces a soup-like mush which passes through the pyloric valve into the intestines.

5. The liver produces bile to aid in digestion.  The liver can weigh up to a quarter of the shark's total mass.

6. Shark throw up everything else including bones

7. Intestines are short, but since they lined with spiral valves that increase the surface area, all of the nutrients are absorbed in here.

8. After digestion, the waste is released through the cloaca.

9. The rectal gland secretes excess salts that have been consumed into the cloaca.

 

 

Number 5 is the stomach and on the inside are the rugae. Number 1 is the intestine.

 

Number 3 in this photograph is the spiral valves in the intestine used to increase surface area for digestion of its food.

Photographs by R.M. Deeley, http://www.sciencebugz.com