The digestion (breakdown of food into materials an animal can use for energy) process of sharks is similar to our own, with many digestive organs being present in multiple animal groups.
HOWEVER, SHARK DIETS VARY AND THE FORM AND FUNCTION OF DIGESTIVE ORGANS ADJUSTS ACCORDINGLY. SHARK AND MOST ANIMAL DIGESTIVE SYSTEMS WORK HARDER THAN OURS AS FOOD ISN’T ALWAYS READILY AVAILABLE.
special adaptations: filter feeding sharks - like whale sharks!- have filter pads that strain plankton from the water, then funnel the small food down their throats.
#finfactL whale sharks create suction - they don't just swim forward with their mouths open!
the way food travels...
After leaving the mouth food travels through the pharynx, a membrane-lined cavity that pushes food into the esophagus. In many shark species the pharynx will also push water to the gills. From the esophagus food travels to the stomach.
Sphincters (rings of muscles) help move the food throughout different organs.
Stomach. A shark’s stomach is u-shaped and filled with rugae that help keep food moving along, plus acid to aid in digestion and mucus to protect the stomach lining. Shark tum tums generally make up 20% of the sharks body length and this is where a majority of digestion occurs.
Under high stress situations some shark species can vomit eject stomach contents, just like humans and vultures. Many can also eject their whole stomach out of their mouth, referred to as gastric eversion. A handful of species can even fully eject their stomachs! The stomachs then retract back into the body, causing no harm to the animal (besides the stress of the situation that caused it).
Intestine, filled with spiral valves to absorb as many nutrients and possible. Intestine broken into duodenum and ileum, both secrete enzymes for food breakdown and have surface area for nutrient absorption. Towards end of large intestine feces starts to be formed.
Cloaca: a common cavity at the end of the digestive tract for the release of both excretory and genital products. Cloaca is latin for “sewer” all things exit the cloaca
Liver works as a nutrient store AND unlike in humans aids in buoyancy. This is due to the oil found in the liver. A simple science experiment of mixing oil and water will help you understand the liver’s secondary function. Oil sits on top of water, therefore sharks that spend more time swimming at the surface tend to have larger, oiler livers. Shark liver oil is often collected and used in medicine as well. People take fish oil to help with eye issues, cancer and skin conditions (many other drugs are available and synthesized so no animals need to be harmed.
Spleen filters blood, aids immune system. Sharks do have strong immune systems, but it is false that they never get cancer.
Kidneys provides salt and water balance, important in animals living in salt water. Most water that ocean animals intake comes from their prey items.
Pancreas - protein breakdown, secretes digestive enzymes.
Gallbladder - stores bile.