Understanding the Alimentary Canal
A baby frog, or a tadpole, feeds on plants such as algae and plankton. The adult frog, however, is a carnivore, eating mainly insects such as spiders, slugs, worms, or any other moving or living thing that will fit into its mouth.
For this reason, gardeners love frogs for their pest control abilities. Larger frogs can eat small animals such as rats, baby chickens or ducks. It is necessary to understand what an adult frog eats to be able to understand its digestive system, its organs, and why it works the way it does.
A frog's digestive system obviously begins with its mouth. Although frogs have two sets of teeth in the buccal cavity, they do not use them to eat their prey. These are used to hold the prey until it can be swallowed. The male frogs have a pharynx, which is in the throat on the way to the esophagus.
This is where the male vocal sacs are, and basically are openings of the eustachian tubes, connecting to the male's gullet and esophagus. Here is how it works:
- The tongue brings the food into the mouth, where the teeth hold the food if needed until the frog swallows its prey whole.
- Once the food is swallowed, or ingested, it passes through a very short esophagus to a much larger stomach.
- The stomach is a holding tank of sorts for the frog. However, very shortly after entering the stomach, the digestion process begins.
- When the food is digested enough, it enters a region called the pylorus. This is where the muscular pyloric valve works to send the food into the small intestine.
- The small intestine is a thin tube that consists of an area that is enlarged called the duodenum, which is joined to the stomach and the coiled ileum. It coils often, allowing for more absorption of food.
- When the dissolved food passes through the duodenum, it gets absorbed through the walls of the intestines into the bloodstream.
- Next, the small intestine dumps what is left into the short and stubby colon, or large intestine.
- From here, all of the remaining indigestible waste is pushed through the short, tubular cloaca, and then exits the body. Both liquid and solid wastes exit the body through the cloaca, as well as sperm and eggs during reproduction.