The digestive system of amphibians is a simple gastric structure similar to that of other vertebrate animals. This system changes during the maturation of amphibians, being one way when they are aquatic larvae and another when they move in the air and on the ground.
Amphibians, also called batrachians, are animals that live between water and land. They are of moist skin, without scales or hair. They fulfill two stages in their life; one in the water in which their respiration is through gills and another out of the water in which they require lungs. Therefore, they need both means to develop fully.
Most amphibians go through a metamorphosis, or change in their body. They are born through eggs in the water as tadpoles and later reach their adult stage when their physiognomy allows them to come out in contact with air and land.
Despite this mixed nature, amphibians have a digestive structure of vertebrates and not fish. They have a mouth, esophagus, and stomach. Fish only have a small intestine, while amphibians have both a small and large intestine.
Structure of the digestive system of amphibians
1- In the larvae
In their terrestrial and aquatic forms the digestive system of amphibians mutates. The same goes for your eating habits.
The tadpoles or larvae feed on algae and the remains of dead organisms. But, once adults, they are carnivores, so they eat flies, spiders, and insects.
2- In adult amphibians
Anatomy of the frog. Right atrium. 1-Liver. 2-Aorta. 3- Egg dough. 4-Colon. 5-Left atrium. 6-Ventricle. 7-Stomach. 8-Left lung. 9-spleen. 10-Small intestine.
CloacaPicture taken by Jonathan McIntosh / CC BY (https://creativecommons.org/licenses/by/2.0)
The digestive system of the adult animal has several structures:
In larvae, the structure is simple, they have a mouth, an esophagus, a stomach as a store and an elongated intestine.
First of all, it has a long mouth as a way of entry for its food.
Their mouths do not have teeth but they do have a highly developed league, which is essential to begin the eating process. Some may have teeth but they are very small.
The tongue of amphibians has a viscosity that makes it very sticky. This allows the animal to capture its prey that are usually flying or standing in the environment.
Also, the tongue is protractile. This characteristic indicates that it can project out of the mouth covering a long distance.
Behind the mouth is the short and wide esophagus. This is the channel that connects to the stomach and through which food passes into the body.
The stomach, for its part, contains glands that produce digestive enzymes. These substances are capable of helping the decomposition and transformation of food into nutrients.
Furthermore, this extracellular cavity is where digestion itself begins.
The structure of the stomach has a valve before it and one after it that prevent food from returning or leaving the stomach down. The first is called the cardia and the second pylorus.
The stomach then connects to the small intestine, where nutrients are assimilated through absorption.
Meanwhile, the large intestine is where feces are produced, which are equivalent to waste that cannot be used by the amphibian's body. Here also a reabsorption of liquids occurs to dry the residual product.
Another peculiarity is that the intestine of amphibians does not end in an anus but in a "cloaca". This is a common widened opening of the excretory, urinary, and reproductive digestive systems.
In addition, it has attached glands, such as the liver and pancreas, which produce important secretions that aid in digestion.
References
- Digestive system. Editorial COA. Nutrition for far-sighted children. Recovered from coa-nutricion.com
- AsturnaturaDB. (2004 - 2017). Amphibians. Digestive system. Recovered from asturnatura.com
- Pilar, M. (2016). Digestive system. Animal Organs. Faculty of Biology. University of Vigo. Recovered from mmegias.webs.uvigo.es
- Digestive System of Amphibians. (2015). Recovered from es.scribd.com
- AMPHIBIAN DIGESTIVE SYSTEM. (2015). Recovered from zvert.fcien.edu.uy.