Amphibians - PowerPoint PPT Presentation

Who can edit:

Liver is very large and consists of five lobes. The food travels through the digestive tract, beginning at the mouth and goes through the esophagus, stomach and intestines. On both jaws teet are present, polyphyodont homodont teeth arranged in a single row on each jaw. Unicellular mucous glands are absent in the epithelium of bucco-pharyngeal region. From Stevens and Hume Here also occurs a reabsorption of liquids to dry the residual product. The same is true of your eating habits.


How is the Amphibian Digestive System?

Their mouths do not have teeth but they do count on a very developed tongue, fundamental to begin the alimentary process. Some may have teeth but are very small.

The tongue of the amphibians is provided with a viscosity that makes it very sticky. This allows the animal to catch its prey that are usually flying or standing in the environment.

In addition, the tongue is protractile. This feature indicates that it can project out of the mouth covering a long distance. After 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, on the other hand, contains glands that produce the digestive enzymes. These substances are able to aid in the decomposition and transformation of food into nutrients.

The structure of the stomach has a valve before it and one after that prevent food from being returned or leaving the stomach down. The first is called cardias and the second pylorus. The stomach is then connected with the small intestine, in which the assimilation of the nutrients takes place through absorption.

Moreover, the large intestine is where feces occur, which are equivalent to waste that can not be used by the amphibian organism. Here also occurs a reabsorption of liquids to dry the residual product. Another peculiarity is that the intestine of the amphibians does not end in an anus but in a"cloaca".

This is a common enlarged opening of the digestive system excretory, urinary and reproductive. In addition, it has attached glands, such as the liver and pancreas, which produce important secretions that aid in digestion. Columba is adapted for mode of life-bird. Oryctolagus Rabbit is a mammal. The digestive system consists of alimentary canal and its associated digestive glands.

The living of the alimentary canal is mostly endodermal in origin being derived from the wall of the archenteron. Distinc' salivary glands secreting enzymes are present only in mammals.

The secretions of which serve primarily to keep the mouth moist and secondarily to facilitate the movements of the tongue. The other connected with the midgut and arising as out growth are the liver and pancreas. Mouth is a wide, slit present at the anterior end of head.

Mouth is terminal, slitlike aperture bounded by horny Jaws. Mouth is sub-terminal, cleft bounded bv mobile, fleshy lips. Buccal cavity is a narrow gap. Labial glands are present on lips. Buccal cavity is narrow and some what and dorsoventrally flattened 2.

Buccal cavity is a spacious chamber andits space between lips and the teeth is called vestibule. This receives the mouth opening. On both jaws teet are present, polyphyodont homodont teeth arranged in a single row on each jaw. Teeth are not useful for mastication. Pleurodont dentition is present. Jaws are modified into tooth less beak. Teeth are diphyodont, heterodont and thecodont. These are arranged in a single row on each Jaw. Sensory papillae are present.

Tongue is narrow triangular and fleshy. Its surface is covered with horny material and bears thorn-like projections which carry taste buds and mucous glands. Tongue is highly specialized, fleshy and muscular and can be moved in different directions. It can be protruded out. Its surface is rugose being covered with numerous papillae along with taste buds. A pair of internal nostrils open into the roof of the buccal cavity anteriorly.

Hard palate is present. A bony palate is wanting in birds but a pair of palatal folds and palatal groove between the two folds are present.

Internal nostrils are located dorsal to the palatal folds. The nasal passages are separated from the buccal cavity by a bony palate. The internal nostrils open into the pharynx nearer to glottis.

A bony palate is present covering the roof of the buccal cavity. A bony palate is absent. But soft palate is formed of two membranous folds. The palate is differentiated into anterior bony hard palate and a soft palate is formed of connective tissue. The soft palate is produced behind into a process — velum palati hanging down from the roof, which prevents the entry of food into nasal passage. Unicellular mucous glands are present and keep the buccal cavity always wet.

Unicellular mucous glands are absent in the epithelium of bucco-pharyngeal region. Uni cellular mucous glands are absent. But multi cellular serous glands are present. Salivary glands are absent. But labial glands are open at the lips which do not play any role in digestion. Salivary glands which open into the buccal cavity are lingual, mandibular, maxillary, cricoary tenoid, palatinal and sphenopalatinal glands.

The multi cellular salaivary glands are four pairs. They are Infra orbital, parotid, sublingual and sub-maxillary glands. Pharynx is marked off. On the roof of pharynx near the junction of two jaws a pair of openings is called Eustachian apertures. Pharynx is not sharply demarcated from the buccal cavity. It receives the openings of esophagus and the glottis.