Digestive system

The digestive system is the whole of the Organe S which at the animal has as a role to ensure ingestion and the Digestion of the Aliment S to extract the energy from it and the Nutriment S necessary to the survival of the Organisme which are then to absorb by the organization. This system is essential with the life of the animals and is necessarily found for all the species. The role of the digestive system is also to ensure the excretion of the food matters which could not be absorptive by the organization.

The digestive system varies in a more or less important way of an animal to another. It can be very simple as that of the Nématode S (compound only of a Bouche, of a Pharynx, a Intestin and a Anus) that much more complex as that of the Ruminant S which have of several additional bodies and a Estomac with several rooms.

The study of the digestive system of an animal makes it possible to determine many things on its mode and food behavior. Thus with only the Dent S, the anthropologist S are able to determine if a Hominidé were in majority Herbivore or Omnivore.

Role

The plants are able to produce organic compounds (they are Autotrophe S), contrary to the animals which are unable and are thus obliged to nourish living beings (they are Hétérotrophe S). The introduced organic compounds are used for two things:

like energy source, recovered between let us liasons
as elements which the organization is unable to synthesize, are the mineral nutrients and essential

The organic molecules to introduce are relatively complex and require to be digested by the organization to be reduced in smaller molecules. Once reduced, they are absorbed, all the other elements are evacuated digestive system.

Types

Although the sponge S are animals, the digestion of their food is intracellular, like the Bactérie S. But of the more complex animals, like the Hydre, developed a cavity gastrovasculaire or food is conveyed to be there digested under the effect of various Enzyme S.

The digestive system specializes when there is a separation of the Bouche (by where food penetrates) and the Anus (by where waste is expelled). In the case of the hydre, the mouth and the anus are indéfférenciés, which are not the case of the Nématode which developed an one-way tract digestive where food passes successively by the Bouche, the Pharynx, the Intestin and the Anus.

According to their mode food, the animals are classified in three groups:

the Herbivore S, which nourish exclusively plants
the Carnivore S, which nourish exclusively other animals
the Omnivore S, which nourish as well plants as animals

These food modes required the specialization of all the bodies composing the digestive system.

Stop

Tooth

Pharynx

Esophagus

Stomach

Gizzard

Intestine

Small intestine

Colon

Anus

Additional bodies

August 1st

Liver

Gall bladder

Pancreas

See too

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