Digestion is the breakdown of large insoluble food compounds into small water-soluble components so that they can be absorbed into the blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion. The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. Mechanical digestion takes place in the mouth through mastication and in the small intestine through segmentation contractions. In chemical digestion, enzymes break down food into the small compounds that the body can use.
The esophagus or oesophagus, colloquially known also as the food pipe, food tube, or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to the stomach. The esophagus is a fibromuscular tube, about 25 cm (10 in) long in adults, that travels behind the trachea and heart, passes through the diaphragm, and empties into the uppermost region of the stomach. During swallowing, the epiglottis tilts backwards to prevent food from going down the larynx and lungs. The word oesophagus is from Ancient Greek οἰσοφάγος (oisophágos), from οἴσω (oísō), future form of φέρω + ἔφαγον.
Gastropods, commonly known as slugs and snails, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda.
The radula is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus. The radula is unique to the mollusks, and is found in every class of mollusk except the bivalves, which instead use cilia, waving filaments that bring minute organisms to the mouth.
Digestive enzymes are a group of enzymes that break down polymeric macromolecules into their smaller building blocks, in order to facilitate their absorption into the cells of the body. Digestive enzymes are found in the digestive tracts of animals and in the tracts of carnivorous plants, where they aid in the digestion of food, as well as inside cells, especially in their lysosomes, where they function to maintain cellular survival. Digestive enzymes of diverse specificities are found in the saliva secreted by the salivary glands, in the secretions of cells lining the stomach, in the pancreatic juice secreted by pancreatic exocrine cells, and in the secretions of cells lining the small and large intestines.
Schizoglossa novoseelandica is a predatory species of air-breathing land slug or semi-slug, a terrestrial gastropod mollusc in the family Rhytididae. It is the type species of the genus Schizoglossa and is found only in New Zealand. The survival of this species is not threatened; it is not listed in the 2009 IUCN Red List nor is it in the 2005 New Zealand Threat Classification System lists.
Odontogriphus is a genus of soft-bodied animals known from middle Cambrian Lagerstätte. Reaching as much as 12.5 centimetres (4.9 in) in length, Odontogriphus is a flat, oval bilaterian which apparently had a single muscular foot and a "shell" on its back that was moderately rigid but of a material unsuited to fossilization.
The mouth is the body orifice through which many animals ingest food and vocalize. The body cavity immediately behind the mouth opening, known as the oral cavity, is also the first part of the alimentary canal which leads to the pharynx and the gullet. In tetrapod vertebrates, the mouth is bounded on the outside by the lips and cheeks — thus the oral cavity is also known as the buccal cavity — and contains the tongue on the inside. Except for some groups like birds and lissamphibians, vertebrates usually have teeth in their mouths, although some fish species have pharyngeal teeth instead of oral teeth.
Zonitoides arboreus, commonly known as the quick gloss snail, is a species of small air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Gastrodontidae.
Fiona pinnata, common name Fiona, is a species of small pelagic nudibranch, a marine gastropod mollusk in the superfamily Fionoidea. This nudibranch species lives worldwide on floating objects on seas, and feeds mainly on barnacles, specifically goose barnacles in the genus Lepas.
Phyllidiidae is a family of sea slugs, dorid nudibranchs, marine gastropod mollusks in the superfamily Phyllidioidea.
The excretory system of gastropods removes nitrogenous waste and maintains the internal water balance of these creatures, commonly referred to as snails and slugs. The primary organ of excretion is a nephridium.
The nervous system of gastropods consists of a series of paired ganglia connected by major nerve cords, and a number of smaller branching nerves. It is sometimes called ganglionic.
Pseudunela cornuta is a species of minute sea slug, an acochlidian, a shell-less marine and temporarily brackish gastropod mollusk in the family Pseudunelidae. Adults are about 3 mm long and live in the spaces between sand grains.
Spergo glandiniformis is a species of sea snail, a marine gastropod mollusk in the family Raphitomidae.
Careoradula perelegans is a species of air-breathing land snail, terrestrial pulmonate gastropod mollusk in the family Streptaxidae.
Bathyacmaea nipponica is a species of very small, deep-sea limpet, a marine gastropod mollusk in the family Pectinodontidae.
The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion. Digestion involves the breakdown of food into smaller and smaller components, until they can be absorbed and assimilated into the body. The process of digestion has three stages: the cephalic phase, the gastric phase, and the intestinal phase.
Rathouisia pantherina is a species of carnivorous air-breathing land slug, terrestrial pulmonate gastropod mollusk in the family Rathouisiidae.
This outline is provided as an overview of, and organized list of articles relevant to, the subject of gastropods :
