| Snot sea cucumber | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Holothuroidea |
| Order: | Apodida |
| Family: | Synaptidae |
| Genus: | Leptosynapta |
| Species: | L. dolabrifera |
| Binomial name | |
| Leptosynapta dolabrifera Stimpson, 1855 | |
Leptosynapta dolabrifera, the snot sea cucumber, is a small sea cucumber under the class Holothuroidea (1), in the family Synaptidae . It is most closely related to another species in its genus of 34 species Leptosynapta known as Leptosynapta inhaerens.
Snot sea cucumbers come in varying shapes and sizes, with lengths from 1.9 to 3.5 in (50-90mm) . The sea cucumber has small circular armored spines on its side to help in anchoring the creature and helping it to bury in the seafloor. Two to three toothed arms help to anchor and to extract nutrients from the substrate. There are no variations by sex (2). They are chubby with a pink, purple, red [1] or white body and they are often covered in mucus. The thickness and length of the Leptopsynapta dolabrifera can vary with the amount of body wall muscle. Many light-colored snot sea cucumbers have translucent body walls (8)
Leptosynapta dolabrifera has been known to inhabit areas around the coasts of Australia (3), and have also been recorded in Portland, Oregon (4) and some areas of Scotland in recent years. It prefers to inhabit temperate, shallow waters. Recent studies reveal that the average density of L. dolabrifera in an area is 0.20 (4). The sea snot cucumber is a favorite food of the Eastern shovelnose stingaree, making up 4.7% of their diet (5). L. dolabrifera is not thought to be endangered as of 2021.
The habitat L. dolabrifera lives in consists of nutrient rich substrate, either silty and fine substrate for shallow areas and dark, clay-like substrates for deeper waters (6). Sometimes, L. dolabrifera is seen in rockier areas, such as in coral skeletons in Edinburgh, Scotland (7).
Like most other sea cucumbers, snot sea cucumbers burrow themselves in sand or mud, and extracts nutrients with their tentacles. Their diet consists entirely of the substrates it consumes via digging into the sands and pushing substrate into its mouth with its anchors, leaving discarded trails of sand as waste behind.
Sea cucumbers in the genus Leptosynapta have the ability to regenerate parts of its body if certain sections are lost due to ecological or predatory circumstances. This process of regeneration is called morphallaxis, where any residual tissues of the sea cucumber are redifferentiated to produce a smaller, but complete, animal. When transections are made, any residual pieces that include both the mouth and part of the digestive tract are capable of regeneration. Although, the time that it takes to regenerate can vary depending on the location of transection. The anatomy of the sea cucumber consists of the esophagus, the stomach, and the intestine. The esophagus connects the mouth to the stomach, and it is the most anterior of this three-section digestive tract. The intestine is the most posterior of the three-section digestive tract, and it lies between the stomach and the anus. The stomach and esophagus are suspended in the dorsal mesentery, while the intestine is suspended in the ventral mesentery. In the mid-section of the Leptosynapta dolibrifera, the digestive tract crosses the coelomic cavity, and the area where the mesenteric attachment to the gut changes from dorsal to ventral orientation. This stomach-intestine junction is called the crossover point.
If a transection of the sea cucumber is made anteriorly to the crossover point, regeneration will occur, but the result will lack an intestine. Within 48 hours and 72 hours, the gut will slowly transition from its original dorsal attachment to a ventral attachment, moving posteriorly to anteriorly. The gut will continue to shift anteriorly until the original crossover point adjusts proportionally to the remaining sea cucumber body. The sea cucumber will be fully regenerated within 144 hours of transection.
If a transection of a sea cucumber is made posteriorly to the crossover point, then the esophagus, the stomach, and the intestine will all be represented in the final form of the sea cucumber. Similar processes as regeneration of an anterior transection will occur, and the sea cucumber will be considered completely regenerated between 120 and 144 hours of regeneration.
The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital digestive organ. In the digestive system the stomach is involved in the second phase of digestion, following chewing. It performs a chemical breakdown by means of enzymes and hydrochloric acid.
An echinoderm is any member of the phylum Echinodermata of marine animals. The adults are recognizable by their radial symmetry, and include starfish, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Adult echinoderms are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are the largest phylum that has no freshwater or terrestrial members.
The gastrointestinal tract is the tract from the mouth to the anus which includes all the organs of the digestive system in humans and other animals. Food taken in through the mouth is digested to extract nutrients and absorb energy, and the waste expelled as feces. The mouth, esophagus, stomach and intestines are all part of the gastrointestinal tract. Gastrointestinal is an adjective meaning of or pertaining to the stomach and intestines. A tract is a collection of related anatomic structures or a series of connected body organs.
A body cavity is any space or compartment, or potential space, in an animal body. Cavities accommodate organs and other structures; cavities as potential spaces contain fluid.
The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the pancreatic duct to aid in digestion. The small intestine is about 18 feet long and folds many times to fit in the abdomen. Although it is longer than the large intestine, it is called the small intestine because it is narrower in width.
Peristalsis is a radially symmetrical contraction and relaxation of muscles that propagates in a wave down a tube, in an anterograde direction. Peristalsis is progression of coordinated contraction of involuntary circular muscles, which is preceded by a simultaneous contraction of the longitudinal muscle and relaxation of the circular muscle in the lining of the gut.
Sea cucumbers are echinoderms from the class Holothuroidea. They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number of holothurian species worldwide is about 1,717 with the greatest number being in the Asia Pacific region. Many of these are gathered for human consumption and some species are cultivated in aquaculture systems. The harvested product is variously referred to as trepang, namako, bêche-de-mer or balate. Sea cucumbers serve a useful role in the marine ecosystem as they help recycle nutrients, breaking down detritus and other organic matter after which bacteria can continue the degradation process.
The myenteric plexus provides motor innervation to both layers of the muscular layer of the gut, having both parasympathetic and sympathetic input, whereas the submucous plexus has only parasympathetic fibers and provides secretomotor innervation to the mucosa nearest the lumen of the gut.
Extracellular Phototropic Digestion is a process in which saprobionts feed by secreting enzymes through the cell membrane onto the food. The enzymes catalyze the digestion of the food ie diffusion, transport, osmotrophy or phagocytosis. Since digestion occurs outside the cell, it is said to be extracellular. It takes place either in the lumen of the digestive system, in a gastric cavity or other digestive organ, or completely outside the body. "outside the thing ", and indicates that extracellular digestion must occur outside the cell. During extracellular digestion, food is broken down outside the cell either mechanically or with acid by special molecules called enzymes. Then the newly broken down nutrients can be absorbed by the cells nearby. Humans use extracellular digestion when they eat. Their teeth grind the food up, enzymes and acid in the stomach liquefy it, and additional enzymes in the small intestine break the food down into parts their cells can use. Extracellular digestion is a form of digestion found in all saprobiontic annelids, crustaceans, arthropods, lichens and chordates, including vertebrates.
The foregut is the anterior part of the alimentary canal, from the mouth to the duodenum at the entrance of the bile duct. Beyond the stomach, the foregut is attached to the abdominal walls by mesentery. The foregut arises from the endoderm, developing from the folding primitive gut, and is developmentally distinct from the midgut and hindgut. Although the term “foregut” is typically used in reference to the anterior section of the primitive gut, components of the adult gut can also be described with this designation. Pain in the epigastric region, just below the intersection of the ribs, typically refers to structures in the adult foregut.
Scoloplax is the only genus in the catfish family Scoloplacidae, the spiny dwarf catfishes.
Evisceration is a method of autotomy involving the ejection of internal organs used by animals as a defensive strategy. Sea cucumbers (Holothuroidea) eject parts of the gut in order to scare and defend against potential predators such as crabs and fish. The organs are regenerated in a few days by cells in the interior of the sea cucumber.
Synaptula lamperti is a species of sea cucumber in the family Synaptidae in the phylum Echinodermata, found on coral reefs in the Indo-Pacific region. The echinoderms are marine invertebrates and include the sea urchins, starfish and sea cucumbers. They are radially symmetric and have a water vascular system that operates by hydrostatic pressure, enabling them to move around by use of many suckers known as tube feet. Sea cucumbers are usually leathery, gherkin-shaped animals with a cluster of short tentacles at one end. They live on the sea bottom.
Holothuria scabra, or sandfish, is a species of sea cucumber in the family Holothuriidae. It was placed in the subgenus Metriatyla by Rowe in 1969 and is the type species of the subgenus. Sandfish are harvested and processed into "beche-de-mer" and eaten in China and other Pacific coastal communities.
Colochirus robustus, commonly known as the robust sea cucumber or the yellow sea cucumber, is a species of sea cucumber in the family Cucumariidae. It is found in shallow seas in tropical parts of the central Indo-Pacific region. C. robustus belongs to the class Holothuroidea, a group of echinoderms called sea cucumbers and known for unusual behavior including evisceration, asexual reproduction, and regeneration. The robust sea cucumber has a soft body and lacks a spine, but it does have an endoskeleton consisting of microscopic spicules, or ossicles, made of calcium carbonate. C. robustus has a respiratory tree that allows it to extract oxygen for respiration, using the anus to pump water. The robust sea cucumber is an important dietary staple for many East and Southeast Asian populations, and has been used for medicinal purposes for hundreds of years. Recent research suggests that peptides from C. robustus enhance the activity of the immune system.
The development of the digestive system in the human embryo concerns the epithelium of the digestive system and the parenchyma of its derivatives, which originate from the endoderm. Connective tissue, muscular components, and peritoneal components originate in the mesoderm. Different regions of the gut tube such as the esophagus, stomach, duodenum, etc. are specified by a retinoic acid gradient that causes transcription factors unique to each region to be expressed. Differentiation of the gut and its derivatives depends upon reciprocal interactions between the gut endoderm and its surrounding mesoderm. Hox genes in the mesoderm are induced by a Hedgehog signaling pathway secreted by gut endoderm and regulate the craniocaudal organization of the gut and its derivatives. The gut system extends from the oropharyngeal membrane to the cloacal membrane and is divided into the foregut, midgut, and hindgut.
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.
Thyonicola dogieli is a parasitic species of gastropod mollusc in the family Eulimidae. It parasitises sea cucumbers in the northeastern Pacific Ocean.
Thelenota rubralineata is a species of sea cucumber in the family Stichopodidae, in the phylum Echinodermata, mainly located in the central Indo-Pacific region. It has a distinctive coloring pattern, and can be found on the seabed near coral. T. rubralineata is part of the Thelenota genus, characterized by their large size and the presence of a calcareous ring.
Psychropotidae is a family of deep-sea swimming sea cucumbers. The geographic range of some psychropotids is very extensive at abyssal depths, whereas other species are found within more restricted ranges.
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