Введение
Коксальная железа — железа, обнаруженная у некоторых членистоногих, служащая для сбора и выведения мочи. Она встречается у всех паукообразных (за исключением некоторых клещей) и у других хелицерат, таких как ракоскорпионы. Считается, что коксальная железа гомологична антеннальным железам ракообразных. Железа состоит из конечного мешка (саккулы), длинного протока (лабиринта) и конечного резервуара. Обычно имеется только одна пара (у некоторых пауков — две), и они открываются на коксах ног.
The coxal gland is a gland found in some arthropods, for collecting and excreting urine. They are found in all arachnids (with the exception of some Acari), and in other chelicerates, such as horseshoe crabs. The coxal gland is thought to be homologous with the antennal gland of crustaceans. The gland consists of an end sac (saccule), a long duct (labyrinth) and a terminal bladder (reservoir). There is generally only one pair (two in some spiders), and they open on the coxae of the walking legs.
Выделяющая система
В выделительной системе креветок отсутствует настоящая почка. В ее выделительной системе находятся следующие части:
Antennal or green glands: A pair of enteric glands are found in the coxa (Grap) of each antenna. They are green in color, hence the name "green gland." The antennal gland consists of four regions:
End sac: This is the smallest part which is bean shaped. It is located between the bladder and the labrum. Inside it is a large blood facuna. It has two levels in the wall. Its walls have numerous blood vessels which are the outer layer, the inner layer is thin and contains large excretory epithelial cells. The end sac functions similarly to the vertebrate glomerular nephron. Labyrinth: The labyrinth is highly coiled and is made up of branched excretory tubules. Blood vessels are found in the connective tissue mass. These ducts have a large excretory system which are covered by a single layer of cells. The labyrinth is involved with the movement of ions and reabsorption of proteins. Bladder: This is the inner side of the last cell and is the largest part. It is made up of a single layer of excretory epithelium. Its inner wall emerges to form a small ureter or ureter. The ureter is enclosed outside by a round renal aperture, which is located on the inner surface of the coxa of the antennae on top of a papilla. The bladder stores urine. A ureter connects the bladder to the nephropore (excretory pore) under the base of the second antennae. Lateral ducts: A narrow lateral duct emerges from the bladder of each hyaline gland at the back. The lateral vessels on either side are joined by a transverse connective in front of the brain. After this, moving backward along both the esophagus opens into the renal sac.
Антенные или зеленые железы: пара кишечных желез расположена в коксе (Grap) каждой антенны. Они имеют зеленый цвет, отсюда и название "зеленые железы". Антенная железа состоит из четырех отделов:
Antennal or green glands: A pair of enteric glands are found in the coxa (Grap) of each antenna. They are green in color, hence the name "green gland." The antennal gland consists of four regions:
End sac: This is the smallest part which is bean shaped. It is located between the bladder and the labrum. Inside it is a large blood facuna. It has two levels in the wall. Its walls have numerous blood vessels which are the outer layer, the inner layer is thin and contains large excretory epithelial cells. The end sac functions similarly to the vertebrate glomerular nephron. Labyrinth: The labyrinth is highly coiled and is made up of branched excretory tubules. Blood vessels are found in the connective tissue mass. These ducts have a large excretory system which are covered by a single layer of cells. The labyrinth is involved with the movement of ions and reabsorption of proteins. Bladder: This is the inner side of the last cell and is the largest part. It is made up of a single layer of excretory epithelium. Its inner wall emerges to form a small ureter or ureter. The ureter is enclosed outside by a round renal aperture, which is located on the inner surface of the coxa of the antennae on top of a papilla. The bladder stores urine. A ureter connects the bladder to the nephropore (excretory pore) under the base of the second antennae. Lateral ducts: A narrow lateral duct emerges from the bladder of each hyaline gland at the back. The lateral vessels on either side are joined by a transverse connective in front of the brain. After this, moving backward along both the esophagus opens into the renal sac.
Конечный мешок: Это самая маленькая часть, имеющая форму боба. Он расположен между мочевым пузырем и лабрумом. Внутри находится большая кровяная лакуна. В его стенке выделяют два слоя. Стенки содержат многочисленные кровеносные сосуды, составляющие наружный слой, а внутренний слой тонкий и содержит крупные экскреторные эпителиальные клетки. Конечный мешок функционирует аналогично гломерулярному нефрону позвоночных.
Antennal or green glands: A pair of enteric glands are found in the coxa (Grap) of each antenna. They are green in color, hence the name "green gland." The antennal gland consists of four regions:
End sac: This is the smallest part which is bean shaped. It is located between the bladder and the labrum. Inside it is a large blood facuna. It has two levels in the wall. Its walls have numerous blood vessels which are the outer layer, the inner layer is thin and contains large excretory epithelial cells. The end sac functions similarly to the vertebrate glomerular nephron. Labyrinth: The labyrinth is highly coiled and is made up of branched excretory tubules. Blood vessels are found in the connective tissue mass. These ducts have a large excretory system which are covered by a single layer of cells. The labyrinth is involved with the movement of ions and reabsorption of proteins. Bladder: This is the inner side of the last cell and is the largest part. It is made up of a single layer of excretory epithelium. Its inner wall emerges to form a small ureter or ureter. The ureter is enclosed outside by a round renal aperture, which is located on the inner surface of the coxa of the antennae on top of a papilla. The bladder stores urine. A ureter connects the bladder to the nephropore (excretory pore) under the base of the second antennae. Lateral ducts: A narrow lateral duct emerges from the bladder of each hyaline gland at the back. The lateral vessels on either side are joined by a transverse connective in front of the brain. After this, moving backward along both the esophagus opens into the renal sac.
Лабиринт: Лабиринт сильно извит и состоит из разветвленных экскреторных канальцев. Кровеносные сосуды находятся в массе соединительной ткани. Эти канальцы имеют развитую экскреторную систему, покрытую одним слоем клеток. Лабиринт участвует в транспорте ионов и реабсорбции белков.
Antennal or green glands: A pair of enteric glands are found in the coxa (Grap) of each antenna. They are green in color, hence the name "green gland." The antennal gland consists of four regions:
End sac: This is the smallest part which is bean shaped. It is located between the bladder and the labrum. Inside it is a large blood facuna. It has two levels in the wall. Its walls have numerous blood vessels which are the outer layer, the inner layer is thin and contains large excretory epithelial cells. The end sac functions similarly to the vertebrate glomerular nephron. Labyrinth: The labyrinth is highly coiled and is made up of branched excretory tubules. Blood vessels are found in the connective tissue mass. These ducts have a large excretory system which are covered by a single layer of cells. The labyrinth is involved with the movement of ions and reabsorption of proteins. Bladder: This is the inner side of the last cell and is the largest part. It is made up of a single layer of excretory epithelium. Its inner wall emerges to form a small ureter or ureter. The ureter is enclosed outside by a round renal aperture, which is located on the inner surface of the coxa of the antennae on top of a papilla. The bladder stores urine. A ureter connects the bladder to the nephropore (excretory pore) under the base of the second antennae. Lateral ducts: A narrow lateral duct emerges from the bladder of each hyaline gland at the back. The lateral vessels on either side are joined by a transverse connective in front of the brain. After this, moving backward along both the esophagus opens into the renal sac.
Мочевой пузырь: Это самая большая часть, расположенная на внутренней стороне последнего отдела. Он состоит из одного слоя экскреторного эпителия. Его внутренняя стенка образует небольшой мочеиспускательный канал, или уретру. Уретра снаружи окружена круглым почечным отверстием, расположенным на внутренней поверхности коксы антенны на вершине сосочка. Мочевой пузырь служит для хранения мочи. Уретра соединяет мочевой пузырь с нефропорой (выделительным отверстием), расположенной под основанием второй антенны.
Antennal or green glands: A pair of enteric glands are found in the coxa (Grap) of each antenna. They are green in color, hence the name "green gland." The antennal gland consists of four regions:
End sac: This is the smallest part which is bean shaped. It is located between the bladder and the labrum. Inside it is a large blood facuna. It has two levels in the wall. Its walls have numerous blood vessels which are the outer layer, the inner layer is thin and contains large excretory epithelial cells. The end sac functions similarly to the vertebrate glomerular nephron. Labyrinth: The labyrinth is highly coiled and is made up of branched excretory tubules. Blood vessels are found in the connective tissue mass. These ducts have a large excretory system which are covered by a single layer of cells. The labyrinth is involved with the movement of ions and reabsorption of proteins. Bladder: This is the inner side of the last cell and is the largest part. It is made up of a single layer of excretory epithelium. Its inner wall emerges to form a small ureter or ureter. The ureter is enclosed outside by a round renal aperture, which is located on the inner surface of the coxa of the antennae on top of a papilla. The bladder stores urine. A ureter connects the bladder to the nephropore (excretory pore) under the base of the second antennae. Lateral ducts: A narrow lateral duct emerges from the bladder of each hyaline gland at the back. The lateral vessels on either side are joined by a transverse connective in front of the brain. After this, moving backward along both the esophagus opens into the renal sac.
Боковые каналы: Узкий боковой канал отходит от мочевого пузыря каждой гиалиновой железы сзади. Боковые сосуды с обеих сторон соединены поперечным соединительным каналом перед мозгом. Затем, двигаясь назад вдоль пищевода, они открываются в почечный мешок.
Antennal or green glands: A pair of enteric glands are found in the coxa (Grap) of each antenna. They are green in color, hence the name "green gland." The antennal gland consists of four regions:
End sac: This is the smallest part which is bean shaped. It is located between the bladder and the labrum. Inside it is a large blood facuna. It has two levels in the wall. Its walls have numerous blood vessels which are the outer layer, the inner layer is thin and contains large excretory epithelial cells. The end sac functions similarly to the vertebrate glomerular nephron. Labyrinth: The labyrinth is highly coiled and is made up of branched excretory tubules. Blood vessels are found in the connective tissue mass. These ducts have a large excretory system which are covered by a single layer of cells. The labyrinth is involved with the movement of ions and reabsorption of proteins. Bladder: This is the inner side of the last cell and is the largest part. It is made up of a single layer of excretory epithelium. Its inner wall emerges to form a small ureter or ureter. The ureter is enclosed outside by a round renal aperture, which is located on the inner surface of the coxa of the antennae on top of a papilla. The bladder stores urine. A ureter connects the bladder to the nephropore (excretory pore) under the base of the second antennae. Lateral ducts: A narrow lateral duct emerges from the bladder of each hyaline gland at the back. The lateral vessels on either side are joined by a transverse connective in front of the brain. After this, moving backward along both the esophagus opens into the renal sac.
Сообщение
У беспозвоночных с коксальными железами многие формы коммуникации передаются посредством химических веществ в моче. Ряд исследований показал, что у раков эти химические вещества передают информацию о репродуктивной способности, индивидуальной идентификации, а также об уровне агрессии и иерархическом статусе. Например, при встрече двух самцов раков они вступают в бой. Результат боя определяет, какой из особей является "доминантным", а какой – "подчиненным" в иерархии. Эти столкновения влияют на уровень их агрессии, регулируемый серотонином, и, следовательно, изменяют химический состав мочи. Эти изменения в химическом составе будут влиять на последующие взаимодействия, обеспечивая ракам определенную степень "знакомства" друг с другом. Химические вещества в моче сообщают другим ракам об их ранге, и хотя интенсивность столкновения остается прежней, его продолжительность значительно сокращается.
Сбой связи
Инородные химические вещества, попадающие в экосистему, могут нарушать работу химических рецепторов членистоногих. Показано, что смыв инсектицидов с сельскохозяйственных угодий подавляет коммуникацию у раков. Неоникотиноиды – это широко используемые системные инсектициды, которые действуют как нейротоксин для большинства водных членистоногих и часто попадают в различные водоемы. Неоникотиноиды связываются с никотиновыми ацетилхолиновыми рецепторами (nAChR), что приводит к гибели насекомых из-за чрезмерной стимуляции. nAChR находятся в интернейронах мозга, нейромышечных соединениях и обонятельной луковице. Связывание неоникотиноидов с этими рецепторами блокирует связывание химических веществ, участвующих в коммуникации, с их целевыми рецепторами. В результате, раки, подвергшиеся воздействию этих инсектицидов в сублетальных дозах, теряют способность распознавать определенные сигналы. Они перестают узнавать особей, с которыми ранее контактировали, а также определять их иерархическое положение. Раки также теряют способность находить пищу, и лабораторные эксперименты демонстрируют, что они не проявляют предпочтения к среде обитания с пищей или без нее.