Unreferenced stub auto yes date December 2009 A tubule is a very small tube or fistula r structure. A system of surface connected membranes in muscle that enables a nerve impulse to travel to the interior of the muscle fibre. In anatomy , a tubule is a minute tube lined with glandular epithelium . Tubules can be found on poisonous sea creatures. These are tiny tubes in the biologial structure of the living items. The cells of the tubules remove certain molecules and ions from the blood and deposit these into the fluid within the tubules. br Category Histology Cell biology stub Anatomy stub simple Tubule ... more details
A T tubule or transverse tubule is a deep invagination of the sarcolemma , which is the plasma membrane , only found in skeletal muscle skeletal and cardiac muscle cells. These invaginations allow depolarization of the membrane to quickly penetrate to the interior of the cell. Structure Each muscle fiber is surrounded by a sarcolemma the muscle fiber s plasma membrane which invaginates perpendicular to the length of the fiber to form what is called a T tubule. At these invaginations the sarcolemma is studded with a large number of DHP receptor L type calcium channels . br br In skeletal muscle cells specifically, T tubule invaginations are typically located at the junction overlap between the A and I bands of the sarcomere , and together with a pair of terminal cisternae bulbous enlarged areas of the sarcoplasmic reticulum it forms an arrangement called a triad anatomy triad . br Cardiac muscle has a similar structure instead of a triad there is a diad , which is composed of a T tubule and a single terminal cisterna, and it occurs at the Sarcomere Bands Z line . br br It is physiologically important for excitation contraction coupling see section below that the T tubules are positioned close to the terminal cisternae of the sarcoplasmic reticulum as the triad anatomy triad or diad arrangement allows physical and functional contact by voltage dependent DHP receptor L type calcium channels . So, an action potential along the sarcolemma causes calcium channels to open in the terminal cisternae sarcoplasmic reticulum which enables calcium to move from the sarcoplasmic reticulum ... membrane. In skeletal muscle , the influx of calcium through the L type calcium channel on the T tubule ... the T tubule s L type calcium channel and the calcium release channel is critical to proper muscle ... that heart failure precipitates the loss of the T tubule network, again indicating their importance ... of the Cell cardiac muscle, intercalated disk eMedicineDictionary T tubule GeorgiaPhysiology ... more details
Unreferenced stub auto yes date December 2009 Orphan date December 2009 Convoluted tubule is the compound of a metanephridium which is wrapped with Capillary capillaries . The process of reabsorption occurs in this part of the metanephridium. References reflist DEFAULTSORT Convoluted Tubule Category Annelid anatomy Annelid stub ... more details
Infobox Anatomy Name PAGENAME Latin tubulus renalis arcuatus GraySubject 253 GrayPage 1223 Image Gray1128.png Caption Scheme of renal tubule and its vascular supply. Image2 Caption2 Precursor Metanephric blastema System Artery Vein Nerve Lymph MeshName MeshNumber DorlandsPre t 22 DorlandsSuf 12830099 In the kidney , the collecting tubule CNT , or junctional tubule , or arcuate renal tubule is a tubular segment of the renal collecting duct system that connects the distal convoluted tubule to the cortical collecting duct . Classification Many sources include the connecting tubule as part of the collecting duct system. However, the embryological origin is more similar to the nephron than it is to the rest of the collecting duct which derives from the ureteric bud , and other sources therefore classify the connecting tubule with the nephron. Naming Some connecting tubules, usually associated with nephron juxtamedullary nephron s, arch upwards before reaching the cortical collecting ducts. It is this arcuate feature which gives the tubule its alternate name. Function It participates in the regulation of water and electrolyte s, including sodium , and chloride . The CNT is sensitive to both isoprotenerol more so than the cortical collecting ducts and antidiuretic hormone less so than the cortical collecting ducts , the latter largely determining its function in water reabsorption. References cite book author Eaton, Douglas C., Pooler, John P. title Vander s Renal Physiology publisher Lange Medical Books McGraw Hill year 2004 edition 6th isbn 0 07 135728 9 cite journal author Imai M title The connecting tubule a functional subdivision of the rabbit distal nephron segments journal Kidney Int year 1979 pages 346 56 volume 15 issue 4 pmid 513494 doi 10.1038 ki.1979.46 External links GeorgiaPhysiology 7 7ch03 7ch03p18 http www.ndif.org Terms tubule.html Types of tubules at ndif.org http www.benet.org teachers meraci Biology FrBioReviews Review Excretory System review excretory ... more details
of seminiferous tubule cross section Image Rattestis.jpg thumb left 200px photomicrograph of rat ... seminifero ja pt Tubo semin fero simple Seminiferous tubule ... more details
Infobox Anatomy Name Proximal Convoluted Tubule Latin tubulus contortus proximalis GraySubject 253 GrayPage 1223 Image Gray1128.png Caption Scheme of renal tubule and its vascular supply. 1st convoluted tubule labeled at center top. Image2 Histology kidney.jpg Caption2 1 Glomerulus , 2 proximal tubule, 3 Distal convoluted tubule distal tubule Precursor Metanephric blastema System Artery Vein Nerve Lymph MeshName MeshNumber DorlandsPre t 22 DorlandsSuf 12830072 The proximal tubule is the portion of the Duct ... of Henle . Structure and appearance The most distinctive characteristic of the proximal tubule is its brush border or striated border . Brush border cell Renal proximal tubule brush border cell ... for the active transport of sodium ions out of the proximal tubule. Water passively follows ... tubule have extensive lateral interdigitations between neighboring cells, which lend an appearance ... tubular contents after interruption of circulation in the capillaries surrounding the tubule often leads to disturbance of the cellular morphology of the proximal tubule cells, including the ejection of cell nuclei into the tubule lumen. This has led some observers to describe the lumen ... , which have quite different properties. Divisions The proximal tubule as a part of the nephron ... divisions Description rowspan 4 Proximal tubule rowspan 2 convoluted S1 ref name boron743 cite book ... . Pars recta Proximal straight tubule redirects here The Pars recta is the following straight descending ... described above, this segment is sometimes designated as S3 . Absorption The proximal tubule ... and other bases, into the filtrate. Fluid in the filtrate entering the proximal convoluted tubule ... potential of the fluid leaving the proximal tubule is the same as that of the initial ... proximal tubule. ref Boron & Boulpaep. Medical Physiology. Updated Edition. 2005. ref phosphate ... the same. Secretion Many types of medications are secreted in the proximal tubule. Further ... more details
Infobox Anatomy Name Distal convoluted tubule Latin tubulus contortus distalis GraySubject 253 GrayPage 1223 Image Kidney nephron.png Caption Kidney nephron 1st proximal convoluted tubule , 2nd distal convoluted tubule Image2 Gray1132.png Caption2 Section of cortex of human kidney. Precursor Metanephric blastema System Artery Vein Nerve Lymph MeshName Distal Kidney Tubule MeshNumber DorlandsPre t 22 DorlandsSuf 12830066 The distal convoluted tubule DCT is a portion of kidney nephron between the loop of Henle and the collecting duct system . Physiology It is partly responsible for the regulation of potassium , sodium , calcium , and pH . It is the primary site for the kidneys hormone based regulation of calcium Ca . On its apical surface lumen side , cells of the DCT have a passive thiazide sensitive Na Cl cotransporter and are permeable to Ca. On the basolateral surface blood there is an ATP dependent Na K antiport pump, a secondary active Na Ca transporter antiport , and an ATP dependent Ca transporter. The basolateral ATP dependent Na K pump produces the gradient for Na to be absorbed from the apical surface via the Na Cl synport and for Ca to be reclaimed into the blood by the Na Ca apical antiport. It regulates pH by absorbing bicarbonate and secreting proton s H sup sup into the filtrate ... tubule is mediated by the hormone aldosterone . Aldosterone increases sodium reabsorption. Sodium ... proteins and enhancing the synthesis of all transporters within the distal convoluted tubule. Arginine ... reclamation associated with thiazide diuretics. Histology Kidney distal tubule cell redirects here The DCT is lined with simple cuboidal cells that are shorter than those of the proximal convoluted tubule ... from cells of the proximal convoluted tubule class wikitable Characteristic PCT DCT Apical ... 1 Glomerulus , 2 Proximal convoluted tubule proximal tubule , 3 distal tubule Image Gray1133.png ... distal fr N phron Tubule contourn distal he ja ... more details
Image Malpighian tube.svg thumb 350px right Stylised diagram of insect digestive tract showing malpighian tubule Orthopteran type The Malpighian tubule system is a type of excretory and osmoregulation osmoregulatory system found in some Uniramia Insect s and Myriapoda , arachnid s and tardigrade s. The system consists of branching tubule s extending from the alimentary canal that absorbs solution solutes , water, and wastes from the surrounding hemolymph . The wastes then are released from the organism in the form of solid nitrogenous compounds. The system is named after Marcello Malpighi , a seventeenth century anatomist. It is unclear as to whether the Malpighian tubules of arachnids and those of the Uniramia are homology biology homologous or the result of convergent evolution . Structure Malpighian tubules are slender tubes normally found in the posterior regions of arthropod alimentary canals. Each tubule consists of a single layer of cells that is closed off at the distal end with the proximal end joining the alimentary canal at the junction between the midgut and hindgut. Most tubules are normally highly convoluted. The number of tubules varies between species although most occur in multiples of two. Tubules are usually bathed in hemolymph and are in proximity to fat body tissue. They contain actin for structural support and microvilli for propulsion of substances along the tubules. Malpighian tubules in most insects also contain accessory musculature associated with the tubules which may function to mix the contents of the tubules or expose the tubules to more hemolymph. The insect orders, Thysanura , Dermaptera and Thysanoptera do not possess these muscles and Collembola and Hemiptera Aphididae completely lack a Malpighian tubule system. General Mode of Action Pre urine is formed in the tubules, when nitrogenous waste and electrolytes are transported through the tubule walls. Wastes such as Urea and amino acids are thought to diffuse through the walls, whil ... more details
Tubular fluid is the fluid in the renal tubule tubules of the kidney . It starts as a Ultrafiltration renal renal ultrafiltrate in the glomerulus , changes composition through the nephron , and ends up as urine leaving through the ureter s. Composition table The composition of tubular fluid changes throughout the nephron, from the proximal tubule to the collecting duct Class wikitable Concentration m Concentration Molarity M of substances in different segments of nephron and collecting duct system rowspan 2 Substance colspan 3 proximal tubule colspan 3 loop of Henle rowspan 2 Distal convoluted tubule colspan 4 Collecting duct system S1 S2 S3 Descending limb of loop of Henle descending limb thin ascending limb of loop of Henle thin ascending limb thick ascending limb of loop of Henle thick ascending limb connecting tubule initial collecting tubule cortical collecting ducts medullary collecting ducts sodium Na sup sup 142 ref name boron777 cite book author Walter F., PhD. Boron title Medical Physiology A Cellular And Molecular Approaoch publisher Elsevier Saunders location year pages isbn 1 4160 2328 3 oclc doi Page 777 ref 142 ref name boron777 100 ref name boron777 70 ref name boron777 40 ref name boron777 References reflist Category Kidney Category Urology ... more details
Hemosiderinuria syn. haemosiderinuria , brown urine , occurs with chronic intravascular hemolysis , in which hemoglobin is released from RBCs into the bloodstream in excess of the binding capacity of haptoglobin . The excess hemoglobin is filtered by the kidney and reabsorbed in the proximal tubule, where the iron portion is removed and stored in ferritin or hemosiderin . The tubule cells of the proximal tubule slough off with the hemosiderin and are excreted into the urine, producing a brownish color. It is usually seen 3 4 days after the onset of hemolytic conditions. Hemoglobinuria is another indicator of intravascular hemolysis, but disappears more quickly than hemosiderin, which can remain in the urine for several weeks therefore, hemosiderinuria is a better marker for intravascular hemolysis. Category Hematology med sign stub ... more details
Orphan date September 2006 att March 2011 The holonephros is the kidney of the larva e of Agnatha cyclostome s and some amphibian s. The entire mass of nephrogenic tissue gives rise to this kidney, which is usually of simple form with a single Nephron Renal tubule tubule in each segment. External links http www.lander.edu rsfox 30urogenitalLec.html Comparative Vertebrate Anatomy, BIOLOGY 308, Urogenital System, Richard Fox, Lander University Category Urinary system ... more details
A carboxylate transporter is a membrane transport protein that transports carboxylate . They are responsible for the reabsorption of filtered carboxylate in renal physiology , resulting in a 100 ref name boron799 cite book author Walter F., PhD. Boron title Medical Physiology A Cellular And Molecular Approaoch publisher Elsevier Saunders location year pages isbn 1 4160 2328 3 oclc doi Page 799 ref reabsorption in the proximal tubule . In proximal tubule In the renal proximal tubule , there are several kinds of carboxylate transporters in the apical membrane and the basolateral membrane . Apical sodium Na monocarboxylate cotransporter 3Na dicarboxylate cotransporter 3Na tricarboxylate cotransporter Basolateral hydrogen H monocarboxylate cotransporter ref name boron799 organic anion dicarboxylate exchanger References reflist Category Transport proteins medicine stub ... more details
Unreferenced stub auto yes date December 2009 Nephridiopore is part of the nephridia , an Excretion excretory Organ anatomy organ found in many organism s, such as flatworm s or annelid s. Nephridia are analogous to nephron s or uriniferous tubules found in the kidney of humans. The nephridia consists of an opening called nephrostome , a long convoluted tubule and another opening called the nephridiopore. Body fluids are Filtration filtered in through the nephrostome and passed through the convoluted tubule system. Essential substances are Reabsorption reabsorbed through active mechanisms and waste products are Secretion secreted back into the lumen of the tube. The resulting excretory fluid or urine is passed out through the nephridiopore. References reflist Category Platyhelminth anatomy Category Annelid anatomy Invertebrate stub ... more details
A chloride hydroxyl exchanger is a purported membrane transport protein , responsible for the exchange of chloride and hydroxyl in the renal proximal tubule , functioning in renal chloride reabsorption . However, little is known about the protein responsible for this action. ref http www.nature.com ki journal v50 n6 abs ki1996513a.html Functional identity of a purified proximal tubule anion exchanger protein Mediation of chloride formate and chloride bicarbonate exchange ref . References reflist membrane transport proteins Carrier proteins Ion channels Ion pumps Neurotransmitter transporters Category Transport proteins Category Transmembrane transporters membrane protein stub ... more details
component the renal corpuscle and a tubule specialized for reabsorption and secretion the renal tubule . The renal corpuscle filters out large solutes from the blood, delivering water and small solutes to the renal tubule for modification. Renal corpuscle Composed of a glomerulus kidney glomerulus ... . Renal tubule Renal tubule redirects here Infobox Anatomy Name Renal tubule Latin tubulus renalis ... t 22 DorlandsSuf 12830093 The renal tubule is the portion of the nephron containing the tubular ... at Boulder. The Kidney Tubule I Urine Production. URL http www.colorado.edu eeb web resources cartoons ... 6, 2007. ref After passing through the renal tubule, the filtrate continues to the collecting duct system , which is not part of the nephron. The components of the renal tubule are Proximal convoluted tubule Loop of Henle Descending limb of loop of Henle Ascending limb of loop of Henle Thin ascending limb of loop of Henle Thick ascending limb of loop of Henle Distal convoluted tubule Functions ... has highly specialized functions. The proximal tubule as a part of the nephron can be divided into an initial ... the proximal convoluted tubule is reabsorbed into the peritubular capillaries, including approximately ... tube that extends from the proximal tubule. It consists of a descending limb and ascending limb. It begins in the cortex, receiving filtrate from the proximal straight tubule, extends into the medulla ... convoluted tubule. The primary role of the loop of Henle is to concentrate the salt in the interstitium ... convoluted tubule in the renal cortex. The distal convoluted tubule has a different structure and function to that of the proximal convoluted tubule. Cells lining the tubule have numerous mitochondria ... transport taking place in the distal convoluted tubule is regulated by the endocrine system . In the presence of parathyroid hormone , the distal convoluted tubule reabsorbs more calcium and excretes ... excreted. Atrial natriuretic peptide causes the distal convoluted tubule to excrete more sodium. In addition ... more details
Renal oligopeptide reabsorption is the part of renal physiology that deals with the retrieval of filtered oligopeptide s, preventing them from disappearing from the body through the urine. Almost all reabsorption takes place in the proximal tubule . Practically nothing is left in the final urine. Longer oligopeptides, such as angiotensin ref name boron798 and glutathione ref name boron798 are degraded by enzymes on the brush border , while shorter ones, such as carnosine ref name boron798 , are transported across the apical membrane as a whole by the PepT 1 transporter, and degraded inside the proximal tubule cell . Overview table Class wikitable Characteristics of oligopeptide reabsorption rowspan 2 Characteristic colspan 3 proximal tubule rowspan 2 loop of Henle rowspan 2 Distal convoluted tubule rowspan 2 Collecting duct system S1 S2 S3 reabsorption colspan 3 99 ref name boron798 cite book author Walter F., PhD. Boron title Medical Physiology A Cellular And Molecular Approaoch publisher Elsevier Saunders location year pages isbn 1 4160 2328 3 oclc doi Page 798 ref colspan 3 Beyond the proximal tubule 1 ref name boron798 reabsorption m Mole unit moles day Concentration apical membrane apical transport proteins colspan 3 sodium amino acid symporter ref name boron798 PepT 1 for short peptides, n 2 to 4 ref name boron798 basolateral membrane basolateral transport proteins colspan 3 amino acid transporter ref name boron798 Other reabsorption features References reflist renal physiology Category Renal physiology ... more details
Renal protein reabsorption is the part of renal physiology that deals with the retrieval of filtered protein s, preventing them from disappearing from the body through the urine. Almost all reabsorption takes place in the proximal tubule . Only 1 ref name boron798 is left in the final urine. The proteins cross the apical membrane by endocytosis . They are subsequently degraded in lysosome s. The remaining free amino acids are transported across the basolateral membrane by amino acid transporter s. ref name boron798 Overview table Class wikitable Characteristics of oligopeptide reabsorption rowspan 2 Characteristic colspan 3 proximal tubule rowspan 2 loop of Henle rowspan 2 Distal convoluted tubule rowspan 2 Collecting duct system S1 S2 S3 reabsorption colspan 3 99 ref name boron798 cite book author Walter F., PhD. Boron title Medical Physiology A Cellular And Molecular Approaoch publisher Elsevier Saunders location year pages isbn 1 4160 2328 3 oclc doi Page 798 ref colspan 3 reabsorption m Mole unit moles day Concentration apical membrane apical transport colspan 3 endocytosis ref name boron798 basolateral membrane basolateral transport proteins colspan 3 amino acid transporter ref name boron798 Other reabsorption features References reflist renal physiology Category Renal physiology ... more details
working of osmotic diuretics The renal proximal tubule is the primary site of action of osmotic diuretics. Normally, water molecules follow Na sup sup out of the proximal tubule, resulting in Na sup ... in the tubule. Since the luminal membrane is quite leaky to Na sup sup , this causes a high back leak of Na sup sup into the tubule. Na sup sup is normally followed by K sup sup and Cl sup sup out of the proximal tubule. When there is high back leak of Na sup sup , these electrolytes stay in the tubule ... more details
connecting tubule initial collecting tubule Before convergence of nephrons cortical collecting ducts medullary collecting ducts papillary ducts , also known as duct of Bellini Connecting tubule Main Connecting tubule With respect to the renal corpuscle , the connecting tubule is the most proximal part of the collecting duct system. It is adjacent to the distal convoluted tubule , the most distal segment of the renal tubule . Connecting tubules from several adjacent nephrons merge to form cortical ... juxtamedullary nephron s may arch upward, forming an arcade. The connecting tubule derives from ... sources group the connecting tubule as part of the nephron , rather than grouping it with the collecting duct system. Initial collecting tubule Initial collecting tubule redirects here The initial collecting tubule is a segment with a constitution similar as the collecting duct, but before the convergence ... is the connecting tubule cell For the collecting ducts, it is the principal cell . The inner medullary ... Duct Kidney BUHistology 15803loa Urinary System kidney, medulla, collecting duct and ascending tubule BUHistology 16013loa Urinary System kidney, H&E, collecting duct and ascending tubule kidney DEFAULTSORT ... more details
A nephron of the kidney. from Gray s Anatomy 1918. Important to note is the anatomical error that the distal tubulus does not pass by the vascular pole of the glomerulus before becoming the distal convoluted tubule. The distal tubulus together with the afferent arteriole and the extra glomerular mesangial cells together make up the juxtaglomerular apparatus . This occurs in all nephrons but was not known in 1918. PD old 100 ... more details
Transmission electron microscopy Transmission Electron Micrograph of negatively stained Proximal convoluted tubule of Rat kidney tissue at a magnification of 55,000x and 80KV. Note the Zonula occludens Tight Junction right of center, the Mitochondria in the upper left and Microvilli in cross section in the lower right. Micrograph taken by Eric Yale Hayden December, 2002. Cc by sa 2.5 Attribution to Eric Yale Hayden Category Electron microscope images ... more details
Infobox Anatomy Name PAGENAME Latin tubulus rectus distalis GraySubject 253 GrayPage 1223 Image Gray1128.png Caption Scheme of renal tubule and its vascular supply. Labeled at center left. Image2 Kidney nephron molar transport diagram.png Caption2 Nephron ion flow diagram Precursor System Artery Vein Nerve Lymph MeshName MeshNumber DorlandsPre t 22 DorlandsSuf 12830078 The thick ascending limb of loop of Henle TAL also known as distal straight tubule , is a segment of the nephron in the kidney . It can be divided into two parts that in the renal medulla , and that in the renal cortex . Medullary thick ascending limb The medullary thick ascending limb remains impermeable to water. Sodium, potassium K sup sup and chloride Cl sup sup ions are reabsorbed by active transport . K sup sup is passively transported along its concentration gradient through a K sup sup leak channel in the apical aspect of the cells, back into the lumen of the ascending limb. This K sup sup leak generates a positive electrochemical potential difference in the lumen. The electrical gradient drives more reabsorption of Na sup sup , as well as other cation s such as magnesium Mg sup 2 sup and importantly calcium Ca sup 2 sup . Loop diuretic s such as furosemide block the Na K 2Cl symporter K sup sup Na sup sup 2Cl sup sup co transporter . This is also the part of the tubule that generates Tamm Horsfall protein . The function of this protein is not well understood, but is responsible for creating urinary casts . Cortical thick ascending limb The difference between the medullary and cortical thick ascending limbs is mainly anatomy anatomical . Functionally, they are very similar. The cortical thick ascending limb drains urine into the distal convoluted tubule . External links GeorgiaPhysiology 7 7ch07 7ch07p11 BUHistology 15804loa http www.diaglab.vet.cornell.edu clinpath modules ua rout sg.htm Overview at vet.cornell.edu Gray s genitourinary stub Kidney Category Kidney anatomy ja ... more details
Encyclopedia
top
