"Loop of Henle In the kidney, the loop of Henle () (or Henle's loop, Henle loop, nephron loop or its Latin counterpart ansa nephroni) is the portion of a nephron that leads from the proximal convoluted tubule to the distal convoluted tubule. Named after its discoverer, the German anatomist Friedrich Gustav Jakob Henle, the loop of Henle's main function is to create a concentration gradient in the medulla of the kidney. By means of a countercurrent multiplier system, which uses electrolyte pumps, the loop of Henle creates an area of high urea concentration deep in the medulla, near the papillary"
"Crypts of Henle Crypts of Henle are microscopic pockets found in scattered sections of the conjunctiva around the eyeball. They are responsible for secreting mucin, a proteinous substance that makes up the inner layer of tears. It coats the cornea to provide a hydrophilic layer that allows for even distribution of the tear film. The layer of mucin allows tears to glide evenly across the eye’s surface. The crypts of Henle are named after German anatomist Friedrich Gustav Jakob Henle (1809-1885). Another anatomical structure called the ""glands of Manz"" perform a similar function. They are located in the eyeball's conjunctiva,"
"on the basal lateral side into the blood. Na+ continues to be pumped into the blood maintaining the osmotic gradient allowing for continuous reabsorbtion of these molecules and ions. Terrestrial birds like the Corvus corax produce urine that is osmoltically more concentrated then its blood plasma. This is likely due to the fact that water is not as abundant in raven habitat. A key function of the Loop of Henle is to provide a large distance over which ions are transported out of the nephrons and since water will follow the transport of ions out of the nephrons, the Loop"
"start low in the cortex near the medulla and have a long loop of Henle which penetrates deeply into the renal medulla: only they have their loop of Henle surrounded by the vasa recta. These long loops of Henle and their associated vasa recta create a hyperosmolar gradient that allows for the generation of a concentrated urine. The nephron uses four mechanisms to convert blood into urine: filtration, reabsorption, secretion, and excretion of numerous substances. The structure and function of the epithelial cells lining the lumen change during the course of the nephron, and have segments named by their location"
"duct in the collecting duct system. Water present in the filtrate in the papillary duct flows through aquaporin channels out of the duct, moving passively down its concentration gradient. This process reabsorbs water and creates a concentrated urine for excretion. The loop of Henle can be divided into four parts: The tissue type of the loop is simple squamous epithelium. The ""thick"" and ""thin"" terminology does not refer to the size of the lumen, but to the size of the epithelial cells. The loop is also sometimes called the Nephron loop. The loop of Henle is supplied by blood in"
"into the medulla as the descending limb, and then returns to the cortex as the ascending limb to empty into the distal convoluted tubule. The primary role of the loop of Henle is to concentrate the salt in the interstitium, the tissue surrounding the loop. Considerable differences aid in distinguishing the descending and ascending limbs of the loop of Henle. The descending limb is permeable to water and noticeably less permeable to salt, and thus only indirectly contributes to the concentration of the interstitium. As the filtrate descends deeper into the hypertonic interstitium of the renal medulla, water flows freely"
"arranged in a ring around the cornea, near the scleral junction. They also are responsible for secreting mucin into tears. Crypts of Henle Crypts of Henle are microscopic pockets found in scattered sections of the conjunctiva around the eyeball. They are responsible for secreting mucin, a proteinous substance that makes up the inner layer of tears. It coats the cornea to provide a hydrophilic layer that allows for even distribution of the tear film. The layer of mucin allows tears to glide evenly across the eye’s surface. The crypts of Henle are named after German anatomist Friedrich Gustav Jakob Henle"
"of Henle is an important structure to insure minimal water lose out the ureters. Since not all nephrons of aves have the Loop of Henle, a birds ability to create a hypertonic filtrate can be more challenging then mammals. In response to dehydration birds release a hormone known as arginine vasotocin (AVT) into the blood. Among its roles AVT reduces the rate at which blood plasma filters out of the glomeruli and into the Bowman’s capsule. This reduces the total amount of water leaving the blood. Another function of AVT is its ability to increase permeability of the collecting ducts"
"not filtered through the glomerulus. This provides an oncotic pressure for ions to enter the vasa recta from the interstitium. The main function of the loop of Henle is to set up a concentration gradient. The descending loop of Henle receives isotonic (300 mOsm/L) fluid from the proximal convoluted tubule (PCT). The fluid is isotonic because as ions are reabsorbed by the gradient time system, water is also reabsorbed maintaining the osmolarity of the fluid in the PCT. Substances reabsorbed in the PCT include urea, water, potassium, sodium, chloride, glucose, amino acids, lactate, phosphate, and bicarbonate. Since water is also"
"of the loop of Henle, which makes the water reabsorb. By action of the urea transporter 2, some of this reabsorbed urea eventually flows back into the thin descending limb of the tubule, through the collecting ducts, and into the excreted urine. The body uses this mechanism, which is controlled by the antidiuretic hormone, to create hyperosmotic urine—i.e., urine with a higher concentration of dissolved substances than the blood plasma. This mechanism is important to prevent the loss of water, maintain blood pressure, and maintain a suitable concentration of sodium ions in the blood plasma. The equivalent nitrogen content (in"
"chloride concentration in neurons down to adult values. NKCC2 is specifically found in cells of the thick ascending limb of the loop of Henle and the macula densa in nephrons, the basic functional units of the kidney. Within these cells, NKCC2 resides in the apical membrane abutting the nephron's lumen, which is the hollow space containing urine. It thus serves both in sodium absorption and in tubuloglomerular feedback. The thick ascending limb of the loop of Henle begins at the deeper portion of the renal outer medulla. Here, the urine has a relatively high concentration of sodium. As urine moves"
"touches the arterioles of the glomerulus from which it rose. At this location, thick ascending limb of loop of Henle, there is a modified region of tubular epithelium called the Macula densa. Cells in the macula densa respond to changes in the sodium chloride levels in the distal tubule of the nephron via the tubuloglomerular feedback (TGF) loop. The macula densa's detection of elevated sodium chloride, which leads to a decrease in GFR, is based on the concept of purinergic signaling. An increase in the salt concentration causes several cell signals to eventually cause the adjacent afferent arteriole to constrict."
"and which reflects their different functions. The proximal tubule as a part of the nephron can be divided into an initial convoluted portion and a following straight (descending) portion. Fluid in the filtrate entering the proximal convoluted tubule is reabsorbed into the peritubular capillaries, including approximately two-thirds of the filtered salt and water and all filtered organic solutes (primarily glucose and amino acids). The loop of Henle is a U-shaped tube that extends from the proximal tubule. It consists of a descending limb and an ascending limb. It begins in the cortex, receiving filtrate from the proximal convoluted tubule, extends"
"into the renal tubules. Flow continues through the renal tubules, including the proximal tubule, the Loop of Henle, through the distal tubule and finally leaves the kidney by means of the collecting duct, leading to the renal pelvis, the dilated portion of the ureter. The renal medulla (Latin renes medulla = kidney middle) contains the structures of the nephrons responsible for maintaining the salt and water balance of the blood. These structures include the vasa rectae (both spuria and vera), the venulae rectae, the medullary capillary plexus, the loop of Henle, and the collecting tubule. The renal medulla is hypertonic"
"faithfully that of the small intestine. In vivo lineage tracing showed that LGR5 is expressed in nascent nephron cell cluster within the developing kidney. Specifically, the LGR5 stem cells contribute into the formation of the thick ascending limb of Henle’s loop and the distal convoluted tubule. However, expression is eventually truncated after postnatal day 7, a stark contrast to the facultative expression of LGR5 in actively renewing tissues such as in the intestines. The stomach lining also possess populations of LGR5 stem cells, although there are two conflicting theories: one is that LGR5 stem cells reside in the isthmus, the"
"the body. It differs from vertebrate blood in that it doesn't contain any red blood cells and therefore is without high oxygen carrying capacity, and is more similar to lymph found in vertebrates. Body fluids enter through one way valved ostia which are openings situated along the length of the combined aorta and heart organ. Pumping of the hemolymph occurs by waves of peristaltic contraction, originating at the body's posterior end, pumping forwards into the dorsal vessel, out via the aorta and then into the head where it flows out into the haemocoel. The hemolymph is circulated to the appendages"
"Van der Hoeven's organ Van der Hoeven's organ is the infrabuccal lamellar organ in the adult male ""Nautilus"" genus. It consists of a pair of fleshy narrow parallel lobes each containing 15-19 lamellae. It is analogous to Owen's laminated organ of the females, which is also infrabuccal and also lamellar, though females have an additional secondary sexual organ, the organ of Valenciennes. It along with the spadix and antispadix comprise the secondary sexual organs of the male. Its function has been described as possibly olfactory, but since its discovery in the mid nineteenth century its exact function, like that of"
"the collecting ducts descend through the medulla, they combine and empty their contents into the ureter. There are two types of avian nephrons, and nephrons become larger as depth from the kidney surface increases. Reptilian-type nephrons are the smallest nephrons, are found near a kidney’s surface, possess simple glomeruli, and do not have loops of Henle. Conversely, between 10% and 30% of the total nephron population is composed of mammalian-type nephrons, which are located in the innermost area of the kidney, have complex glomeruli, and contain loops of Henle. Once the kidneys receive blood, filtration of substances from the blood"
"convoluted section the proximal convoluted tubule followed by a straight section (proximal straight tubule); the loop of Henle, which has two parts, the descending loop of Henle (""descending loop"") and the ascending loop of Henle (""ascending loop""); the distal convoluted tubule (""distal loop""); the connecting tubule, and the collecting ducts. Nephrons have two lengths with different urine concentrating capacities: long juxtamedullary nephrons and short cortical nephrons. The four mechanisms used to create and process the filtrate (the result of which is to convert blood to urine) are filtration, reabsorption, secretion and excretion. Filtration occurs in the glomerulus and is largely"
"and increases in tonicity until it reaches its maximum at the bottom of the loop. This area represents the highest concentration in the nephron, but the collecting duct can reach this same tonicity with maximum ADH effect. The ascending limb of the loop of Henle receives an even lower volume of fluid and has different characteristics compared to the descending limb. In the ascending portion, the loop becomes impermeable to water and the cells of the loop actively reabsorb solutes from the luminal fluid; therefore water is not reabsorbed and ions are readily reabsorbed. As ions leave the lumen via"
"called a loop of Henle, which is present in the nephrons of birds and mammals. Because of this, many reptiles use the colon to aid in the reabsorption of water. Some are also able to take up water stored in the bladder. Excess salts are also excreted by nasal and lingual salt glands in some reptiles. Most reptiles are insectivorous or carnivorous and have simple and comparatively short digestive tracts due to meat being fairly simple to break down and digest. Digestion is slower than in mammals, reflecting their lower resting metabolism and their inability to divide and masticate their"
"of Henle in mammalian kidneys a Countercurrent multiplier and confirmed by laboratory findings in 1958 by Professor Carl W. Gottschalk. The theory was acknowledged a year later after a meticulous study showed that there is almost no osmotic difference between liquids on both sides of nephrons. Homer Smith, a considerable contemporary authority on renal physiology, opposed the model countercurrent concentration for 8 years, until conceding ground in 1959. Ever since, many similar mechanisms have been found in biologic systems, the most notable of these: the Rete mirabile in fish. In cold weather the blood flow to the limbs of birds"
"Renal hilum The renal hilum (Latin: ""hilum renale"") or renal pedicle is the hilum of the kidney, that is, its recessed central fissure where its vessels, nerves and ureter pass. The medial border of the kidney is concave in the center and convex toward either extremity; it is directed forward and a little downward. Its central part presents a deep longitudinal fissure, bounded by prominent overhanging anterior and posterior lips. This fissure is a hilum that transmits the vessels, nerves, and ureter. From anterior to posterior, the renal vein exits, the renal artery enters, and the renal pelvis exits the"
"the Na-K-2Cl symporter and the Na-H antiporter, the concentration becomes more and more hypotonic until it reaches approximately 100-150 mOsm/L. The ascending limb is also called the diluting segment of the nephron because of its ability to dilute the fluid in the loop from 1200 mOsm/L to 100 mOsm/L. Flow of the fluid through the entire loop of Henle is considered slow. As flow increases, the ability of the loop to maintain its osmolar gradient is reduced. The vasa recta (capillary loops) also have a slow flow as well. Increases in vasa recta flow wash away metabolites and cause the"
"a brush border (microvilli). DCT can be recognized by its numerous mitochondria, basal infoldings and lateral membrane interdigitations with neighboring cells. The point where DCT contacts the cortical thick ascending limb of the loop of Henle is called macula densa. It has tightly packed columnar cells which display reversed polarity and may monitor the osmolarity of blood. Histologically, cells of the DCT can be differentiated from cells of the proximal convoluted tubule: Distal convoluted tubule The distal convoluted tubule (DCT) is a portion of kidney nephron between the loop of Henle and the collecting tubule. It is partly responsible for"
"out of the descending limb by osmosis until the tonicity of the filtrate and interstitium equilibrate. The hypertonicity of the medulla (and therefore concentration of urine) is determined in part by the size of the loop of Henle. Unlike the descending limb, the thin ascending limb is impermeable to water, a critical feature of the countercurrent exchange mechanism employed by the loop. The ascending limb actively pumps sodium out of the filtrate, generating the hypertonic interstitium that drives countercurrent exchange. In passing through the ascending limb, the filtrate grows hypotonic since it has lost much of its sodium content. This"
"Renal pelvis The renal pelvis or pelvis of the kidney is the funnel-like dilated part of the ureter in the kidney. In humans, the renal pelvis is the point where the two or three major calyces join together. It has a mucous membrane is covered with transitional epithelium, and an underlying lamina propria of loose to dense connective tissue. The renal pelvis functions as a funnel for urine flowing to the ureter. The renal pelvis is the location of several kinds of kidney cancer and is affected by infection in pyelonephritis. The renal pelvis is the location of several kinds"
"thick ascending limb of the loop of Henle. Impaired sodium reabsorption increases diuresis by three mechanisms: Loop diuretics therefore ultimately result in decreased blood pressure. The hormone vasopressin, stimulates the activity of NKCC2. Vasopressin stimulates sodium chloride reabsorption in the thick ascending limb of the nephron by activating signaling pathways. Vasopressin increases the traffic of NKCC2 to the membrane and phosphorylates some serine and threonine sites on the cytoplasmic N-terminal of the NKCC2 located in the membrane, increasing its activity. Increased NKCC2 activity aids in water reabsorption in the collecting duct through aquaporin 2 channels by creating a hypo-osmotic filtrate."
"by hydrostatic pressure. The mesosome bears the lophophore, a specialist feeding structure which consists of a ring of up to 190 translucent tentacles arranged in a horseshoe-shape encircling the crescent-shaped mouth. The posterior and larger body section is the metasome and contains the metacoel. It is swollen at the base into an ampulla which may provide grip inside the tube. The gut is U-shaped and extends from the mouth to the ampulla before doubling back to the anus which is situated just below the mouth. The gonads are located in the metacoel. There are two blood vessels running along the"
"Thorax The thorax or chest (from the Greek θώραξ ""thorax"" ""breastplate, cuirass, corslet"" via ) is a part of the anatomy of humans and various other animals located between the neck and the abdomen. The thorax includes the thoracic cavity and the thoracic wall. It contains organs including the heart, lungs, and thymus gland, as well as muscles and various other internal structures. Many diseases may affect the chest, and one of the most common symptoms is chest pain. In humans and other hominids, the thorax is the chest region of the body between the neck and the abdomen, along"
"cases the sclerites are fused to various degrees. Thorax The thorax or chest (from the Greek θώραξ ""thorax"" ""breastplate, cuirass, corslet"" via ) is a part of the anatomy of humans and various other animals located between the neck and the abdomen. The thorax includes the thoracic cavity and the thoracic wall. It contains organs including the heart, lungs, and thymus gland, as well as muscles and various other internal structures. Many diseases may affect the chest, and one of the most common symptoms is chest pain. In humans and other hominids, the thorax is the chest region of the"
"ADH is released the aquaporins that are opened are also permeable to urea. This allows urea to leave the collecting duct into the medulla, creating a hyperosmotic solution that ""attracts"" water. Urea can then re-enter the nephron and be excreted or recycled again depending on whether ADH is still present or not. The 'single effect' describes the fact that the ascending thick limb of the loop of Henle is not permeable to water but is permeable to sodium chloride. This allows for a countercurrent exchange system whereby the medulla becomes increasingly concentrated, but at the same time setting up an"
"particular to the Romantic literature (19th century). The French word for the organ is ""rate"". The connection between ""spleen"" (the organ) and ""melancholy"" (the temperament) comes from the humoral medicine of the ancient Greeks. One of the humours (body fluid) was the black bile, secreted by the spleen organ and associated with melancholy. In eighteenth- and nineteenth-century England, women in bad humor were said to be afflicted by the spleen, or the vapours of the spleen. In modern English, ""to vent one's spleen"" means to vent one's anger, e.g. by shouting, and can be applied to both males and females."