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Countercurrent Multiplication
A countercurrent mechanism system is a mechanism that expends energy to create a concentration gradient. It is found widely in nature and especially in mammalian organs. For example, it can refer to the process that is underlying the process of urine concentration, that is, the production of hyperosmotic urine by the mammalian kidney. The ability to concentrate urine is also present in birds. Countercurrent multiplication is frequently mistaken for countercurrent exchange, a similar but different mechanism where gradients are maintained, but not established. Physiological principles The term derives from the form and function of the loop of Henle, which consists of two parallel limbs of renal tubules running in opposite directions, separated by the interstitial space of the renal medulla. * The descending limb of the loop of Henle is permeable to water but impermeable to solutes, due to the presence of aquaporin 1 in its tubular wall. Thus, water moves across the tubular wall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concentration Gradient
Molecular diffusion, often simply called diffusion, is the thermal motion of all (liquid or gas) particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size (mass) of the particles. Diffusion explains the net flux of molecules from a region of higher concentration to one of lower concentration. Once the concentrations are equal the molecules continue to move, but since there is no concentration gradient the process of molecular diffusion has ceased and is instead governed by the process of self-diffusion, originating from the random motion of the molecules. The result of diffusion is a gradual mixing of material such that the distribution of molecules is uniform. Since the molecules are still in motion, but an equilibrium has been established, the result of molecular diffusion is called a "dynamic equilibrium". In a phase with uniform temperature, absent external net forces acting on the particles, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquaporin
Aquaporins, also called water channels, are channel proteins from a larger family of major intrinsic proteins that form pores in the membrane of biological cells, mainly facilitating transport of water between cells. The cell membranes of a variety of different bacteria, fungi, animal and plant cells contain aquaporins through which water can flow more rapidly into and out of the cell than by diffusing through the phospholipid bilayer. Aquaporins have six membrane-spanning alpha helical domains with both carboxylic and amino terminals on the cytoplasmic side. Two hydrophobic loops contain conserved asparagine- proline-alanine ("NPA motif") which form a barrel surrounding a central pore-like region that contains additional protein density. Because aquaporins are usually always open and are prevalent in just about every cell type, this leads to a misconception that water readily passes through the cell membrane down its concentration gradient. Water can pass through the cell m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Liverpool
, mottoeng = These days of peace foster learning , established = 1881 – University College Liverpool1884 – affiliated to the federal Victoria Universityhttp://www.legislation.gov.uk/ukla/2004/4 University of Manchester Act 2004. legislation.gov.uk (4 July 2011). Retrieved on 14 September 2011.1903 – royal charter , type = Public , endowment = £190.2 million (2020) , budget = £597.4 million (2020–21) , city = Liverpool , country = England , campus = Urban , coor = , chancellor = Colm Tóibín , vice_chancellor = Dame Janet Beer , head_label = Visitor , head = The Lord President of the Council '' ex officio'' , students = () , undergrad = () , postgrad = () , colours = The University , affiliations = Russell Group, EUA, N8 Group, NWUA, AACSB, AMBA, EQUIS, EASN, Universities UK , website = , logo = Unive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Werner Kuhn (chemist)
Werner Kuhn (February 6, 1899 – August 27, 1963) was a Swiss physical chemist who developed the first model of the viscosity of polymer solutions using statistical mechanics.Werner Kuhn - Encyclopædia Britannica He is known for being the first to apply : : to the modeling of rubber molecules, i.e. the "rubber band entropy model", s which he imagi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl W
Carl may refer to: * Carl, Georgia, city in USA * Carl, West Virginia, an unincorporated community *Carl (name), includes info about the name, variations of the name, and a list of people with the name * Carl², a TV series * "Carl", an episode of television series ''Aqua Teen Hunger Force'' * An informal nickname for a student or alum of Carleton College CARL may refer to: * Canadian Association of Research Libraries * Colorado Alliance of Research Libraries See also * Carle (other) * Charles *Carle, a surname * Karl (other) *Karle (other) Karle may refer to: Places * Karle (Svitavy District), a municipality and village in the Czech Republic * Karli, India, a town in Maharashtra, India ** Karla Caves, a complex of Buddhist cave shrines * Karle, Belgaum, a settlement in Belgaum di ... {{disambig ja:カール zh:卡尔 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interstitial Fluid
In cell biology, extracellular fluid (ECF) denotes all body fluid outside the cells of any multicellular organism. Total body water in healthy adults is about 60% (range 45 to 75%) of total body weight; women and the obese typically have a lower percentage than lean men. Extracellular fluid makes up about one-third of body fluid, the remaining two-thirds is intracellular fluid within cells. The main component of the extracellular fluid is the interstitial fluid that surrounds cells. Extracellular fluid is the internal environment of all multicellular animals, and in those animals with a blood circulatory system, a proportion of this fluid is blood plasma. Plasma and interstitial fluid are the two components that make up at least 97% of the ECF. Lymph makes up a small percentage of the interstitial fluid. The remaining small portion of the ECF includes the transcellular fluid (about 2.5%). The ECF can also be seen as having two components – plasma and lymph as a delivery syst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osmotic
Osmosis (, ) is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region of high water potential (region of lower solute concentration) to a region of low water potential (region of higher solute concentration), in the direction that tends to equalize the solute concentrations on the two sides. It may also be used to describe a physical process in which any solvent moves across a selectively permeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations. Osmosis can be made to do work. Osmotic pressure is defined as the external pressure required to be applied so that there is no net movement of solvent across the membrane. Osmotic pressure is a colligative property, meaning that the osmotic pressure depends on the molar concentration of the solute but not on its identity. Osmosis is a vital process in biological systems, as biological membranes are semipe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Transport
In cellular biology, ''active transport'' is the movement of molecules or ions across a cell membrane from a region of lower concentration to a region of higher concentration—against the concentration gradient. Active transport requires cellular energy to achieve this movement. There are two types of active transport: primary active transport that uses adenosine triphosphate ( ATP), and secondary active transport that uses an electrochemical gradient. Some examples of active transport include: * Phagocytosis of bacteria by macrophages * Movement of calcium ions out of cardiac muscle cells * Transportation of amino acids across the intestinal lining in the human gut * Secretion of proteins such as enzymes, peptide hormones, and antibodies from various cells * Functioning of white blood cells to defend invading diseases Active cellular transportation (ACT) Unlike passive transport, which uses the kinetic energy and natural entropy of molecules moving down a gradient, activ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interstitium
The interstitium is a contiguous fluid-filled space existing between a structural barrier, such as a cell membrane or the skin, and internal structures, such as organs, including muscles and the circulatory system. The fluid in this space is called interstitial fluid, comprises water and solutes, and drains into the lymph system. The interstitial compartment is composed of connective and supporting tissues within the body – called the extracellular matrix – that are situated outside the blood and lymphatic vessels and the parenchyma of organs. Structure The non-fluid parts of the interstitium are predominantly collagen types I, III, and V, elastin, and glycosaminoglycans, such as hyaluronan and proteoglycans that are cross-linked to form a honeycomb-like reticulum. Such structural components exist both for the general interstitium of the body, and within individual organs, such as the myocardial interstitium of the heart, the renal interstitium of the kidn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquaporin 1
Aquaporin 1 (AQP-1) is a protein that in humans is encoded by the ''AQP1'' gene. AQP-1 is a widely expressed water channel, whose physiological function has been most thoroughly characterized in the kidney. It is found in the basolateral and apical plasma membranes of the proximal tubules, the descending limb of the loop of Henle, and in the descending portion of the vasa recta. Additionally, it is found in red blood cells, vascular endothelium, the gastrointestinal tract, sweat glands, lungs, and the central nervous system. Neural AQP-1 receptors are regulated by vasopressin AVPR1A receptor activity. Function Aquaporins are a family of small integral membrane proteins related to the major intrinsic protein ( MIP or AQP0). This gene encodes an aquaporin which functions as both a molecular water channel protein and as a non-selective cation channel gated by cyclic guanosine monophosphate (cGMP). It is a homotetramer with six bilayer spanning domains and N-glycosylation s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urine
Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellular metabolism generates many by-products that are rich in nitrogen and must be cleared from the bloodstream, such as urea, uric acid, and creatinine. These by-products are expelled from the body during urination, which is the primary method for excreting water-soluble chemicals from the body. A urinalysis can detect nitrogenous wastes of the mammalian body. Urine plays an important role in the earth's nitrogen cycle. In balanced ecosystems, urine fertilizes the soil and thus helps plants to grow. Therefore, urine can be used as a fertilizer. Some animals use it to mark their territories. Historically, aged or fermented urine (known as lant) was also used for gunpowder production, household cleaning, tanning of leather and dyeing of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Renal Medulla
The renal medulla is the innermost part of the kidney. The renal medulla is split up into a number of sections, known as the renal pyramids. Blood enters into the kidney via the renal artery, which then splits up to form the segmental arteries which then branch to form interlobar arteries. The interlobar arteries each in turn branch into arcuate arteries, which in turn branch to form interlobular arteries, and these finally reach the glomeruli. At the glomerulus the blood reaches a highly disfavourable pressure gradient and a large exchange surface area, which forces the serum portion of the blood out of the vessel and 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: ''medulla renis'' 'marrow of the kidney') contains the structures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
