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Efferent Arterioles
The efferent arterioles are blood vessels that are part of the urinary tract of organisms. Efferent (from Latin ex + ferre) means "outgoing", in this case meaning carrying blood out away from the glomerulus. The efferent arterioles form a convergence of the capillaries of the glomerulus, and carry blood away from the glomerulus that has already been filtered. They play an important role in maintaining the glomerular filtration rate despite fluctuations in blood pressure. In the mammalian kidney, they follow two markedly different courses, depending on the location of the glomeruli from which they arise. In the mammalian kidney, about 15% of glomeruli lie close to the boundary between the renal cortex and renal medulla and are known as juxtamedullary glomeruli. The rest are simply undifferentiated cortical glomeruli. In undifferentiated cortical glomeruli The efferent arterioles of the undifferentiated cortical glomeruli are the most complex. Promptly on leaving the glomerulus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Renal Tubule
The nephron is the minute or microscopic structural and functional unit of the kidney. It is composed of a renal corpuscle and a renal tubule. The renal corpuscle consists of a tuft of capillaries called a glomerulus and a cup-shaped structure called Bowman's capsule. The renal tubule extends from the capsule. The capsule and tubule are connected and are composed of epithelial cells with a lumen. A healthy adult has 1 to 1.5 million nephrons in each kidney. Blood is filtered as it passes through three layers: the endothelial cells of the capillary wall, its basement membrane, and between the podocyte foot processes of the lining of the capsule. The tubule has adjacent peritubular capillaries that run between the descending and ascending portions of the tubule. As the fluid from the capsule flows down into the tubule, it is processed by the epithelial cells lining the tubule: water is reabsorbed and substances are exchanged (some are added, others are removed); first with the in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plexus
In anatomy, a plexus (from the Latin term for 'braid') is a branching network of blood vessels, lymphatic vessels, or nerves. The nerves are typically axons outside the central nervous system. The standard plural form in English is plexuses. Alternatively, the Latin plural plexūs may be used. Types Nerve plexuses The four primary nerve plexuses are the cervical plexus, brachial plexus, lumbar plexus, and the sacral plexus. Cardiac plexus Celiac plexus Renal plexus Venous plexus Choroid plexus The choroid plexus is a part of the central nervous system in the brain and consists of capillaries, brain ventricles, and ependymal cells. Invertebrates The plexus is the characteristic form of nervous system in the coelenterates and persists with modifications in the flatworms. The nerves of the radially symmetric echinoderms also take this form, where a plexus underlies the ectoderm of these animals and deeper in the body other nerve cells form plexuses of limited extent. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vasoconstriction
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in controlling hemorrhage and reducing acute blood loss. When blood vessels constrict, the flow of blood is restricted or decreased, thus retaining body heat or increasing vascular resistance. This makes the skin turn paler because less blood reaches the surface, reducing the radiation of heat. On a larger level, vasoconstriction is one mechanism by which the body regulates and maintains mean arterial pressure. Medications causing vasoconstriction, also known as vasoconstrictors, are one type of medicine used to raise blood pressure. Generalized vasoconstriction usually results in an increase in systemic blood pressure, but it may also occur in specific tissues, causing a localized reduction in b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angiotensin
Angiotensin is a peptide hormone that causes vasoconstriction and an increase in blood pressure. It is part of the renin–angiotensin system, which regulates blood pressure. Angiotensin also stimulates the release of aldosterone from the adrenal cortex to promote sodium retention by the kidneys. An oligopeptide, angiotensin is a hormone and a dipsogen. It is derived from the precursor molecule angiotensinogen, a serum globulin produced in the liver. Angiotensin was isolated in the late 1930s (first named "angiotonin" or "hypertensin", later renamed "angiotensin" as a consensus by the 2 groups that independently discovered it) and subsequently characterized and synthesized by groups at the Cleveland Clinic and Ciba laboratories. Precursor and types Angiotensinogen Angiotensinogen is an α-2-globulin synthesized in the liver and is a precursor for angiotensin, but has also been indicated as having many other roles not related to angiotensin peptides. It is a member ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Cells
Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cell and the vertebrate's principal means of delivering oxygen () to the body tissues—via blood flow through the circulatory system. Erythrocytes take up oxygen in the lungs, or in fish the gills, and release it into tissues while squeezing through the body's capillaries. The cytoplasm of a red blood cell is rich in hemoglobin (Hb), an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells and the blood. Each human red blood cell contains approximately 270 million hemoglobin molecules. The cell membrane is composed of proteins and lipids, and this structure provides properties essential for physiological cell function such as deformability and stability of the blood cell while traversing t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fermentation (biochemistry)
Fermentation is a type of anaerobic metabolism which harnesses the redox potential of the reactants to make adenosine triphosphate (ATP) and organic end products. Organic molecules, such as glucose or other sugars, are catabolized and reduced by donating their electrons to other organic molecules (cofactors, coenzymes, etc.). Fermentation is important in several areas of human society. Humans have used fermentation in the production and preservation of food for 13,000 years. It has been associated with health benefits, unique flavor profiles, and making products have better texture. Humans and their livestock also benefit from fermentation from the microbes in the gut that release end products that are subsequently used by the host for energy. Perhaps the most commonly known use for fermentation is at an industrial level to produce commodity chemicals, such as ethanol and lactate. Ethanol is used in a variety of alcoholic beverages (beers, wine, and spirits) while lactate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urine
Urine is a liquid by-product of metabolism in humans and many other animals. In placental mammals, urine flows from the Kidney (vertebrates), kidneys through the ureters to the urinary bladder and exits the urethra through the penile meatus (males) or urethral meatus of the vulva (females) during urination. In other vertebrates, urine is excreted through the cloaca. Urine contains water-soluble by-products of Cell (biology), cellular metabolism that are rich in nitrogen and must be clearance (medicine), cleared from the Circulatory system, bloodstream, such as urea, uric acid and creatinine. 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, Reuse of excreta, urine can be used as a fertilizer. Some animals use it to territory (animal)#Scent marking, mark their territories. Historically, aged or fermented urine (kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonicity
In chemical biology, tonicity is a measure of the effective osmotic pressure gradient; the water potential of two Solution (chemistry), solutions separated by a Semipermeable membrane, partially-permeable cell Cell membrane, membrane. Tonicity depends on the relative concentration of selective membrane-impermeable solutes across a cell membrane which determine the direction and extent of osmotic flux. It is commonly used when describing the swelling-versus-shrinking response of cell (biology), cells immersed in an external solution. Unlike osmotic pressure, tonicity is influenced only by solutes that cannot cross the membrane, as only these exert an effective osmotic pressure. Solutes able to freely cross the membrane do not affect tonicity because they will always equilibrate with equal concentrations on both sides of the membrane without net solvent movement. It is also a factor affecting imbibition. There are three classifications of tonicity that one solution can have rela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rete Mirabile
A rete mirabile (Latin for "wonderful net"; : retia mirabilia) is a complex of arteries and veins lying very close to each other, found in some vertebrates, mainly warm-blooded ones. The rete mirabile utilizes countercurrent blood flow within the net (blood flowing in opposite directions) to act as a countercurrent exchanger. It exchanges heat, ions, or gases between vessel walls so that the two bloodstreams within the rete maintain a gradient with respect to temperature, or concentration of gases or solutes. This term was coined by Galen. Effectiveness The effectiveness of retia is primarily determined by how readily the heat, ions, or gases can be exchanged. For a given length, they are most effective with respect to gases or heat, then small ions, and decreasingly so with respect to other substances. The retia can provide for extremely efficient exchanges. In bluefin tuna, for example, nearly all of the metabolic heat in the venous blood is transferred to the arterial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Venulae Recti
The vasa recta of the kidney, (vasa recta renis) are the straight arterioles, and the straight venules of the kidney, – a series of blood vessels in the blood supply of the kidney that enter the medulla as the straight arterioles, and leave the medulla to ascend to the cortex as the straight venules. (Latin: ''vās'', "vessel"; ''rēctus'', "straight"). They lie parallel to the loop of Henle. These vessels branch off the efferent arterioles of juxtamedullary nephrons (those nephrons closest to the medulla). They enter the medulla, and surround the loop of Henle. Whereas the peritubular capillaries surround the cortical parts of the tubules, the vasa recta go into the medulla and are closer to the loop of Henle, and leave to ascend to the cortex. Terminations of the vasa recta form the straight venules, branches from the plexuses at the apices of the medullary pyramids. They run outward in a straight course between the tubes of the medullary substance and join the interlobul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
