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Kidneys
In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood exits into the paired renal veins. Each kidney is attached to a ureter, a tube that carries excreted urine to the bladder. The kidney participates in the control of the volume of various body fluids, fluid osmolality, acid-base balance, various electrolyte concentrations, and removal of toxins. Filtration occurs in the glomerulus: one-fifth of the blood volume that enters the kidneys is filtered. Examples of substances reabsorbed are solute-free water, sodium, bicarbonate, glucose, and amino acids. Examples of substances secreted are hydrogen, ammonium, potassium and uric acid. The nephron is the structural and functi ...
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Mammalian Kidney
The mammalian kidneys are a pair of excretory organs of the urinary system of mammals, being functioning Kidney (vertebrates), kidneys in postnatal-to-adult individuals (i. e. Kidney (vertebrates)#Metanephros, metanephric kidneys). The kidneys in mammals are usually bean-shaped or externally lobulated. They are located behind the peritoneum (Retroperitoneal space, retroperitoneally) on the back (Dorsal (anatomy), dorsal) wall of the body. The typical mammalian kidney consists of a renal capsule, a peripheral Renal cortex, cortex, an internal Renal medulla, medulla, one or more Renal calyx, renal calyces, and a renal pelvis. Although the calyces or renal pelvis may be absent in some species. The medulla is made up of one or more renal pyramids, forming papillae with their innermost parts. Generally, urine produced by the cortex and medulla drains from the papillae into the calyces, and then into the renal pelvis, from which urine exits the kidney through the ureter. Nitrogen-contain ...
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Ureter
The ureters are tubes composed of smooth muscle that transport urine from the kidneys to the urinary bladder. In an adult human, the ureters typically measure 20 to 30 centimeters in length and about 3 to 4 millimeters in diameter. They are lined with urothelial cells, a form of transitional epithelium, and feature an extra layer of smooth muscle in the lower third to aid in peristalsis. The ureters can be affected by a number of diseases, including urinary tract infections and kidney stone. is when a ureter is narrowed, due to for example chronic inflammation. Congenital abnormalities that affect the ureters can include the development of two ureters on the same side or abnormally placed ureters. Additionally, reflux of urine from the bladder back up the ureters is a condition commonly seen in children. The ureters have been identified for at least two thousand years, with the word "ureter" stemming from the stem relating to urinating and seen in written records since at ...
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Vitamin D
Vitamin D is a group of structurally related, fat-soluble compounds responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, along with numerous other biological functions. In humans, the most important compounds within this group are vitamin D3 ( cholecalciferol) and vitamin D2 ( ergocalciferol). Unlike the other twelve vitamins, vitamin D is only conditionally essential, as with adequate skin exposure to the ultraviolet B (UVB) radiation component of sunlight there is synthesis of cholecalciferol in the lower layers of the skin's epidermis. For most people, skin synthesis contributes more than diet sources. Vitamin D can also be obtained through diet, food fortification and dietary supplements. In the U.S., cow's milk and plant-based milk substitutes are fortified with vitamin D3, as are many breakfast cereals. Government dietary recommendations typically assume that all of a person's vitamin D is taken by mouth, given the potential for ...
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Renal Artery
The renal arteries are paired arteries that supply the kidneys with blood. Each is directed across the crus of the diaphragm, so as to form nearly a right angle. The renal arteries carry a large portion of total blood flow to the kidneys. Up to a third of total cardiac output can pass through the renal arteries to be filtered by the kidneys. Structure The renal arteries normally arise at a 90° angle off of the left interior side of the abdominal aorta, immediately below the superior mesenteric artery. They have a radius of approximately 0.25  cm, 0.26 cm at the root. The measured mean diameter can differ depending on the imaging method used. For example, the diameter was found to be 5.04 ± 0.74 mm using ultrasound but 5.68 ± 1.19 mm using angiography. Due to the anatomical position of the aorta, the inferior vena cava, and the kidneys, the right renal artery is normally longer than the left renal artery. * The right passes behind the inferior vena cava, ...
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Urinary System
The human urinary system, also known as the urinary tract or renal system, consists of the kidneys, ureters, urinary bladder, bladder, and the urethra. The purpose of the urinary system is to eliminate waste from the body, regulate blood volume and blood pressure, control levels of Electrolyte, electrolytes and Metabolite, metabolites, and regulate Acid–base homeostasis, blood pH. The urinary tract is the body's drainage system for the eventual removal of urine. The kidneys have an extensive blood supply via the Renal artery, renal arteries which leave the kidneys via the renal vein. Each kidney consists of functional units called nephrons. Following filtration of blood and further processing, waste (in the form of urine) exits the kidney via the ureters, tubes made of smooth muscle fibres that propel urine towards the urinary bladder, where it is stored and subsequently expelled through the urethra during urination. The female and male urinary system are very similar, differin ...
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Renal Vein
The renal veins in the renal circulation, are large-calibre veins that drain blood filtered by the kidneys into the inferior vena cava. There is one renal vein draining each kidney. Each renal vein is formed by the convergence of the interlobar veins of one kidney. Because the inferior vena cava is on the right half of the body, the left renal vein is longer than the right one. Structure One renal vein drains each kidney. A renal vein is situated anterior to its corresponding accompanying renal artery. The renal veins empty into the inferior vena cava, entering it at nearly a 90° angle. Due to the right-ward displacement of the inferior vena cava from the midline, the left renal vein is some 3 times longer than the right one (~7.5 cm and ~2.5 cm, respectively). The renal vein divides into 4 divisions upon entering the kidney: * the anterior branch which receives blood from the anterior portion of the kidney and, * the posterior branch which receives blood from the posterior ...
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Urinary Bladder
The bladder () is a hollow organ in humans and other vertebrates that stores urine from the Kidney (vertebrates), kidneys. In placental mammals, urine enters the bladder via the ureters and exits via the urethra during urination. In humans, the bladder is a distensible organ that sits on the pelvic floor. The typical adult human bladder will hold between 300 and (10 and ) before the urge to empty occurs, but can hold considerably more. The Latin phrase for "urinary bladder" is ''vesica urinaria'', and the term ''vesical'' or prefix ''vesico-'' appear in connection with associated structures such as vesical veins. The modern Latin word for "bladder" – ''cystis'' – appears in associated terms such as cystitis (inflammation of the bladder). Structure In humans, the bladder is a hollow muscular organ situated at the base of the pelvis. In gross anatomy, the bladder can be divided into a broad (base), a body, an apex, and a neck. The apex (also called the vertex) is directed ...
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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 ...
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Endocrine System
The endocrine system is a messenger system in an organism comprising feedback loops of hormones that are released by internal glands directly into the circulatory system and that target and regulate distant Organ (biology), organs. In vertebrates, the hypothalamus is the neural control center for all endocrine systems. In humans, the major endocrine glands are the thyroid gland, thyroid, parathyroid gland, parathyroid, pituitary gland, pituitary, pineal gland, pineal, and adrenal glands, and the (male) testis and (female) ovaries. The hypothalamus, pancreas, and thymus also function as endocrine glands, among other functions. (The hypothalamus and pituitary glands are organs of the Neuroendocrinology#Neuroendocrine system, neuroendocrine system. One of the most important functions of the hypothalamusit is located in the brain adjacent to the pituitary glandis to link the endocrine system to the nervous system via the pituitary gland.) Other organs, such as the kidneys, also have ...
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Potassium
Potassium is a chemical element; it has Symbol (chemistry), symbol K (from Neo-Latin ) and atomic number19. It is a silvery white metal that is soft enough to easily cut with a knife. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals, all of which have a single valence electron in the outer electron shell, which is easily removed to create cation, an ion with a positive charge (which combines with anions to form salts). In nature, potassium occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac-flame color, colored flame. It is found dissolved in seawater (which is 0.04% potassium by weight), and occurs in many minerals such as orthoclase, a ...
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