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Diagram showing the basic physiologic mechanisms of the kidney. The kidney's ability to perform many of its functions depends on the three fundamental functions of filtration, reabsorption, and secretion, whose sum is called renal clearance or renal excretion.
The formation of urine begins within the functional unit of the kidney, the nephrons. Urine then flows through the nephrons, through a system of converging tubules called collecting ducts. These collecting ducts then join together to form the minor calyces, followed by the major calyces that ultimately join the renal pelvis. From here, urine ...
The formation of urine takes place in microscopic structures called nephrons, about one million of which are found in a normal human kidney. Blood enters the kidney though the renal artery and flows through the kidney's vasculature into the glomerulus , a tangled knot of capillaries surrounded by Bowman's capsule .
Average urine production in adult humans is around 1.4 L (0.31 imp gal; 0.37 US gal) of urine per person per day with a normal range of 0.6 to 2.6 L (0.13 to 0.57 imp gal; 0.16 to 0.69 US gal) per person per day, produced in around 6 to 8 urinations per day depending on state of hydration, activity level, environmental factors, weight, and the ...
The rate therefore measured is the quantity of the substance in the urine that originated from a calculable volume of blood. Relating this principle to the below equation – for the substance used, the product of urine concentration and urine flow equals the mass of substance excreted during the time that urine has been collected.
In other words, the allantois takes no share in its formation. After the separation of the rectum from the dorsal part of the cloaca, the ventral part becomes the primary urogenital sinus. [2] The urogenital sinus, in turn, divides into the superficial definitive urogenital sinus and the deeper anterior vesico-urethral portion.
Urination is the release of urine from the bladder to the outside of the body. Urine is released through the urethra and exits the penis or vulva through the urinary meatus in placental mammals, [1] [2]: 38, 364 but is released through the cloaca in other vertebrates. [3] [1] It is the urinary system's form of excretion.
The most common type of cast, hyaline casts are solidified Tamm–Horsfall mucoprotein secreted from the tubular epithelial cells of individual nephrons. Low urine flow, concentrated urine, or an acidic environment can contribute to the formation of hyaline casts, and as such, they may be seen in normal individuals in dehydration or vigorous exercise.