Urine Formation

Urine Formation - Glomerular Filtration

• The first step of urine formation is glomerular filtration
• Takes place in the renal corpsule when fluid is forced out of blood & is collected by glomerular capsule
• Efferent arteriole narrows increasing resistance to blood flow and increasing pressure in glomerulus
• Blood and other components are forced through the membrane & into the capsule
• A fluid called filtrate is left
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• Caption: Glomerular Filtration

Urine Formation - Reabsorption

• The next process is called reabsorption
• Selective reabsorption of the filtrate takes place in the renal tubule
• During selective reabsorption, water, glucose, amino acids, ions and wastes like urea are absorped
• The large surface area of the long length of the kidney tubule allows for effective reabsorption
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Urine Formation - Tubular Secretion

• Whereas selective absorption removes substances from filtrate into the blood, tubular secretion adds to the filtrate from the blood
• To raise the pH of the blood, the tubules secrete hydrogen and ammonium ions into the filtrate
• The now produced urine drains into the ureters and stored in the urinary bladder