Normal renal structure and function

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Normal renal structure and function

Anatomy:
Basic functional unit is the nephron, which has four regions:
1) Glomerulus
2) Proximal convoluted tubule
3) Loop of Henle
4) Distal convoluted tubule
Nephrons are orientated with the upper part of the loop of Henle is in the renal cortex and the lower end is in the renal medulla.

Collecting ducts -

Physiology:
Filtration:
• occurs at glomerulus
• first step in urine formation
• all small molecules (eg electrolytes, amino acids, glucose, drugs) are filtered – larger molecule stay in blood
• non-selective process – not regulated
• produces up to 125ml of filtrate per minute

Reabsorption:
• >99% of water, nutrients and electrolytes that are filtered at glomerulus are reabsorbed
• solutes (eg amino acids, glucose) are reabsorbed by active transport
• water is reabsorbed by osmotic processes created by the reabsorbed nutrients

Tubular secretion:
• active secretion of molecules

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