Mammoth Memory

Tubular secretion

Although the glomerulus transfers many of the substances from the blood to the tubule, other transfers of substances from the blood vessels (the peritubular capillaries) to the tubule take place further along to regulate the pH level (acidity/alkalinity) in the blood.

 Detailed annotated diagram of the filtration structure of the nephron

Here is a simple overview of secretion and absorption in the nephron.


 Simplified diagram showing the re-absorption and secretion of blood into the tubule

In the glomerulus, substances are filtered out of the blood. The peritubular capillaries reabsorb substances that the body wants to retain. At the same time, the peritubular capillaries secrete substances into the tubule to regulate pH level.

A memory aid to remember secretion is where blood re enters the tubule 

Do you ever hear tuba players practise? No, they always do it in secret (tubular secretion).

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