A day of filtrate, balanced
"A day of filtrate, balanced" is a free, interactive Class 11 Biology simulation for NEET, built on the lesson "Reabsorption and secretion" in Excretory Products and their Elimination. Meher's kidneys make 125 mL of filtrate a minute, 180 L a day. Move the slider and watch how much of it would leave as urine, in one-litre bottles. GFR 125 mL/min × 1440 min = 180 L a day. With about 1.5 L of urine, the tubules must reabsorb nearly 99 per cent of the filtrate.
From the lesson Reabsorption and secretion in Excretory Products and their Elimination. Change the values and watch what happens.
The idea behind it
NCERT §16.2
- About 180 litres of filtrate are formed a day but only about 1.5 litres of urine are passed, so nearly 99 per cent of the filtrate must be taken back by the renal tubules. This is reabsorption.
- The epithelial cells of the different tubule segments reabsorb by active or passive mechanisms.
- Glucose, amino acids, Na⁺ and similar substances are reabsorbed actively; nitrogenous wastes are absorbed passively.
- In the initial segments of the nephron, water is also reabsorbed passively.
- In secretion, tubular cells add substances such as H⁺, K⁺ and ammonia to the filtrate.
- Secretion is an important step too, because it keeps the ionic and acid–base balance of the body fluids.
Questions
2 answers
- What does the "A day of filtrate, balanced" simulation show?
- Meher's kidneys make 125 mL of filtrate a minute, 180 L a day. Move the slider and watch how much of it would leave as urine, in one-litre bottles.
- Is this simulation free?
- Yes. It is free and runs in the browser on a phone or a laptop. It belongs to the lesson "Reabsorption and secretion" in Excretory Products and their Elimination (Class 11 Biology).
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