Nephron Diagram IGCSE Biology 0610

Nephron Diagram: Filtration and Reabsorption

Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.

Key diagram

The nephron is the functional unit of the kidney. Blood is filtered at the glomerulus into Bowman's capsule (ultrafiltration), and useful substances are reabsorbed in the proximal convoluted tubule. The remaining fluid becomes urine.

The nephron diagram is an Extended tier favourite. Students must label each part, describe ultrafiltration and selective reabsorption, and explain how the composition of the filtrate changes along the nephron.

Drawing the nephron structure

Start with a cup-shaped structure for Bowman's capsule. Inside it, draw a tight ball of capillaries for the glomerulus. From the capsule, draw a coiled tube for the proximal convoluted tubule, then a U-shaped loop for the loop of Henle, followed by another coiled section for the distal convoluted tubule, ending in a straight collecting duct.

Show the afferent arteriole (wider) entering the glomerulus and the efferent arteriole (narrower) leaving it. Draw a capillary network wrapping around the tubules.

Ultrafiltration at the glomerulus

Blood enters the glomerulus at high pressure because the afferent arteriole is wider than the efferent arteriole, creating a pressure difference. Small molecules: water, glucose, urea, ions: are forced out of the blood through the capillary walls and into Bowman's capsule. Large molecules like proteins and blood cells are too big to pass through and remain in the blood. This process is called ultrafiltration.

Selective reabsorption in the tubules

In the proximal convoluted tubule, all glucose is reabsorbed back into the blood by active transport. Most water, amino acids and useful ions are also reabsorbed. The tubule wall has microvilli to increase surface area and many mitochondria to provide energy for active transport. Urea is only partially reabsorbed, and its concentration increases along the tubule.

In the loop of Henle and collecting duct, water reabsorption is controlled by the hormone ADH to regulate the concentration of urine.

Formation of urine

By the end of the collecting duct, the filtrate has become urine, containing water, urea and excess ions. No glucose or amino acids should be present in healthy urine. The urine drains into the renal pelvis, then through the ureter to the bladder.

Label checklist

Check these labels are present and correctly positioned before finishing your drawing.

✓ Bowman's capsule
✓ Glomerulus
✓ Afferent arteriole
✓ Efferent arteriole
✓ Proximal convoluted tubule
✓ Loop of Henle
✓ Distal convoluted tubule
✓ Collecting duct

Try a diagram question (4 marks)

Explain how the structure of the glomerulus and Bowman's capsule is adapted for ultrafiltration. [4]

Show the answer and marking guidance

The afferent arteriole is wider than the efferent arteriole, creating high blood pressure in the glomerulus.
The high pressure forces small molecules (water, glucose, urea, ions) out of the blood.
The capillary walls and Bowman's capsule wall act as a filter, allowing small molecules through.
Large molecules such as proteins and blood cells are too large to pass through and remain in the blood.

Original Cambridge-style practice written for this site.

Common diagram mistakes

Check these against your own drawing before moving on.

Drawing the afferent and efferent arterioles the same width.
Stating that proteins are filtered out of the blood: they are too large.
Forgetting that glucose is fully reabsorbed and should not appear in urine.
Confusing filtration (at the glomerulus) with reabsorption (in the tubules).
Not labelling the loop of Henle.