Kidney Structure Diagram: Cortex, Medulla and Pelvis
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Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
Key diagram
A kidney cross-section shows three main regions: the outer cortex (containing glomeruli and convoluted tubules), the inner medulla (containing loops of Henle and collecting ducts) and the renal pelvis (where urine collects before entering the ureter).
The kidney cross-section diagram links the gross anatomy to the position of nephrons. Students must label each region, the blood supply and the ureter, and understand where ultrafiltration and reabsorption take place.
Drawing the cross-section
Draw a bean-shaped outline. Divide the interior into three zones. The outermost zone is the cortex: draw it as a darker band around the edge. The middle zone is the medulla: draw it with striations (lines) pointing inward, representing the loops of Henle and collecting ducts. The innermost space is the renal pelvis, a funnel-shaped area that collects urine and leads to the ureter.
Blood supply
Draw the renal artery entering the kidney at the hilum (the indented side): this brings oxygenated blood containing urea and other waste. Draw the renal vein leaving alongside it: this carries cleaned blood with less urea. The renal artery branches into smaller arterioles that supply the glomeruli in the cortex.
Where nephron parts are located
The glomeruli, Bowman's capsules and convoluted tubules are all in the cortex. The loops of Henle dip down into the medulla. The collecting ducts run through the medulla and empty into the renal pelvis. This explains why the cortex and medulla look different under the microscope.
Label checklist
Check these labels are present and correctly positioned before finishing your drawing.
✓Cortex
✓Medulla
✓Renal pelvis
✓Ureter
✓Renal artery
✓Renal vein
✓Hilum
Try a diagram question (2 marks)
On a diagram of the kidney, label the cortex and state what happens in this region. [2]
Show the answer and marking guidance
Cortex labelled on the outer region of the kidney.
Ultrafiltration occurs in the cortex at the glomerulus / Bowman's capsule, and selective reabsorption occurs in the convoluted tubules.
Original Cambridge-style practice written for this site.
Common diagram mistakes
Check these against your own drawing before moving on.
Swapping the cortex and medulla: the cortex is always the outer region.
Forgetting the renal pelvis in the centre.
Drawing the renal artery and vein on opposite sides: they both enter and leave at the hilum.