The outer layer of the kidney where the Bowman's capsules are found is the?

Step 1: Analyze the question The question asks for the outer layer of the kidney, which is where the Bowman's capsules are located.

Step 2: Explain the concept A kidney has three main regions when you cut it lengthwise:

• Cortex: the outer layer. It contains the Bowman's capsules, the glomeruli, and the convoluted tubules (proximal and distal). This is where ultrafiltration takes place.
• Medulla: the inner region beneath the cortex. It contains the loops of Henle and the collecting ducts. It is arranged into cone-shaped structures called pyramids.
• Pelvis: the funnel-shaped cavity in the innermost part. It collects urine from the collecting ducts and passes it into the ureter.

Step 3: Solution by elimination

• A. Cortex: outer layer, houses the Bowman's capsules. ✔
• B. Pelvis: the inner cavity that collects urine, so it is not the outer layer. ✘
• C. Medulla: the inner region, containing the loops of Henle and collecting ducts. ✘
• D. Pyramid: a structure within the medulla. ✘

Step 4: Answer The outer layer of the kidney containing the Bowman's capsules is the cortex, which is option A.

Exam tip: Remember "Cortex = Covers the outside". Also remember that filtration (Bowman's capsule) happens in the cortex, while water concentration (loop of Henle) happens in the medulla. Going from the outside in, the order is Cortex → Medulla → Pelvis → Ureter.