Kidney Structure (Cambridge (CIE) A Level Biology): Revision Note

Exam code: 9700

Emma Archbold

Written by: Emma Archbold

Reviewed by: Alistair Marjot

Updated on

Structure of the human kidney

  • Humans have two kidneys

  • The kidneys are responsible for carrying out two very important functions:

    • As an osmoregulatory organthey regulate the water content of the blood (vital for maintaining blood pressure)

    • As an excretory organthey excrete the toxic waste products of metabolism (such as urea) and substances in excess of requirements (such as salts)

Diagram of the human urinary system showing kidneys, renal artery, vein, ureter, bladder, and urethra with labelled functions and blood flow.
The position of the kidneys and their associated structures

Structure

Function

Renal artery

Carries oxygenated blood (containing urea and salts) to the kidneys

Renal vein

Carries deoxygenated blood (that has had urea and excess salts removed) away from the kidneys

Kidney

Regulates water content of blood and filters blood

Ureter

Carries urine from the kidneys to the bladder

Bladder

Stores urine (temporarily)

Urethra

Releases urine outside of the body

  • The kidney itself is surrounded by a fairly tough outer layer known as the fibrous capsule

  • Beneath the fibrous capsule, the kidney has three main areas:

    • The cortex (contains the glomerulus, Bowman’s capsule, proximal convoluted tubule, and distal convoluted tubule of the nephrons)

    • The medulla (contains the loop of Henle and collecting duct of the nephrons)

    • The renal pelvis (where the ureter joins the kidney)

Diagram of a kidney cross-section showing labelled parts: cortex, medulla, fibrous capsule, renal pelvis, ureter, renal vein and artery branches.
A cross-section of a kidney (as seen when cut in half vertically)

Examiner Tips and Tricks

Make sure you can identify all the structures mentioned on this page if you are presented with a diagram of the kidney and its associated structures, or a diagram with a vertical cross-section of the kidney itself.

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Emma Archbold

Author: Emma Archbold

Expertise: Biology Content Creator

Prior to working at SME, Emma was a Biology teacher for 5 years. During those years she taught three different GCSE exam boards and two A-Level exam boards, gaining a wide range of teaching expertise in the subject. Emma particularly enjoys learning about ecology and conservation. Emma is passionate about making her students achieve the highest possible grades in their exams by creating amazing revision resources!

Alistair Marjot

Reviewer: Alistair Marjot

Expertise: Environmental Systems and Societies & Biology Content Creator

Alistair graduated from Oxford University with a degree in Biological Sciences. He has taught GCSE/IGCSE Biology, as well as Biology and Environmental Systems & Societies for the International Baccalaureate Diploma Programme. While teaching in Oxford, Alistair completed his MA Education as Head of Department for Environmental Systems & Societies. Alistair has continued to pursue his interests in ecology and environmental science, recently gaining an MSc in Wildlife Biology & Conservation with Edinburgh Napier University.