describe the structure of the human kidney, limited to: fibrous capsule, cortex, medulla, renal pelvis, ureter, branches of the renal artery and renal vein
Cambridge A-Level Biology – Homeostasis in Mammals: The Human Kidney
Homeostasis in Mammals – The Human Kidney
Learning Objective
Describe the structure of the human kidney, focusing on the fibrous capsule, cortex, medulla, renal pelvis, ureter, and the main branches of the renal artery and renal vein.
Key Structural Components
Fibrous Capsule – A tough, collagen‑rich outer covering that protects the kidney and maintains its shape.
Cortex – The outer layer of renal tissue beneath the capsule; contains the renal corpuscles (glomeruli and Bowman's capsules) and the proximal and distal convoluted tubules.
Medulla – The inner region composed of renal pyramids; each pyramid contains loops of Henle and collecting ducts that concentrate urine.
Renal Pelvis – A funnel‑shaped cavity that collects urine from the collecting ducts and channels it into the ureter.
Ureter – A muscular tube that transports urine from the renal pelvis to the urinary bladder.
Vascular Supply
Renal Artery
Enters the kidney at the hilum.
Divides into segmental branches (anterior and posterior).
Each segmental branch further divides into interlobar arteries that run between the renal pyramids.
Interlobar arteries become arcuate arteries at the corticomedullary junction.
Arcuate arteries give rise to cortical radiate (interlobular) arteries supplying the cortex.
Renal \cdot ein
Collects blood from the cortical radiate veins.
These converge into arcuate veins, then interlobar veins, and finally form the renal vein that exits at the hilum.
Summary Table
Structure
Location
Primary Function in Homeostasis
Fibrous Capsule
Outer surface of kidney
Protects renal tissue; maintains internal pressure for filtration.
Cortex
Just beneath the capsule
Site of glomerular filtration and tubular re‑absorption of nutrients, ions, and water.
Medulla
Central region, contains renal pyramids
Creates osmotic gradient to concentrate urine and conserve water.
Renal Pelvis
Central funnel at the renal hilum
Collects urine from collecting ducts and directs it to the ureter.
Ureter
Extends from renal pelvis to bladder
Transports urine away from the kidney, preventing back‑flow.
Drains de‑oxygenated blood after filtration; helps maintain blood pressure.
Suggested diagram: Cross‑section of a human kidney showing the fibrous capsule, cortex, medulla (renal pyramids), renal pelvis, ureter, and the branching pattern of the renal artery and vein.