7.3.3Unit 6: Practical Skills in Biology II
The Kidney: Structure — IAL Edexcel Linear Revision Notes & Topical Questions
5 min read 4 parts Lesson 30 of 48 Unit quiz
Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
Part 1 of 4Functions and Gross Structure
Osmoregulation
- Osmoregulation The kidneys regulate the water content of the blood, which supports blood pressure and prevents osmotic damage to cells.
Excretion
- Excretion They remove nitrogenous waste such as urea and excess salts from the blood in urine.
Fibrous capsule
- Fibrous capsule A tough outer layer that surrounds and protects each kidney.
Cortex
- Cortex The outer region containing the filtering units and the convoluted tubules.
Medulla
- Medulla The inner region that contains the loops of Henle and collecting ducts.
Renal pelvis
- Renal pelvis The funnel-shaped cavity that collects urine and leads to the ureter.
Part 2 of 4The Nephron
The Nephron
In the cortex
- In the cortex The glomerulus, Bowman's capsule, proximal convoluted tubule and distal convoluted tubule lie here.
In the medulla
- In the medulla The loop of Henle and the collecting duct lie here, and the collecting duct drains into the renal pelvis.
Cortical nephrons
- Cortical nephrons They have short loops of Henle that barely enter the medulla and make up the majority of nephrons.
Juxtamedullary nephrons
- Juxtamedullary nephrons These have long loops of Henle reaching deep into the medulla and are important for conserving water.
| Region | Parts of nephron found |
|---|---|
| Cortex | Bowman's capsule, glomerulus, PCT, DCT |
| Medulla | Loop of Henle, collecting duct |
| Renal pelvis | Collects urine from all ducts |
Part 3 of 4Blood Supply
1
Blood enters the kidney through the renal artery, which branches into many afferent arterioles.
2
Each afferent arteriole supplies a knot of capillaries called the glomerulus, located inside a Bowman's capsule.
3
The capillaries of the glomerulus rejoin to form the efferent arteriole, which is narrower than the afferent arteriole.
4
The efferent arteriole divides into a capillary network around the proximal and distal tubules and the loop of Henle.
5
These capillaries join to form the renal vein, which carries blood away from the kidney.
Part 4 of 4Exam Checklist & Tips
7.3.3 – Key Points for the Exam
- Nephron The microscopic functional unit of the kidney that forms urine.
- Cortex The outer region of the kidney containing the glomeruli.
- Medulla The inner region containing the loops of Henle.
- Afferent arteriole The vessel that carries blood to the glomerulus.
- Efferent arteriole The narrower vessel that carries blood away from the glomerulus.
Common Mistakes
- Saying the loop of Henle is in the cortex; it is in the medulla.
- Mixing the afferent and efferent arterioles; the afferent is wider and brings blood in.
- Calling the ureter the tube from the bladder to the outside; it links kidney to bladder.
- Placing the glomerulus in the renal pelvis.
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