BiologyICSE Class 10 · Excretory System

Structure of a Nephron and the Malpighian Capsule (ICSE Class 10 Biology)

Updated 16 October 2026 · Fact-checked

A nephron is the structural and functional unit of the kidney. It begins with the Malpighian capsule, a cup-shaped Bowman's capsule holding a capillary knot, the glomerulus. The wider afferent arteriole brings blood in and the narrower efferent arteriole takes it out. The tubule continues as the proximal tubule, loop of Henle and distal tubule into a collecting duct.

Understand Structure of a Nephron and the Malpighian Capsule

The working unit. Each kidney has about a million microscopic tubules called nephrons (kidney tubules). A nephron is the structural and functional unit of the kidney: each one filters blood and makes a little urine. The syllabus asks for 'a general idea of the structure', with emphasis on the Malpighian capsule.

Parts of a nephron, in order.

Part	Where in the kidney	Description
Bowman's capsule	cortex	double-walled cup at the blind start of the tubule
Glomerulus	cortex	knot of capillaries inside the cup
Proximal convoluted tubule (PCT)	cortex	first coiled part; most reabsorption
Loop of Henle	dips into the medulla	U-shaped loop; helps reabsorb water
Distal convoluted tubule (DCT)	cortex	second coiled part
Collecting duct	cortex to medulla	receives many nephrons; opens into the pelvis

Malpighian capsule (renal corpuscle) = Bowman's capsule + glomerulus. It is the site of ultrafiltration.

Blood supply of a nephron.

Afferent arteriole, a branch of the renal artery, enters the glomerulus; it is wider.
Efferent arteriole leaves the glomerulus; it is narrower.
Because blood enters by a wide vessel and leaves by a narrow one, pressure builds up in the glomerulus, forcing fluid out into Bowman's capsule.
The efferent arteriole then breaks into peritubular capillaries around the tubule; these take back reabsorbed substances and join to form branches of the renal vein.

Note the unusual pattern: blood flows arteriole → capillaries → arteriole → capillaries before entering a vein.

How the structure suits the job.

Glomerular capillary walls and the inner wall of Bowman's capsule are very thin: an easy filter.
Wide-in, narrow-out arterioles give the high pressure needed for filtration.
The long, coiled tubule with its capillary network gives a large surface and time for reabsorption.

Nephron versus neuron (2025 asked the difference).

Nephron	Neuron
unit of the kidney (excretory system)	unit of the nervous system
filters blood and forms urine	carries nerve impulses
tubule with a capillary knot	cell body with dendrites and axon

Flow chart: blood and filtrate. Renal artery → afferent arteriole (wide) → glomerulus → efferent arteriole (narrow) → peritubular capillaries → renal vein. Filtrate: Bowman's capsule → PCT → loop of Henle → DCT → collecting duct → pelvis → ureter.

Draw-and-label checklist: Malpighian capsule. A cup (Bowman's capsule) drawn with two walls; a coiled capillary knot (glomerulus) inside; a thick afferent arteriole entering and a visibly thinner efferent arteriole leaving from the same side; the tubule starting from the opposite side; arrows for blood flow. Labels: afferent arteriole, efferent arteriole, glomerulus, Bowman's capsule, beginning of renal tubule, glomerular filtrate.

Draw-and-label checklist: nephron. Malpighian capsule; coiled PCT; U-shaped loop of Henle; coiled DCT opening into a collecting duct; peritubular capillaries around the tubule. Mark 'cortex' and 'medulla' if asked.

Structure of a Nephron and the Malpighian Capsule: key facts

Parts of a nephron: Bowman's capsule
Glomerulus
Proximal convoluted tubule
Loop of Henle
Distal convoluted tubule
Collecting duct; In this order from the start.
Malpighian capsule and arterioles: $M a l p i g hian c a p s u l e = B o w ma n^{'} sc a p s u l e + g l o m er u l u s ∣ A f f er e n t a r t er i o l e : w i d er, b r in g s b l oo d in ∣ E f f er e n t a r t er i o l e : na r r o w er, t ak es b l oo d o u t$; Wide in, narrow out = high pressure.
Blood route through a nephron: Renal artery
Afferent arteriole
Glomerulus
Efferent arteriole
Peritubular capillaries
Renal vein; Two capillary beds in a row.

How to answer Structure of a Nephron and the Malpighian Capsule questions

ICSE asks you to draw or label a Malpighian capsule or nephron, differentiate the afferent and efferent arterioles, define the nephron, order its parts, or compare it with a neuron.

1For arterioles, compare the same feature: diameter (afferent wide, efferent narrow) and direction (in, out).
2In diagrams, make the afferent arteriole clearly thicker.
3Order the tubule: capsule, PCT, loop of Henle, DCT, collecting duct.
4When defining a nephron, write 'structural and functional unit of the kidney'.
5Link structure to function: high pressure for filtration, long tubule for reabsorption.

Structure of a Nephron and the Malpighian Capsule in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Coffee filter with a pump

Suppose a café uses a machine that forces hot water through ground coffee at high pressure, and the coffee comes out quickly while the grounds stay behind.

Compare this with the Malpighian capsule.

Try it first, then show the solutionSolution

In the machine, pressure pushes liquid through a fine filter; large grounds stay back.
In the glomerulus, the wide afferent and narrow efferent arterioles raise blood pressure.
Water and small molecules are pushed through the thin capillary walls into Bowman's capsule.
Blood cells and proteins, like the grounds, are too large and stay in the blood.

Answer: Both are pressure filters: high pressure forces small molecules through, leaving large ones behind.

Memory hook: Glomerulus = pressure filter.

Garden hose and nozzle

Suppose you partly block the end of a garden hose with your thumb. Water squirts out of the small leaks along the hose much harder.

Relate this to the efferent arteriole.

Try it first, then show the solutionSolution

Narrowing the outlet raises pressure inside the hose.
The efferent arteriole is narrower than the afferent, so it acts like the thumb.
Pressure rises inside the glomerulus.
Fluid is forced out through the thin capillary walls, like water from the leaks.

Answer: The narrow efferent arteriole raises pressure in the glomerulus, driving ultrafiltration.

Memory hook: Narrow exit, high pressure.

Tricks to remember Structure of a Nephron and the Malpighian Capsule

Short memory aids. Say each one aloud once, then use it on a question the same day.

Afferent = Arrives, Efferent = Exits
A for Arrives (and wide like an Avenue); E for Exits (and narrow like an Entry-gate).
Use it when: Direction and diameter of the arterioles.
B-G-P-L-D-C
'Big Girls Play Long Distance Cricket': Bowman's, Glomerulus, PCT, Loop, DCT, Collecting duct.
Use it when: Order of nephron parts.
Malpighian = Mug with a ball
Bowman's capsule is the mug; the glomerulus is the ball of wool inside.
Use it when: Drawing the capsule.

Structure of a Nephron and the Malpighian Capsule: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: The capillary knot · 1 mark · MCQBoard level

The knot of capillaries inside Bowman's capsule is called the:
(a) loop of Henle (b) glomerulus (c) collecting duct (d) pelvis

Try it first, then show the solutionSolution

The capillary knot in the cup is the glomerulus.

Answer: (b) glomerulus.

Example 2: Two arterioles · 2 marks · Short answerBoard level

A student labels both arterioles at a glomerulus as the same size. State the correct difference in their diameters and why it matters. (The 2024 paper asked this difference.)

Try it first, then show the solutionSolution

The afferent arteriole is wider; the efferent arteriole is narrower (1 mark).
This builds up high pressure in the glomerulus, which drives ultrafiltration (1 mark).

Answer: Afferent wide, efferent narrow; creates high pressure for ultrafiltration.

Example 3: Tracing a dye · 2 marks · Short answerHarder board level

A harmless dye that is filtered but not reabsorbed is injected into the renal artery. Trace its path until it leaves the kidney, naming each blood vessel and each part of the nephron it passes through.

Try it first, then show the solutionSolution

Renal artery → afferent arteriole → glomerulus, where it is filtered into Bowman's capsule (1 mark).
Bowman's capsule → proximal convoluted tubule → loop of Henle → distal convoluted tubule → collecting duct → pelvis → ureter (1 mark).

Answer: Renal artery → afferent arteriole → glomerulus → Bowman's capsule → PCT → loop of Henle → DCT → collecting duct → pelvis → ureter.

Example 4: Two capillary beds · 2 marks · Short answerHarder board level

Blood in a nephron passes through two capillary networks before it reaches a vein. Name the two networks and the vessel joining them, and state the job of each network.

Try it first, then show the solutionSolution

Glomerulus → efferent arteriole → peritubular capillaries (1 mark).
Glomerulus: ultrafiltration of blood into Bowman's capsule; peritubular capillaries: take back substances reabsorbed from the tubule (1 mark).

Answer: Glomerulus (filtration) and peritubular capillaries (take back reabsorbed substances), joined by the efferent arteriole.

Example 5: Filtrate volume · 3 marks · Case-basedHOTS / competency

Suppose the two kidneys together filter blood at 125 mL per minute. (a) How many litres of filtrate are formed in a day? (b) If 1.5 L of urine is passed in that day, what percentage of the filtrate was reabsorbed? (c) Which part of the nephron makes this huge filtration possible?

Try it first, then show the solutionSolution

(a) 125 × 60 × 24 = 180 000 mL = 180 L (1 mark).
(b) (180 − 1.5) ÷ 180 × 100 ≈ 99.17% (1 mark).
(c) The Malpighian capsule (glomerulus with Bowman's capsule), where high pressure forces fluid out (1 mark).

Answer: (a) 180 L. (b) About 99.2%. (c) Malpighian capsule.

Example 6: A leaky filter · 3 marks · Short answerHOTS / competency

Suppose years of very high blood pressure damage a person's glomerular capillaries so that their walls become leaky. (a) Which substance, normally absent, may then appear in his urine? (b) Explain why. (c) Why does most of it still reach the urine even though the filtrate passes along the whole tubule?

Try it first, then show the solutionSolution

(a) Protein (plasma proteins such as albumin) (1 mark).
(b) Normally proteins are too large to pass the glomerular walls; leaky walls let them into Bowman's capsule with the filtrate (1 mark).
(c) Selective reabsorption returns mainly small useful substances such as glucose, amino acids, water and salts; the tubule cannot take back large amounts of protein, so it passes on into urine (1 mark).

Answer: (a) Protein. (b) Damaged walls let large protein molecules into the filtrate. (c) The tubule cannot reabsorb large amounts of protein, so it is passed out.

Where students lose marks in Structure of a Nephron and the Malpighian Capsule

The slips examiners see most often, and what to write instead.

Mistake: Arteriole diameters reversed
CISCE examiners' comments (2024): candidates wrote narrow for the afferent arteriole and wide for the efferent arteriole.
Do this: Afferent: wide, in. Efferent: narrow, out.
Usually costs: 1-2 marks.
Mistake: Equal-width arterioles in a diagram
Drawing both vessels alike hides the key feature of the Malpighian capsule.
Do this: Draw the afferent arteriole clearly thicker.
Usually costs: 1 mark.
Mistake: Calling the kidney the 'unit'
Students write 'kidney is the unit of excretion'; the unit within the kidney is the nephron.
Do this: Nephron = structural and functional unit of the kidney.
Usually costs: 1 mark.

Exam tips

Malpighian capsule = Bowman's capsule + glomerulus.
Afferent wide, efferent narrow.
Order: capsule, PCT, loop of Henle, DCT, collecting duct.
Nephron: kidney; neuron: nervous system.

Practice questions on Structure of a Nephron and the Malpighian Capsule

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
The Malpighian capsule consists of:
(a) glomerulus and loop of Henle (b) Bowman's capsule and glomerulus (c) PCT and DCT (d) collecting duct and pelvis
Hint
Cup plus knot.
Answer
(b).
Q2 · 1 mark · Very short answerBoard level
Name the structural and functional unit of the kidney.
Hint
About a million per kidney.
Answer
Nephron (kidney tubule).
Q3 · 1 mark · Assertion-reasonHarder board level
Assertion (A): Pressure of blood in the glomerulus is high.
Reason (R): The efferent arteriole is narrower than the afferent arteriole.
(a) (A) is true and (R) is false.
(b) (A) is false and (R) is true.
(c) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(d) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
Hint
Narrow exit.
Answer
(c).
Q4 · 2 marks · Short answerHarder board level
Bowman's capsule is a double-walled cup. Which wall lies in close contact with the glomerulus, and name three substances that pass across it into the capsule.
Hint
The filter is between the knot and the cup.
Answer
The inner (thin) wall. Any three of: water, glucose, amino acids, salts, urea.
Q5 · 2 marks · Short answerHarder board level
Name the part of the nephron that (a) lies in the medulla as a U-shaped tube; (b) receives urine from many nephrons.
Hint
Loop; duct.
Answer
(a) Loop of Henle (b) Collecting duct.
Q6 · 2 marks · Short answerHarder board level
State two features of the Malpighian capsule that suit it for filtration.
Hint
Walls and pressure.
Answer
Very thin walls of glomerular capillaries and Bowman's capsule; high blood pressure in the glomerulus because the afferent arteriole is wider than the efferent (also a large capillary surface).
Q7 · 2 marks · Short answerHarder board level
In which region of the kidney are the Malpighian capsules found, and why does that region look granular?
Hint
Outer region.
Answer
In the cortex; the many tiny Malpighian capsules and coiled tubules packed there give it a granular, dotted look.
Q8 · 3 marks · Case-basedHOTS / competency
Read and answer.
Suppose a person has about 1 million nephrons in each kidney, and a long illness destroys 75% of the nephrons in both kidneys.
(a) How many working nephrons remain in total? (1)
(b) Why may urea build up in his blood although he still passes urine? (1)
(c) Which blood vessel brings urea to each kidney? (1)
Hint
Two kidneys; 25% remain.
Answer
(a) 2 000 000 × 25 ÷ 100 = 500 000. (b) Fewer nephrons filter less blood each day, so urea is removed more slowly than it is formed. (c) Renal artery.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.What is the glomerulus?Show answer
A knot of capillaries inside Bowman's capsule.
2.Which arteriole is wider?Show answer
Afferent arteriole.
3.Where are Malpighian capsules located?Show answer
In the cortex of the kidney.
4.Into what does the collecting duct open?Show answer
The pelvis of the kidney.
5.Which vessel forms the peritubular capillaries?Show answer
Efferent arteriole.

Structure of a Nephron and the Malpighian Capsule: frequently asked questions

Is the renal corpuscle the same as the Malpighian capsule?

Yes. Both terms mean Bowman's capsule with its glomerulus.

Do I need the vasa recta or juxtaglomerular apparatus?

No. ICSE Class 10 needs only a general idea of the nephron's structure.

How many nephrons are there?

About a million in each kidney.

Why is the nephron called a functional unit?

Each nephron can carry out every step of urine formation by itself.