NEET UG · Biology · chapter
Human Physiology for NEET: where the questions actually come from
Human Physiology questions in NEET come to roughly eight to twelve of the ninety Biology questions, and most of them test a definition, a number or a sequence stated plainly in NCERT rather than anything you have to reason out. This guide gives the unit’s six chapters, the figures worth memorising, the five mistakes that cost the most marks, a free quiz and worked examples. BrainStride is an AI tutor for JEE, NEET and Olympiad preparation that runs a 20-minute diagnostic, maps your weak chapters and writes a daily plan, with every solution checked by teachers.
Quick answer
- Human Physiology carries about 8–12 of the 90 NEET Biology questions in recent papers — our estimate from past papers, not an official figure.
- The unit has six chapters in the current NEET syllabus: breathing, body fluids and circulation, excretion, locomotion, neural control and chemical coordination.
- Most questions are recall with one step of application, so the marks sit in NCERT’s exact numbers — lung volumes, cardiac output, filtration rate, resting potential.
- The commonest losses are definitional: lung capacities stated loosely, ECG waves matched to the wrong cardiac event, reabsorption placed in the wrong part of the nephron.
Human Physiology at a glance
Questions per paper
8–12
Of 90 Biology questions · BrainStride analysis of past papers
Chapters in the unit
6
All Class 11, all in the Zoology half by convention
Question style
Recall + application
Definitions, numbers and sequences from NCERT
Marks at stake
Up to 48
At +4 each, before negative marking
Questions per year
- 20199 Q
- 202010 Q
- 20219 Q
- 202211 Q
- 202310 Q
- 20249 Q
- 202511 Q
- 202610 Q
BrainStride analysis of past papers
Key concepts
Breathing and exchange of gases
Respiratory organs and the mechanism of breathing, then the part NEET returns to every year: lung volumes and capacities by definition, and how oxygen and carbon dioxide are carried. Learn the four volumes and the capacities built from them as arithmetic, not as a list.
Body fluids and circulation
Blood and lymph, the human heart, the cardiac cycle and its 0.8-second timing, the ECG and double circulation. Questions usually ask which event a wave or a sound belongs to, or turn stroke volume and heart rate into cardiac output.
Excretory products and their elimination
The nephron, urine formation and the counter-current mechanism. The high-value facts are quantitative: how much blood is filtered, how much filtrate forms, how much is reabsorbed and where each substance is reclaimed along the tubule.
Locomotion and movement
Muscle structure and the sliding filament theory, then the skeleton and joints. The sliding filament question is nearly always about which bands change during contraction and which do not.
Neural control and coordination
The neuron, resting and action potentials, impulse conduction and the synapse, then the central neural system and reflex action. Ion movements are the pinch point: which ion moves which way, and which pump maintains the resting state.
Chemical coordination and integration
Endocrine glands, their hormones and the disorders of excess and deficiency. This is pure matching, and it is where a table beats paragraphs — gland, hormone, target, disorder, in four columns.
How NEET asks physiology
Statements to judge true or false, matching pairs, and single-step numericals on cardiac output or filtration. Almost nothing needs derivation, which is why an imprecise definition costs the same four marks as a concept you never studied.
Formulas to know cold
Cardiac output
CO = stroke volume × heart rate
About 70 mL × 72 per minute ≈ 5 L per minute in a healthy adult.
Vital capacity
VC = IRV + TV + ERV
The maximum volume you can breathe out after a forced inspiration. Residual volume is not part of it.
Total lung capacity
TLC = VC + RV
Roughly 5,800 mL. Residual volume cannot be exhaled, so it appears only here.
Inspiratory and functional residual capacity
IC = TV + IRV · FRC = ERV + RV
Both are built by addition — derive them rather than memorising four separate numbers.
Oxygen transport
≈97% by haemoglobin · ≈3% dissolved in plasma
Oxygen binds haemoglobin as oxyhaemoglobin; only a small fraction travels dissolved.
Carbon dioxide transport
≈70% as bicarbonate · 20–25% as carbamino-haemoglobin · ≈7% dissolved
Carbonic anhydrase in red blood cells drives the bicarbonate route.
Gas delivery per 100 mL of blood
≈5 mL O₂ to tissues · ≈4 mL CO₂ to alveoli
At rest this works out to about 250 mL of oxygen delivered per minute.
Glomerular filtration rate
GFR ≈ 125 mL per minute ≈ 180 L per day
The kidneys filter about 1,100–1,200 mL of blood per minute to produce it.
Urine output
≈1.5 L per day from 180 L of filtrate
More than 99 per cent of the filtrate is reabsorbed — a favourite one-line question.
Cardiac cycle
0.8 s per cycle at 72 beats per minute
P wave: atrial depolarisation. QRS: ventricular depolarisation. T wave: ventricular repolarisation.
Resting membrane potential
≈ −70 mV · pump ratio 3 Na⁺ out : 2 K⁺ in
Depolarisation is sodium moving in; repolarisation is potassium moving out.
Sliding filament theory
A band constant · I band and H zone shorten
The filaments slide; they do not contract. The sarcomere shortens because the overlap increases.
Where marks leak in this chapter
Lung capacities stated loosely
Why it happens
The four volumes are learnt as a list of numbers, so the capacities built from them get mixed up under time pressure.The fix
Write the four volumes once, then derive IC, EC, FRC, VC and TLC by addition. Check that residual volume appears in FRC and TLC but never in vital capacity.ECG waves matched to the wrong event
Why it happens
The cardiac cycle and the ECG are studied as two separate diagrams instead of one timeline.The fix
Draw the cycle and the trace on the same line: P before atrial systole, QRS at the start of ventricular systole, T at the end of it.Reabsorption placed in the wrong part of the nephron
Why it happens
Urine formation is remembered as three stages rather than as a route with a job at each segment.The fix
Walk the tubule in order and name what leaves at each point — proximal tubule for the bulk of water and electrolytes, loop for the concentration gradient, distal and collecting duct for fine control.Sliding filament described without the bands
Why it happens
The theory is recalled as "filaments slide", which answers no question actually set.The fix
Learn the three band changes as one sentence: A band unchanged, I band shortens, H zone narrows, so the sarcomere shortens.Hormones matched to the wrong gland or disorder
Why it happens
Hormones are revised gland by gland, but questions ask across glands — a hormone here, a disorder there.The fix
Keep one table with gland, hormone, target and the disorders of excess and deficiency, and revise it by column as well as by row.Check yourself
6 questions
Question 1
Which combination gives vital capacity?
Question 2
A person has a stroke volume of 70 mL and a heart rate of 72 beats per minute. What is the cardiac output?
Question 3
The QRS complex of an ECG represents:
Question 4
Most of the carbon dioxide in blood is transported as:
Question 5
During muscle contraction, which of these does NOT shorten?
Question 6
The glomerular filtration rate in a healthy adult is about:
Solved examples
Single-step numerical · body fluids
A person has a stroke volume of 80 mL and a heart rate of 75 beats per minute. How many times does a blood volume of 5 litres circulate through the heart in one minute?
- Cardiac output = stroke volume × heart rate = 80 mL × 75 = 6,000 mL per minute.
- Convert: 6,000 mL = 6 litres per minute.
- Compare with the total blood volume: 6 L ÷ 5 L = 1.2.
Answer: The whole blood volume passes through the heart about 1.2 times every minute.
Assertion and reason · breathing
Assertion: subtracting the expiratory reserve volume from vital capacity leaves the inspiratory capacity. Reason: inspiratory capacity is tidal volume plus inspiratory reserve volume.
- Write vital capacity in full: VC = IRV + TV + ERV.
- Subtract ERV from both sides: VC − ERV = IRV + TV.
- Compare with the definition of inspiratory capacity: IC = TV + IRV, which is the same quantity.
Answer: Both statements are true, and the reason is the correct explanation — the subtraction works precisely because IC is defined as TV + IRV.
Two-step numerical · gas transport
Every 100 mL of oxygenated blood delivers about 5 mL of oxygen to the tissues. At a cardiac output of 5 litres per minute, how much oxygen reaches the tissues each minute?
- Convert the cardiac output to millilitres: 5 L = 5,000 mL per minute.
- Count the 100 mL portions: 5,000 ÷ 100 = 50.
- Multiply by the oxygen delivered per portion: 50 × 5 mL = 250 mL.
Answer: About 250 mL of oxygen is delivered to the tissues per minute, the figure NCERT quotes for a resting adult.
Human Physiology: common questions
How many questions come from Human Physiology in NEET?
In recent NEET papers, Human Physiology has carried roughly 8 to 12 of the 90 Biology questions. That is BrainStride’s analysis of past papers, not an official figure — NTA publishes no chapter-wise weightage for NEET UG. Treat it as a reason to finish the unit early, not as a promise about any one paper.
Which chapters are in the Human Physiology unit for NEET?
The current NEET syllabus lists six chapters in this unit: Breathing and Exchange of Gases, Body Fluids and Circulation, Excretory Products and their Elimination, Locomotion and Movement, Neural Control and Coordination, and Chemical Coordination and Integration. Confirm the unit against the official syllabus on neet.nta.nic.in before you plan around it.
Is NCERT enough for Human Physiology in NEET?
For this unit, largely yes. Most questions test a definition, a number or a sequence stated in NCERT, so the work is reading it closely rather than reading more books. What NCERT will not give you is repetition under time — that comes from previous-year questions and timed practice on the same six chapters.
Which part of Human Physiology gives the most trouble?
Body fluids and circulation, because it mixes definitions with a timeline. Students can recite the cardiac cycle and still match the QRS complex to the wrong event, or know stroke volume without converting it to cardiac output. Practising the cycle, the ECG and the numbers together fixes most of the loss.
How should I revise Human Physiology in the last month?
Revise by table rather than by chapter: one table of lung volumes and capacities, one of cardiac cycle events against ECG waves, one of nephron segments against what each reabsorbs, and one of glands, hormones and disorders. Then attempt mixed questions across all six chapters, because that is how the paper asks them.
Does Human Physiology overlap with Class 12 Biology?
It supports it. Human Physiology is Class 11, but Human Reproduction, Human Health and Disease, and parts of Biotechnology assume you already know circulation, excretion and hormonal control. Students who leave this unit for the end usually end up revising it twice anyway, so it is cheaper to finish it first.
Six chapters, and the paper asks them in one breath.
The 20-minute diagnostic checks Human Physiology against the rest of Biology and names the two units to fix first. Free, no card.