The Human Body — Systems in Simple Words
✨ IN SHORT — THE WHOLE LESSON IN 20 SECONDS
Your body is 9 machine-teams: bones give shape, muscles move, heart-blood carries, lungs breathe, brain controls. Exam questions love numbers: 206 bones, heart beats ~72/min, normal temperature 37°C.
1. Bones, Muscles & Blood
Adult skeleton: 206 bones (babies ~300, many fuse). Longest bone: femur (thigh). Smallest: stapes (ear). Heart: 4 chambers, beats ~72/minute, pumps blood; normal BP 120/80 mmHg. Blood: RBC carries oxygen (haemoglobin, red), WBC fights germs (soldiers), Platelets clot wounds. Blood groups: O− is universal donor, AB+ universal receiver.
📌 RBC lifespan ~120 days; made in bone marrow. Total blood in adult ≈ 5 litres.
2. Organs & Their Jobs (one-line map)
Liver = largest internal organ, makes bile, stores glucose (glycogen), cleans blood. Kidneys = filter blood → urine (functional unit: nephron). Lungs = exchange O₂/CO₂ (units: alveoli). Brain = control centre (largest part: cerebrum). Small intestine = digestion completes + absorption (villi increase surface). Skin = largest organ overall.
💡 Trick: 'L-L' — Liver is Largest inside; skin is Largest overall. Examiners twist exactly this.
3. Vitamins & Deficiency (high-yield table)
A → night blindness (carrot, papaya). B1 → beri-beri. C → scurvy (amla, lemon — C for Citrus). D → rickets (sunlight vitamin). K → blood clotting help. Iron lack → anaemia. Iodine lack → goitre (thyroid). Protein lack in children → kwashiorkor/marasmus.
📌 'A-C-D-K' fat-soluble vitamins — they store in fat; B & C are water-soluble.
⚡ Now Practise — 8 Questions
Tap an answer. Right or wrong, we explain why instantly. Learn from every tap!
Q1. Number of bones in an adult human:
Q2. Normal human body temperature is about:
Q3. Universal blood donor group is:
Q4. Functional unit of the kidney is:
Q5. Night blindness is caused by lack of Vitamin:
Q6. Largest internal organ of the body:
Q7. Haemoglobin carries which gas mainly?
Q8. Goitre is caused by deficiency of:
Lesson done? Your tick is saved on this device. Next chapter is waiting in General Science.
All Chapters →