The Human Body and Diseases
Overview
The Human Body and Diseases is a high-scoring topic in Railway NTPC and Group D exams. It covers body systems, vital organs, common diseases, their causes, symptoms, deficiency disorders, and vaccines. Questions frequently test knowledge of vitamins, blood groups, digestive and circulatory systems, pathogens, and immunity. Mastering this chapter with accurate facts, numbers, and names of scientists gives candidates a clear edge in the General Science section.
Typed Notes
Human Organ Systems and Key Facts
The human body has 11 major organ systems. The largest organ is Skin; the largest internal organ is Liver. The smallest bone is Stapes (in ear); the longest bone is Femur (thigh). The brain has three main parts: cerebrum (thinking), cerebellum (balance), medulla oblongata (involuntary actions). Kidneys filter blood and produce urine; the functional unit is Nephron. Normal RBC lifespan is 120 days; WBCs fight infection. Platelets help in clotting. The normal body temperature is 37°C (98.6°F). Exam tip: Remember 'Femur is the Longest, Stapes is the Smallest' bone.
Diseases — Causes, Pathogens and Vectors
Diseases are classified as bacterial, viral, fungal, protozoan, and deficiency-based. Tuberculosis (TB) — Mycobacterium tuberculosis (bacteria). Cholera — Vibrio cholerae. Typhoid — Salmonella typhi. COVID-19, Influenza, Rabies, Polio — caused by viruses. Malaria — Plasmodium vivax/falciparum (protozoan), vector: female Anopheles mosquito. Dengue and Chikungunya — Aedes aegypti mosquito. Filariasis (elephantiasis) — Wuchereria bancrofti (worm), vector: Culex mosquito. Ringworm — fungal infection. Exam tip: 'Anopheles = Malaria; Aedes = Dengue; Culex = Filaria' — memorise this vector trio.
Vitamins, Minerals and Deficiency Diseases
Vitamin A (Retinol) — Night blindness, Xerophthalmia. Vitamin B1 (Thiamine) — Beriberi. Vitamin B2 (Riboflavin) — Ariboflavinosis. Vitamin B3 (Niacin) — Pellagra. Vitamin B12 — Pernicious Anaemia. Vitamin C (Ascorbic acid) — Scurvy (bleeding gums). Vitamin D (Calciferol) — Rickets (children), Osteomalacia (adults). Vitamin E — Infertility. Vitamin K — Impaired blood clotting. Iodine deficiency — Goitre. Iron deficiency — Anaemia. Calcium deficiency — Osteoporosis. Exam tip: 'ADEK' are fat-soluble; all others are water-soluble. Vitamin C is destroyed by cooking (heat-sensitive).
Immunity, Vaccines and Blood
Immunity is of two types: Innate (natural, present from birth) and Acquired (developed after exposure or vaccination). Vaccines stimulate the immune system to produce antibodies. BCG vaccine — Tuberculosis. OPV/IPV — Polio (developed by Jonas Salk). DPT — Diphtheria, Pertussis, Tetanus. MMR — Measles, Mumps, Rubella. Blood groups (ABO system) discovered by Karl Landsteiner. Rh factor discovered by Landsteiner and Wiener. AB+ is the universal recipient; O− is the universal donor. Haemophilia is a genetic blood-clotting disorder linked to X chromosome. Normal haemoglobin: 12–16 g/dL in women, 13.5–17.5 g/dL in men.
Key Concepts
Revision ke liye ek nazar — exam se pehle yahi padhna hai.
- 01Blood has four groups — A, B, AB (universal recipient), O (universal donor) — discovered by Karl Landsteiner in 1901.
- 02Vitamins A, D, E, K are fat-soluble; B-complex and C are water-soluble — deficiency of Vitamin C causes Scurvy, Vitamin D causes Rickets.
- 03Insulin (produced by Beta cells of Islets of Langerhans in pancreas) regulates blood sugar; its deficiency causes Diabetes Mellitus.
- 04Malaria is caused by Plasmodium parasite, transmitted by female Anopheles mosquito; Dengue by Aedes aegypti mosquito.
- 05The human heart has 4 chambers — 2 atria and 2 ventricles; normal heartbeat is 72 beats per minute and BP is 120/80 mmHg.
Questions & Solutions
Pehle khud try karo — phir solution kholo. Yahi tariqa topper banata hai.
Which gland is called the 'master gland' of the human body and why?
Name the disease caused by deficiency of Vitamin B1 and describe its main symptoms.
What is the role of the Nephron in the human body?
Differentiate between bacteria and viruses as disease-causing agents with one example each.
What is the significance of the Rh factor in blood transfusion and pregnancy?
Railway exams repeatedly test: blood groups (O universal donor, AB universal recipient), vitamin deficiency diseases (Scurvy=C, Rickets=D, Beriberi=B1), disease-causing pathogens and their vectors (Anopheles=Malaria, Aedes=Dengue, Culex=Filaria), key organ facts (largest=Liver, longest bone=Femur, smallest bone=Stapes), normal body values (BP 120/80, pulse 72/min, temperature 37°C), and vaccines. Accuracy on numbers and names is critical.
Chapter-end quiz
4 MCQsOption tap karo — turant pata chalega sahi ya galat, explanation ke saath.
Q1.Which mosquito is responsible for transmitting Dengue fever?
Q2.Which vitamin is synthesised by the human body on exposure to sunlight?
Q3.The universal blood donor group is:
Q4.Which organ produces bile juice that helps in digestion of fats?
Mark karo — dashboard par progress dikhega.