The Human Body and Nutrition
Overview
The Human Body and Nutrition is a high-yield topic for SSC CGL and CHSL exams. It covers the structure and functions of body systems, essential nutrients, vitamins, minerals, deficiency diseases, and digestive processes. Questions frequently test vitamin sources, deficiency diseases, enzyme functions, and caloric values of nutrients. A solid grasp of these facts can secure 3-5 marks in the General Awareness section with minimal preparation time.
Typed Notes
Essential Nutrients and Caloric Values
The human body requires six classes of nutrients: carbohydrates, proteins, fats, vitamins, minerals, and water. Carbohydrates are the primary energy source, yielding 4 kcal per gram. Proteins also yield 4 kcal per gram and are essential for growth and repair — they are called 'building blocks of life.' Fats yield the highest energy at 9 kcal per gram and help absorb fat-soluble vitamins A, D, E, and K. Roughage (dietary fibre) aids digestion but provides no calories. Water constitutes about 70% of body weight and is vital for all metabolic reactions.
Vitamins — Types, Sources, and Deficiency Diseases
Vitamins are classified as fat-soluble (A, D, E, K) and water-soluble (B-complex, C). Vitamin A (Retinol) — deficiency causes Night Blindness and Xerophthalmia; source: carrots, liver. Vitamin B1 (Thiamine) — deficiency causes Beriberi. Vitamin B2 (Riboflavin) — deficiency causes Ariboflavinosis. Vitamin B12 (Cobalamin) — deficiency causes Pernicious Anaemia. Vitamin C (Ascorbic acid) — deficiency causes Scurvy; source: citrus fruits. Vitamin D (Calciferol) — deficiency causes Rickets (children) and Osteomalacia (adults); synthesised by skin in sunlight. Vitamin K — essential for blood clotting; deficiency causes excessive bleeding.
Human Digestive System and Key Enzymes
Digestion begins in the mouth where Salivary Amylase (Ptyalin) breaks down starch into maltose. The stomach secretes Pepsin (breaks proteins) and Hydrochloric Acid. The small intestine is the main site of digestion and absorption. The Pancreas secretes Pancreatic juice containing Amylase, Lipase (digests fats), and Trypsin (digests proteins). The Liver produces Bile, stored in the Gall Bladder, which emulsifies fats. The large intestine absorbs water. The total length of the small intestine is approximately 6-7 metres. Villi in the small intestine increase surface area for absorption.
Important Body Facts and Mineral Deficiencies
The human body has 206 bones in adults and 300 bones at birth. The normal blood pH is 7.35-7.45 (slightly alkaline). Normal RBC lifespan is 120 days; WBC lifespan is 2-4 days. Blood group O is the universal donor; AB is the universal recipient. Iron is needed for haemoglobin formation — deficiency causes Anaemia. Iodine deficiency causes Goitre (enlarged thyroid). Calcium deficiency causes Tetany and weak bones. Fluoride deficiency causes dental caries; excess fluoride causes Fluorosis. Zinc deficiency causes loss of taste and smell. The human heart beats approximately 72 times per minute.
Key Concepts
Revision ke liye ek nazar — exam se pehle yahi padhna hai.
- 01Carbohydrates and fats provide 4 kcal/g and 9 kcal/g respectively; proteins provide 4 kcal/g — fats give more than double the energy of carbs or proteins.
- 02Vitamin C (Ascorbic acid) deficiency causes Scurvy; Vitamin D deficiency causes Rickets in children and Osteomalacia in adults — both are very frequently asked in SSC papers.
- 03The largest gland in the human body is the Liver; the largest organ is the Skin; the smallest bone is Stapes (in the ear).
- 04Insulin is secreted by Beta cells of Islets of Langerhans in the Pancreas and regulates blood glucose levels — deficiency leads to Diabetes Mellitus.
- 05Iron deficiency causes Anaemia; Iodine deficiency causes Goitre; Calcium deficiency causes Tetany — mineral-deficiency disease pairs are direct SSC exam questions.
Questions & Solutions
Pehle khud try karo — phir solution kholo. Yahi tariqa topper banata hai.
Which vitamin is synthesised by the human skin when exposed to sunlight, and what disease does its deficiency cause in children?
Name the enzyme present in saliva and state its function in digestion.
What is the caloric value of fats per gram, and why are fats considered a concentrated source of energy?
Which organ secretes insulin, which cells produce it, and what condition results from insulin deficiency?
List any four mineral deficiency diseases with the corresponding mineral that is deficient.
For SSC exams, focus on vitamin-deficiency disease pairs, caloric values (fat=9 kcal, carbs=protein=4 kcal), key enzymes and their functions, mineral deficiency diseases, and important body facts like bone count (206), blood pH (7.35-7.45), and universal blood donor (O). These facts appear repeatedly across CGL and CHSL papers and can be memorised using simple association tricks.
Chapter-end quiz
4 MCQsOption tap karo — turant pata chalega sahi ya galat, explanation ke saath.
Q1.Which of the following vitamins is essential for blood clotting?
Q2.The universal blood donor belongs to which blood group?
Q3.Which is the largest gland in the human body?
Q4.Deficiency of Vitamin B1 (Thiamine) causes which disease?
Mark karo — dashboard par progress dikhega.