Facts of Human Body for SSC and RRB Exam

This post contains facts of Human Body for SSC and for other competitive exams like SSC CGL,SSC CHSL, SSC MTS, RRB UPSC, CDS, NDA, state-level exams.

Facts of Human Body

    • Length of alimentary canal – 8 metres approx
    • BMR – 1600 K. Cal/day
    • Number of cells in the body – 75 trillion
    • Longest bone – Femur (Thigh Bone)
    • Smallest bone – Ear ossicle, Stapes
    • Weight of brain – 1400 gms
    • Blood volume – 6.8 litres (in 70 kg body)
    • Normal B.P – 120/80 mm Hg
    • Number of R.B.C – a) In male : – 4.5-5.0 million/ cubic mm
      b)In female: -4.0-4.5 million/ cubic mm
    • Life Span of R.B.C – 120 days
    • Normal W.B.C count – 5000 – 10000/ cubic mm
    • Life span of W.B.C – 3 to 4 days
    • D.L.C (Differential leucocyte count) – a)Basophils – 0.5 – 1%
      b)Eosinophild – 1-3%
      c) Monocytes – 3-8%
      d) Neutrophils- 40-70%
      e)Lymphocytes – 2-25%
  • Blood platelets count – 2,00,000-4,00,000/cubic mm
  • Haemoglobin- a)In male – 14 – 15.6gm/100 c.c. of blood
    b)In Female – 11-14 gm/100 c.c. of blood
  • Hb content in body – 500 – 700 gm
  • Universal blood donor – O Rh –ve
  • Universal blood recipient – AB
  • Blood clotting time – 2-5 minutes
  • Average body weight – 70 Kg
  • Normal body Temperature –98.4⁰ F or 37⁰C
  • Breathing rate – 16 -20/minute
  • Dental formula – adult : 2123/2123 = 32; child : 2120/2120 = 22 milk teeth
  • Number of cranial nerves – 12 pairs
  • Number of Spinal nerves – 31 pairs
  • Largest Endocrine gland –  Thyroid
  • Gestation Period – 9 months (253-266 days)
  • Normal Heartbeat – 72-75/minute
  • Largest gland – Liver
  • The largest muscle in the body – Gluteus maximus (Buttock muscle)
  • Largest smooth muscle – Uterus of a pregnant woman
  • The smallest muscle in the body – Stapedius
  • Largest artery – Abdominal aorta
  • Largest vein – Inferior venacava
  • Largest W.B.C – Monocyte
  • Smallest W.B.C – Lymphoyte
  • Greatest regeneration power – In liver
  • Longest nerve – Sciatic
  • Longest cell – Neuron (nerve cell)
  • Menstrual cycle – 28 days
  • Menopause – 45-50 days
  • Minimum regeneration power – in brain cells
  • Minimum distance for proper vision – 25 cm
  • Type of Placenta – Haemochorial (Chorioallantoic)
  • Pulse rate – 72/minute
  • The volume of semen – 2-4 ml/ejaculation
  • Normal sperm count – 200 -350 million/ejaculation
  • ESR(normal Erythrocyte sedimentation rate) – 4.10 min/hour
  • Thinnest skin – Conjunctiva
  • pH of gastric Juice – 1.4
  • pH of Urine – 6.0
  • pH of Blood – 7.35-7.45

Check here –General Science Quiz Set 6

Balanced Diet

Components are – Carbohydrates, Fats, Proteins, Minerals, Vitamins, Water and Roughage

What is Balanced Diet?

If all the above-mentioned components are present in perfect proportions and quantity for maintaining the body in a perfect and healthy state, then the food is called Balanced diet.


The main 3 elements are Carbon, Hydrogen and Oxygen

Requirement on Daily Basis – 500 gms; 1 gm gives 17KJ of energy

Sources of carbohydrates: -3 main kinds of cereal (wheat, rice, maize), sugarcane, milk, fruits, honey, beet

The carbohydrates in food eaten are processed in the alimentary canal and liver are then are supplied to the tissues mainly as glucose; known as blood sugar

Cellulose, starch and sugar are 3 types

Structurally, carbohydrates are of three types : -Monosaccharides, Disaccharides and Polysaccharides

Excess of carbohydrate is stored in the liver in the form of Glycogen

Fats :-

Daily requirement – 50gms

Provides twice the energy of carbohydrates

Act as the reserve food material because excess fat is stored in the liver and as adipose tissue

An enzyme called Lipase digests fats. It breaks down into fatty acids and glycerol

Proteins –

Made up of Carbon, Hydrogen, Oxygen and Nitrogen

For growth and repairmen, it is important

Made up of amino acids

Kwashiorkor and Marasmus are the diseases that occur due to the deficiency of Protein

Vitamins –

Vitamins are necessary for growth, good vision and health, proper digestion of the body. They do not provide any energy to our body.

Vitamins can be divided into two categories: –

Water-soluble Vitamins:- Vitamin B-complex, Vitamin C

Fat Soluble – Vitamin A, Vitamin D, Vitamin E, Vitamin K

Water : – Important in digestion, transportation, excretion and to regulate body temperature

Roughage :-

Fibrous material present in the cell wall of plants.

Mainly contains cellulose.

It does not provide energy but only helps in retaining water in the body.

One of the common sources is Daliya.

Check here –General Science Quiz Set 8

Types of Vitamins

VitaminChemical NamePropertiesDeficiency Disease
ARetinolGeneral Health giving vitamin, can be stored in liverNight Blindness
B1ThiamineFor growth, carbohydrates metabolism, the functioning of healthBeri –Beri
B2RiboflavinFor keeping skin and mouth healthyCheilosis
B5NiacinFor healthy skin, sound mental healthPellagra
B6PyridoxineProcessing of proteins and for the nervous systemConvulsions in Child
B12CynacobalaminRequired for formation and maturation of RBCsPernicious anaemia
CAscorbic AcidFor keeping teeth, gums and joints healthy. Gets destroyed on heatingScurvy
DCalciferolFor normal bones and teeth, can be stored in the liverRickets
ETocopherolFor normal reproduction, removes scars and wrinklesSterility
KPhylloquinoneFor Formal clotting of bloodHaemophilia


Blood is a fluid connective tissue. Its quantity is 6.8 litres in man and 500 ml less in a woman. It constitutes 6-8% of body weight and has a pH of 7.4

Three types of Blood Cells: –

1)Red Blood Cells(RBC)

2)White  Blood cells (WBC)


Red Blood Corpuscles (RBC): – They are also called erythrocytes, disc-shaped, no nucleus. It contains a pigment which is called Haemoglobin, which gives blood its red colour and transports oxygen and carbon dioxide.

Red blood cells are manufactured in Bone marrow

The Life of Red Blood Cells is 120 days. Number of RBCs is 4.5 – 5 million/ cubic mm of blood

White Blood Corpuscles  (WBC) : – Also called leucocytes, they are rounded with a nucleus and far less numerous than RBCs(8,000 per cubic mm of blood)

Manufactured in Red Bone marrow

Act as the soldiers of Body’s defence system

Platelets: –

Also called thrombocytes and are about 2,50,000 per cubic mm of blood

Manufactured in red Bone marrow.

It helps the blood to clot.

Blood Groupings

Father of Blood Grouping: Karl Landsteiner

He discovered A, B and O blood groups

Decastello and Sturle discovered AB blood groups.

Blood Group               Can donate to                     Can receive from

A                                       A,AB                                        A,O

B                                       B,AB                                        B,O

AB                                      AB                                        A,B,AB,O

O                                    A, B, AB, O                                   O

RH factor

It is a blood antigen found in RBC.

A person can be Rh+ or Rh- depending upon the presence of Rh factor in RBC

Rh+ can receive blood from both Rh+ and Rh- but Rh- can receive blood only from Rh- only

Blood transfusion techniques were developed by James Blundell.