12th Zoology

Blood – Composition of plasma – Blood cells


The blood is a fluid connective tissue. It consists of liquid plasma and
cells. The plasma makes up 55% of the total volume and 45% of cells or
formed elements. The total blood volume in human female is about 4-5 litres
and 5-6 litres in males.


The blood plasma is a slightly alkaline fluid. It is straw coloured.

Composition of plasma

Components Functions

1. Water – as a slovent and suspending medium
for blood components.

2. Plasma proteins- Albumin – Osmotic pressure.
Globulins – Antibody formation
Fibrinogen – Blood clotting.

3. Ions – Na, K, Ca, Mg, Cl
, – Osmosis, acid-base balance.
Fe, PO

, H and HCO
– buffer etc.,

4. Nutrients – Glucose, amino – source of energy, building blocks
acids, triglycerides, cholesterol, – enzyme activity.

5. Waste products – Urea, uric – excreted by the kidneys.
acid creatinine, ammonia
Bilirubin – breakdown product of erythrocytes
Lactic acid – product of anaerobic respiration.

6. Gases
Oxygen – for aerobic respiration
– waste product of respiration
Nitrogen – inert gas.

7. Regulating substances
Hormones and Enzymes – body functions
Blood cells or formed elements
There are three types of blood cells or corpuscles. They are

1. Red Blood Corpuscles (RBC) or Erythrocytes

These are circular, biconcave and non-nucleated cells. Males have
about 5.2 million erythrocytes per cubic millimeter of blood (range : 4.2-5.8
million). Females have about 4.5 million/mm3 (range 3.6-5.2 million). Each disc shaped RBC is about 7.5 mm in diameter. Their main
component is a pigmented protein, haemoglobin. It gives red colour to the
blood. The haemoglobin transports O2. The oxygenated form of
haemoglobin is called oxyhaemoglobin.
Erythrocytes stay in circulation for about 120 days in males and 110
days in females. They are manufactured in the marrow of bones such as ribs
and vertebrae. They disintegrate in the spleen and liver.

2. White Blood Corpuscles (WBC) or Leucocytes

These are clear cells lacking haemoglobin. They are nucleated cells
exhibiting amoeboid movement. They protect the body against invading
micro-organisms and remove dead cells from the body. There are five types
of leucocytes.
a). Neutrophils – These are the most common type of leucocytes (60-70%)
in the blood. Their nuclei can occur in more than one form. Hence they are
called polymorphonuclear neutrophils (PMN).
b). Eosinophils (0.5-3.0%) – They are motile cells that leave the circulation
to enter the tissues during an inflammatory reaction. During allergy reaction
their number increases.
c). Basophils (0.1%) – They play a role in allergic and inflammatory
reaction. They contain heparin which inhibits blood clotting.
d). Lymphocytes (20-30%) – These are smallest leucocytes. They are more
common in lymphatic tissues namely the lymph nodes, spleen, tonsils and
thymus. Lymphocytes, called B-cells can produce proteins called
antibodies that can get attached to the bacteria and destroy them. T-cells protect us against viruses by attacking and destroying cells in which viruses
are reproducing.
e). Monocytes (1-4%) – These are largest leucocytes. They destroy
bacteria, dead cells and cell fragments. During chronic infection their number

3. Blood Platelets or Thrombocytes

These are minute fragments of cells that play a very important role in
coagulation of blood. Their life expectancy is 5-9 days.

Related Topics in Zoology:

Bio Zoology All Important Topics

  1. Human Physiology Introduction

  2. Nutrition

  3. Carbohydrates Poly hydroxyaldehydes (or) ketones

  4. Proteins (Polypeptides)

  5. Lipids

  6. Vitamins – Functions Of Vitamins

  7. Deficiency of Vitamin

  8. Minerals – Water – Role of water

  9. Balanced diet

  10. Obesity

  11. Digestive System

  12. Dental Caries (Tooth decay)

  13. Root Canal Treatment

  14. Peptic ulcer

  15. Hernia and Types

  16. Appendicitis (Appendix)

  17. Gall Stones

  18. Hepatitis

  19. Fractures – Types of fractures

  20. Mechanism of fracture

  21. Dislocation of joints

  22. Arthiritis

  23. Rickets and Osteomalacia – Orthopedics

  24. Muscles

  25. Mechanism of muscle contraction

  26. Types of muscle contraction

  27. Myasthenia Gravis

  28. Respiration – Process of pulmonary respiration

  29. Mechanism of Breathing

  30. Regulation of Respiration

  31. Pneumonia Tuberculosis Symptoms Treatment

  32. Bronchitis – Acute bronchitis, Chronic Bronchitis Causes

  33. Circulatory System – Functioning of Human heart

  34. Cardiac Cycle

  35. Coronary blood vessel and its significance

  36. Myocardial infarction

  37. Angina pectoris

  38. Angiogram – Angioplasty

  39. Atherosclerosis

  40. Heart block Echo cardiography Heart Valves

  41. Rheumatic Heart Disease (RHD), ICCU – (Intensive Coronary Care Unit)

  42. Blood Pressure

  43. Heart transplantation

  44. Pulse rate

  45. Cardio Pulmonary Resuscitation (CPR)

  46. Blood – Composition of plasma – Blood cells

  47. Clotting of Blood or Haemostasis

  48. Thrombosis

  49. Nervous system Co-ordination systems

  50. The Brain – Fore Brain, Midbrain, Hindbrain

  51. Memory

  52. Sleep – Types of sleep

  53. Stroke – Brain haemorrhage

  54. Alzheimer – Meningitis (Brain fever)

  55. Conditioned reflex

  56. Electroencephalography EEG

  57. Right and Left brain concept

  58. Spinal cord functioning

  59. Chemical co-ordination – Functions of Endocrine glands

  60. Hypothalamus

  61. Pituitary gland – hormone

  62. Hormones of Neurohypophysis – vasopressin

  63. Thyroid gland

  64. Parathyroid Gland

  65. Pancreas

  66. Adrenal gland

  67. Gonads

  68. Receptor Organs – Eye

  69. Photochemistry of Retinal visual Pigments

  70. Errors of refraction

  71. Optometry – Retinopathy

  72. Cataract – Lens Replacement – Glaucoma – Nyctalopia

  73. Eye Infections and Eye Care

  74. Ear

  75. Mechanism of hearing

  76. Defects of the ear

  77. Hearing Aid – Noise pollution

  78. Skin and functions of skin

  79. Melanin functions

  80. Effects of solar radiation / UV radiation – Skin grafting

  81. Dermatitis

  82. Tongue – Mechanism of Stimulation

  83. Excretion Ureotelism Nephron

  84. Mechanism of urine formation

  85. Renal Failure, Dialysis, Kidney Machines

  86. Kidney stone – Kidney transplantation

  87. Diabetes mellitus

  88. Functioning of male reproductive system

  89. Functioning of female reproductive system

  90. Ovulation and fate of the ovum – Menstrual cycle

  91. Fertilization

  92. Birth control

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