Sci-pt1

• Circulatory system


  One of the most important systems of the human body
• Circulatory system


  1. Transports nutrients and oxygen to body cells

  2. Collects waste products for removal

  3. Regulates body temperature

  4. Carries substances that protect the body from diseases
• Functions of blood circulatory system


  • Transportation
  • Protection
  • Regulation
• Transportation


  Transports nutrients and oxygen to all cells and waste products from cells to the excretory organ
• Protection


  WBC produces antibodies which increase the immunity power to fight against pathogens, virus and bacteria
• Regulation


  Regulates the amount of water and temperature
• Parts of the blood circulatory system

  • Blood
  • Blood vessels
  • Heart
• Blood


  A fluid connective tissue flowing in its closed path called blood vessels
• Blood is red in color due to presence of iron rich pigment called hemoglobin in RBC
• Blood


  Consists of 55% plasma and 45% blood cells
• Average human body consists of 5.5 litres of blood
• Blood circulation


  Circulates in the artery and vein to supply nutrients and oxygen to different tissues of the body and carry back wastes
• Blood


  Composed of 55% blood plasma and 45% blood cells
• Blood Plasma

  • Transparent yellowish liquid
  • Contains about 90% water, 2% different types of proteins and 2% clotting factors
  • Blood cells are suspended in the plasma
• Functions of Blood Plasma

  1. Transports digested food to different parts of the body

  2. Transports various waste materials to the excretory organs

  3. Maintains the amount of water in the body, regulates the body temperature, helps in blood clotting
• Blood Cells/Blood corpuscles


  • RBC, WBC, and platelets
  • Occupy 45% of total volume of blood
• Red Blood Cells (RBC)

  • Also called erythrocytes
  • Circular, biconcave and disc shaped cells, have no nuclei
  • One cubic mm of blood contains about 4.5 million to 6 million RBCs
  • Formed in the bone marrow and destroyed in the liver or spleen
  • Life span is about 120 days
  • Contain haemoglobin which is an iron pigmented substance due to which blood is red in colour
  • Function is to transport oxygen and carbon dioxide between lungs and all parts of the body
• Deficiency of RBC in the blood

  Leads to the disease called anaemia
• Excess amount of RBC in the blood


  Causes polycythemia
• White Blood Cells (WBC)

  • Also called leukocytes
  • Irregular in shape, contain nucleus but lack haemoglobin
  • One cubic mm of blood contains about 4000 to 11000 WBCs
  • Formed in the bone marrow, lymph nodes and destroyed in the spleen/ liver
  • Life span is about 12 to 14 days
  • Cells of the immune system involved in defending the body against pathogens and foreign materials
  • Produce antibodies
• Excess amount of WBCs in blood

  Leads to the disease called Leukaemia (blood cancer)
• Less WBCs in blood

  Leads to leukopenia (baldness) caused due to fall in neutrophil cells
• Types of Leucocytes


  • Granulocytes (neutrophiles, eosinophils and basophils)
  • Agranulocytes (monocytes and lymphocytes)
• Platelets


  • Also called thrombocytes
  • Smallest blood cells, oval in shape and no nucleus
  • Formed in the bone marrow and destroyed in the spleen
  • One cubic mm of blood contains about 1.5 lakhs to 4.5 lakhs platelets
  • Life span 5 to 10 days
  • Contain a pigment called fibrinogen which helps in blood clotting and prevent the excess loss of blood
• Less platelets


  Causes thrombopenia - excessive bleeding can occur (Haemophilia)
• Excess platelets


  Causes thrombocytosis - obstruct blood vessels
• Functions of Blood


  • Transport oxygen from lungs and all parts of the body
  • Carry waste products from different tissues to the excretory organs
  • Carry hormones produced by endocrine glands to the target cells
  • Destroy various microorganisms and pathogens
  • Regulate body temperature
  • Help in blood clotting and minimize the excess loss of blood