Human Blood – Complete Details

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Human Blood

Blood is a fluid connective tissue that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells. Human Blood is divided into two parts – Plasma and Blood Corpuscles.


60% of human blood is Plasma and rest 40% part is Blood Corpuscles.

Constitution of Normal Blood

Hematocrit 45 ± 7 (38–52%) for males
42 ± 5 (37–47%) for females
pH 7.35–7.45
base excess −3 to +3
PO2 10–13 kPa (80–100 mm Hg)
PCO2 4.8–5.8 kPa (35–45 mm Hg)
HCO3− 21–27 mM
Oxygen saturation Oxygenated: 98–99%
Deoxygenated: 75%


Blood Plasma
Blood plasma is a yellowish liquid component of blood that holds the blood cells in whole blood in suspension. It is the liquid part of the blood that carries cells and proteins throughout the body.

Constituent Osmolality (mosm/kg)
Sodium 135–145
Potassium 3.6–5.1
Chloride 95–105
Calcium 1.5
Magnesium 1
Urea 5
Glucose 5
Protein 1

Blood Corpuscles
It is divided into three parts
1. Red Blood Corpuscles
2. White Blood Corpuscles
3. Blood Platelets

Important Facts :
  • RBC is formed in Bone Marrow.
  • There is no nucleus in RBC.
  • Life Span of RBC is 20 to 120 days.
  • RBC contains Haemoglobin.
  • Anemia disease is caused due the deficiency of haemoglobin.
  • At the time of sleeping RBC reduced by 5% and the people who are at the height of 4200 meters RBC increases by 30% in them.
  • Formation of WBC takes place in Bone Marrow,lymph node and sometimes in liver and spleen.
  • Nucleus is present in the WBC.
  • Life span of WBC is 2 to 4 days.
  • Main function of WBC is to protect the body from the disease.
  • The ratio of RBC & WBC is 600:1.
  • WBC is also called Leucocytes.
  • Blood Platelets is found only in the blood of human and other mammals.
  • Blood Platelets is also formed in Bone :Marrow.
  • There is no nucleus in Blood Platelets.
  • Life span of Blood Platelets is from 3 to 5 days.
  • Main function of Blood Platelets is to help in clotting of blood.
  • Blood Platelets dies in the spleen.
  • Blood Platelets is also called Thrombocytes.

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