Blood and its composition

• red coloured fluid connective tissue.
• Alkaline and salty in taste (pH 7.35-7.45).
• 7-8% of body weight.
• Average volume is 5-6 litres in male and 4-5 litres in female.
• Slightly denser than water (1.043-1.060 gm/ml).
• 5 times more viscous than water.
• Red due to presence of haemoglobin.
• Temperature – 100.4°F.
• Made up of plasma (55%) and blood corpuscles (45%).

Plasma

• Transparent clear yellowish liquid.
• Forms about 55% of the blood volume.
• Contains 90% water, 8% water,2% other dissolved substances like minerals, waste products, salts, carbohydrates, etc.
• Density is approx 1.025 gm/ml.

Blood corpuscles (blood cells)

• Forms about 45% of the blood volume.
• Three types are present.

Red blood cells

• Also called erythrocytes, haematids, erythriod cells.
• Shape: biconcave, disc shaped.
• Size: 7-8µm in diameter.
• Colour: red
• Nucleus: absent except in camel and ilama.
• Number: 5-5.5million/cu.ml in male and 4-4.5million/cu.ml in female.
• Produced in: red bone marrow of short bones and liver and spleen in in embryo.
• Destroyed in: liver and spleen ( extravascular) and inside blood vessels (intravascular).
• Life span: 120 days.
• Function: oxygen supply.
• Disorders: sickle anemia, hemolytic anemia, hereditary spherocytosis.

White blood cells

• Also called leukocytes.
• Shape: Amoeboid (irregular) shaped.
• Size: neutrophils 12-15µm, eosinophil 12-15µm, basophil 12-15µm, lymphocyte 7-10µm, monocyte 15-25µm
• Colour: colourless and transparent so appear to be white.
• Types: granulocytes and agranulocytes.
• Nucleus: lobed nucleus (unilobed or multilobed).
• Number: 4000-11000/cu.ml.
• Produced in: bone marrow, lymph nodes, spleen.
• Destroyed in: liver, spleen.
• Function: kill germs.
• Life span: 2-5 days.
• Disorders: leukaemia, leucopenia.

Platelets

• Also called thrombocytes.
• Shape: irregular.
• Size: 2-3 µm.
• Colour: colourless
• Nucleus: absent.
• Number: 150,000-450,000 microlitre.
• Produced in: bone marrow.
• Destroyed in: spleen and liver.
• Life span: 8-9 days.
• Function: form blood clot in the wound.
• Disorders: thrombocytosis, thrombocytopenia.

                                                                                          Image source:ck-12

References: 

i) https://www.hematology.org/education/patients/blood-basics#:~:text=Blood%20is%20a%20specialized%20body,to%20prevent%20excess%20blood%20loss

ii) https://www.medicalnewstoday.com/articles/196001

Blood and its composition