Notes

Blood:
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- The system through which blood transports to different parts and organs of the body is known as "Blood Circulatory System"
- Blood distributes adequate oxygen and nutrients
- Two types of circulatory system:
(1) Blood Circulatory System (2) Lymphatic Circulatory System
- Blood is a red colored viscous, slightly alkaline and salty fluid.
- Due to the presence of hemoglobin, blood appears red.
- Blood originates from bone marrow.
- Blood has two components:
(1) Plasma (2) Blood Cells

Blood Group:
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- Blood can be classified into different groups based on the number of antibodies and antigens. This is known as Blood Group
- In 1701, scientist Karl Landsteiner divided blood into 4 groups:
(1) A (2) B (3) AB (4) O

- A possesses antigen A and antibody b
- B possesses antigen B and antibody a
- AB possesses antigen A,B and neither antibody
- O possesses neither antigen and antibody a,b
- A can donate to A, AB and receive from A, O.
- B can donate to B, AB and receive from B, O.
- AB can donate to AB and receive from A, B, AB, O (universal recipient)
- O can donate to A, B, AB, O and only receive from O (universal donor)
- A healthy person can donate 450 milliliter of blood.

Plasma:
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- The colorless fluid part of blood which constitutes about 55% volume of whole blood is "Plasma"
- Main component of plasma is water.

Blood Corpuscles:
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- Blood is made out of 3 types of cells:
(1) Red Blood Cells (2) White Blood Cells (3) Platelets

Red Blood Cells:
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- Another name is erythrocytes
- Largest in number among the 3 blood cells
- Plays an important role in transportation of oxygen through blood
- Red Blood Cell is produced in bone marrow.
- Viability is 120 days
- Has no nucleus
- There are 5 million red blood cells per cubic milliliter of an adult male
- It is 500 times more than that of White Blood Cells
- Red Blood Cells are more in males than females
- Number of Red Blood Cells in infants are comparatively high.
- Every second, large number of red blood cells are destroyed and equal number are being produced.

White Blood Cells:
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- Another name is leucocytes.
- There are 5-10 thousand white blood cells per cubic milliliter of an adult male
- Viability is 20 days
- Produced in bone marrow and lymphatic glands
- Irregular in shape
- White Blood Cells engulfs germs by spreading pseudopodia. This process is known as phagocytes.
- The dead White Blood Cells turn into pus.
- Excessive White Blood Cells can cause leukemia.
- White Blood Cells produce Antibody.

Platelets:
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- Another name is thrombocytes.
- They remain in cluster
- There are 2.5 million platelets per cubic milliliter
- They originate from bone marrow
- Platelets help in Blood clotting or coagulation
- Whenever a blood vessel is damaged, immediately a chemical substance known as thromboplastin is released by the platelets
- If adequate number of platelets does not exist, blood clotting may not occur.

Functions of Blood:
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- Balancing the temperature condition
- Hormone transport
- Blood clotting
- Removal of waste products
- Removal of Carbon Dioxide
- Transport of digested food
- Transport of Oxygen
- Prevention of diseases

Blood Vessels:
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- The system through which mass flow of blood occurs is known as blood vessels.
- There are 3 types of blood vessels:
(1) Artery (2) Capillary (3) Vein

Artery:
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- The blood vessels which carry oxygenated blood away from the heart to different organs are arteries
- All arteries except pulmonary artery carry oxygenated blood
- Made of 3 layers: (1) Turnica Externa (2) Turnica Media (3) Turnica Interna
- Walls are elastic and thick
- No valves
- Narrow walls and passage

Vein:
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- The blood vessels which carry disoxygenated blood from different organs towards the heart are veins
- All veins except lung vein carry disoxygenated blood
- Made of 3 layers
- Has valves
- Wide walls and passage
- Walls are less elastic and thin

Capillary:
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- The hair like small delicate blood vessels which are visible in the muscle fibre are known as capillary.
- Capillary connect with the smallest artery on one side and veins on the other
- Capillary has thin walls