ABO Blood Grouping System
Functions of Blood System
Transport: to and from tissue cells
- Nutrients to tissue cells: amino acids, glucose, vitamins, minerals in solution in the plasma; lipids as lipoproteins.
- Oxygen: by red blood corpuscles.
- Wastes: urea, uric acid and some CO2 in solution in the plasma. Most CO2 is carried in the red blood corpuscles.
Temperature Regulation: by altering the blood flow through the skin.
Immunity: protection against pathogens — blood clotting; phagocytes, lymphocytes and antibodies distributed in blood.
Communication: hormones distributed to all parts of the body in the blood.
Composition of Blood
Plasma: pale yellow sticky liquid; 55% of blood volume.
Components: water 92%, dissolved protein 8%, glucose ABO Blood Grouping System, amino acids, vitamins, minerals, urea, uric acid, CO2, hormones, antibodies.
Textbook Diagram: structure of suspended solids of blood.
Red Blood Cells
- Tiny biconcave disc-shaped cells.
- Do not have a nucleus.
- Do not have mitochondria.
- Their cytoplasm is rich in haemoglobin.
- O2 binds to the iron in haemoglobin.
- Made in the bone marrow.
- Survive for about four months.
- Destroyed and recycled by the liver and spleen.
White Blood Cells (leucocytes)
- These are colourless cells and possess a nucleus.
- They function in defending the body against pathogens.
- Some ‘feed’ on pathogens by phagocytosis.
- Others produce antibodies, the specific ABO Blood Grouping System defence proteins.
- Made by the bone marrow and lymphatic tissue.
- These are tiny fragments of large bone marrow cells.
- They carry specialised blood clotting chemicals.
- The clotting chemicals are released where blood and lymph vessels are injured.
- A nucleus is not present in platelets.
Specialist White Blood Cells
Monocytes: largest white blood cells – engulf viruses, cancer cells, damaged and dead tissue cells.
T Lymphocytes (T cells) – made in the bone marrow, mature in the thymus.
- Helper T Cells: stimulate the multiplication of other lymphocytes.
- Killer T Cells: inject lethal chemicals into pathogenic cells.
- Suppressor T Cells: halt the immune response ABO Blood Grouping System when the infection has been overcome.
- Memory T Cells: give immediate future protection against the same pathogen.
B Lymphocytes (B cells): specific antibody producing cells.
ABO Blood Grouping System
Four groups. The blood group depends on the presence or absence of antigen A and antigen on the surface of red blood cells.
- Group A: antigen A only.
- Group B: antigen B only.
- Group AB: antigen A and antigen B are both present.
- Group O: antigen A is not present and antigen is not present.
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