Blood groups- Human Bio

What are blood groups and why do they exist?

• surface of red blood cells coated with sugar and protein molecules that are able to stimulate immune system

• Molecules called antigens

• Protein produced by immune system is called an antibody

• antigen and antibody combine to form complex, and cause reaction

• ABO and Rh groupings important for blood transfusions

What are antigens, and how do they work?

• any cell or substance that has potential to cause the white blood cells to attack, is an antigen

• White blood cells circulate around body and ‘read’ outer surface of cells to determine if the molecules on the surface are “self” or “non-self”

• When it comes across a ‘non-self’ cell/substance, it attacks

What are antibodies, and how do they work?

• Lymphocytes responding to a ‘not self’ by producing a special protein called antibody

• When lymphocytes read the surface of a cell and realises it is ‘not-self’, it responds with antibodies

• Antibodies are able to bind to antigens, in a lock and key type model

What is agglutination?

• lots of antibodies lock onto their corresponding antigens in the blood

• That brings many antigens together into one location, “clumping” lots of antigens (bad) together

What are ABO Blood groups?

• 2 sugar antigens involved; antigen A + antigen B

• Can have only A, only B, both or neither antigens

A (antigen A)

B (antigen B)

AB (both antigens)

O (neither)

How do the antibodies and antigens react?

Body’s ability to make antigens and person’s ABO determined by DNA (Inherited)

Antibody reacts AGAINST Antigen;

Anti-A against Antigen A

Anti-B against Antigen B

A person’s immune system is able to recognise their own antigens and will not produce antibodies for them, but willl produce either antibody, group O produce both

What does it mean to have Blood type A?

Have the ‘A’ sugar marker embedded in your red blood cells

Red blood cells have ‘antigen A’ marker

Plasma has anti-b antibodies, block any B antigens

Receive- A or O

Block- B

What does it mean to have Blood type B?

Have the ‘B’ sugar marker embedded in your blood cells

Red blood cells have ‘antigen B’ marker

Plasma has Anti-A antibodies , attack A antigens

Receive: B + O

Attack: A

What does it mean to have Blood type AB?

have both A and B sugar marker embedded in your blood cells

Has both antigen A and Antigen B markers

Receive: All

What does it mean to have Blood type O?

red blood cells lack both A sugar marker and B sugar

Red blood cells do not have either antigen A or B marker

Have BOTH anti-A and anti-B antibodies, attack any A or B Antigens

Receive: Only O

What is Rhesus Blood groups?

system also based on antigen that occurs on surface of the red blood cells

Rh antigens are proteins

Rh antigens = Rh+

No Rh antigens = anti-Rh

What does having Rh+ blood mean?

means you HAVE Rh (d antigen) on the surface of your red blood cells

Will NOT be anti D antibodies in the blood

What does having Rh- blood mean?

• means you DO NOT have Rh (d antigen) on the surface of your red blood cells

• There WILL be anti D antibodies in the blood