Blood And Blood Groups

Question 1

Describe the constituents of blood

Answer 1

Blood is a connective tissue. It circulates constantly around the body. It transports:
Dissolved gasses including oxygen
Nutrients
Hormones
Heat
Antibodies and cells of the immune system
Plasma proteins, including clotting factors
Drugs
Wastes

Question 2

Outline the production of erythrocytes, leukocytes, platelets (thrombocytes) and plasma

Answer 2

Erythrocytes (red blood cells)- produced in red bone marrow- function transport respiratory gases
Leukocytes (white blood cells)- developed from stem cells, known as erythropoietin- function make up immune system/response
Platelets- produced in bone marrow- function prevent and stop bleeding
Plasma- most synthesised in liver, except antibodies produced by B cells functions- maintaining osmotic pressure of blood, transport nutrients/hormones/waste products, gases ect.

Question 3

Identify the factors important in erythropoiesis (production red blood cells)

Answer 3

Immature cells released into blood stream as reticulocytes and mature into erythrocytes after a few days
Vitamin B12 and folic acid are required
No nucleus so cannot divide, numbers maintained by balancing production of red bone marrow and breakdown (mainly in liver and spleen)

Question 4

Describe the 4 main blood groups

Answer 4

A has antigen A presenting cells on its surface. So it cannot make anti-A antibodies but can make anti-B antibodies.
B has antigen B presenting cells on its surface. So it cannot make anti-B antibodies but can make anti-A antibodies
AB has both A and B presenting cells on its surface, so can make neither antibodies (universal recipients)
O has no presenting antibodies, so can make both anti-A and anti-B antibodies (universal donor)

Question 5

Outline the importance of the Rhesus factor in blood grouping

Answer 5

About 85% of people have this antigen (Rhesus antigen), they are Rhesus +ive and do not make Rhesus antibodies.
Those that don’t have the antigen, produce the antibodies if they are exposed to the antigen eg. Through pregnancy.
Not normally much of an issue in first pregnancy but is in second.
Can cause anaemia, but can be correct through blood transfusions.

Question 6

Outline the concept of compatibility/incompatibility between donor and recipient

Answer 6

A: can donate to A and AB, can receive A and O
B: can donate to B and AB, can receive B and O
AB: can donate to AB only, can receive ALL
O: can donate to ALL, can receive O only