Blood And Blood Components LO

Question 1

Describe constituents of blood

Answer 1

Red blood cells - 45% - carry oxygen
White blood cells - <1% - fight infection
Platelets - <1% - help blood clot
Plasma - 55% - contains salt and proteins

Question 2

Outline production of erythrocytes

Answer 2

1) starts in bone marrow as a pluripotent stem cell
2) differentiates into erythroblast
3) synthesis of haemoglobin and nucleus is expelled = reticulocyte
4) reticulocyte matures over 1-2 days and leaves bone marrow

Question 3

Function and structure of erythrocytes

Answer 3

Biconcave discs, flexible membrane so can squeeze through capillaries
Carry haemoglobin - a protein which O2 binds
Carry some CO2
Membrane made of glycolipids which are antigens responsible for blood types
Live for 120 days

Question 4

Outline formation of leucocytes

Answer 4

Develop from myeloid stem cells or lymphoid stem cells

Question 5

Function and structure of leucocytes

Answer 5

Have a nucleus
Have major histocompatibility antigens for immunological purposes
Granular - filled with granules
Agranular - monocytes develop into macrophages in tissues
Can live for months/years
Can leave blood stream to fight pathogens

Question 6

Outline formation of thrombocytes (platelets)

Answer 6

Formed from fragments of megakaryocytes under the influence of thrombopoietin
In red bone marrow, then enter circulation

Question 7

Describe 4 main blood types

Answer 7

A - A antigens
B - B antigens
AB - A and B antigens
O - no antigens

Question 8

Outline concepts of compatibility and incompatibility between donor and recipient

Answer 8

A patient with blood group A can receive from a donor with blood group A (no B antigen) or blood group O (no antigens). However they can’t receive blood from a donor with blood group B or AB (B antigens present). B antigen may be attacked by persons immune system as it is a foreign antigen. Provokes an immune response.

Question 9

Outline the importance of the Rhesus factor in grouping blood during transfusion and during pregnancy

Answer 9

Rhesus controlled by RhD antigen
Rh+ is dominant over Rh-
If mother is Rh- and baby is Rh+ and blood mixes then mothers immune system will attack the baby’s blood cells as its antigens will be foreign to mothers body