Blood And Blood Components Flashcards
What is blood made of?
55% plasma
45% red blood cells
< 1%% white blood cells
<1% platelets
How much blood in a pregnant woman and newborn?
Newborn = between75 to 80 ml of blood
Pregnant woman = 5-6 litres
(Pregnant women tend to nave higher blood pressure due to having more blood)
RBC
- Biconcave discs - flexible membrane
- carry haemoglobin
- carry some Co2
-. Lack nucleus and organelles - specialised cells so cannot reproduce by mitosis
How are red blood cells made?
Starts in bone marrow
Differentiates into pro erythroblast
Haemoglobin is made and nucleus is removed
Reticulocyte matures after leaving bone marrow = erythrocyte
White blood cells
Have a nucleus, can live for months/years, combat infection by phagocytosis and can leave blood stream to deal with invading pathogens.
Platelets
Disc shaped
No nucleus
5-9 day lifespan
Blood groups
Surface of erythrocytes have genetically predetermined coating of glycoprotein and glycolipids. These act as antigens. Blood group is categorised by presence of antigens on the cell surface.
What are the blood groups?
A, B, AB, O
A and B are dominant to O
A and B are codominant
Rhesus blood group
3 inherited alleles responsible for coding for rhesus antigen: C, D, E
D antigen responsible for rhesus status of an individual
Rh+ is dominant to Rh -
Blood transfusion
A blood can only transfuse with A
B can only transfuse with
AB can transfuse with any
O can only transfuse with O
What is ABO incompatibility in pregnancy?
Happens when mother’s blood type is o and baby is A or B. Mother’s immune system may react and make antibody against beeby’s RBC
What is rhesus incompatibility in pregnancy?
Occurs when mother is Rh neg and baby is Rh pos. Rh D antigen from foetus mix with mother’s blood which causes her to make anti D antibodies which attack foetal erythroastes. Causes ISO - immunisation and anaemia and may lead to jaundice in first 48 hours.
