Red Blood Cells and White Blood cells Flashcards
Hemopoesis
the production of blood cells and platelets, which occurs in the bone marrow
Where does haemopoiesis take place?
- In adults haemopoiesis is confined to the bone marrow
- In embryonic life and early infancy it can occur in other sites
Haematocrit
the volume of red blood cells i.e haemoglobin in the blood, normal haematocrit is 0.45
Problems with RBC
Anaemia-Hypoxia
hypo-regenerative vs. hyper-regenerative
reduced production vs. increased destruction
corpuscular (membrane proteins, haemoglobin, enzymes) vs. extra-corpuscular (increased destruction, reduced production, redistribution)
Blood has two phases
Cellular component (45%)
Red cells (form 99% of blood cells), white cells & platelets
Fluid component (55%); Plasma
Plasma without clotting factors is called serum
How much blood do we contain?
5 Litres
Primitive cells
The most primitive cells are stem cells; can be pluripotent (haematocytoblast are primitive o blood cells) - can differentiate into red blood cells, white blood cels and platelets
In the bone marrow the primitive cells (stem cells) proliferate and differentiate into mature cells
Red blood cell lifetime
120 days (make 2 million a second)
RBCs stimulating hormone, produced by the kidney, is called erythropoietin
This hormone influences formation of red blood cells
Platelets lifetime
7-10 days
red blood cells & platelets are anucleate (have no nucleus)
White blood cells lifetime
6 hours
Location of precursor cells of red blood cells
The precursor cells of red blood cells are located in the bone marrow:
- In adults this is in the axial skeleton - skull, ribs, spine, pelvis and long bones - In children this is in all bones
- In utero this is in the yolk sac, then liver and spleen
Precursor cells are not found in blood (if they are this is a sign of leukaemia)
Hormonal growth factors stimulate precursor stem cells to proliferate and differentiate:
- Epo/ Erythropoietin (hormone made in kidney) = red blood cells
- G-CSF (granulocyte colony stimulating factor) = white cells
- Thrombopoietin = platelets
What happens to the O2 dissociation curve when pH is decreased or when temperature is increased?
Shifts to the right
What happens to the O2 dissociation curve when pH is increased or when temperature is decreased?
Shifts to the left
Why do cells with no nucleus or mitochindria have a short lifespan?
They can not repair themselves
What is a Reticulocyte?
Young red blood cell
What do red blood cells consist of?
membrane to enclose Haemoglobin, otherwise the haemoglobin would clog up the kidneys if allowed into the blood on its own
enzymes of glycolysis
Haemoglobin - to carry oxygen
Function of Haemoglobin
Carries oxygen from the lungs to tissues, where it transfers oxygen to myoglobin in muscles
What does Haemoglobin consist of?
the protein haemoglobin, oxygen binds to the Fe 2+ in haem reversibly
Structure of Haemoglobin
is formed of 2 alpha and 2 beta chains and 4 haem groups
In fetus: 2 alpha and 2 gamma (gamma have a higher affinity for oxygen as fetus is codependent so needs higher affinity)
Has an overall quaternary structures - due to the combination of more than two tertiary structures
BLOOD TYPE & TRANSFUSIONS
Some people have the gene that results in the synthesis of the A antigen on the surface of red blood cells, some have the gene that results in the synthesis of the B antigen, some have both genes and some have neither.
Those who have neither are said to have O-type erythrocytes.
Thus the possible blood types are A (more common than B), B, AB (most rare) & O (most common)
Type A
individuals always have anti-B antibodies in their plasma.
A ANTIGEN IS CO-DOMINANT
Type B
individuals always have anti-A antibodies in their plasma.
B ANTIGEN IS CO-DOMINANT
Type AB
have neither anti-A or anti-B antibodies in their plasma, has A + B antigens on surface of red blood cells - UNIVERSAL RECIPIENT
Type O
have both anti-A & anti-B antibodies ( has no A or B antigens) in their plasma [type O is a UNIVERSAL DONOR since don’t have A or B antigens on surface of red blood cell]
O antigen is RECESSIVE