Blood Cell Science Flashcards
Define Haematology
- study of the cellular components found in the blood & their interactions with plasma proteins or other cells in the body
What are the functions of Red Blood Cells ?
- mature red cells contian the haemoglobin for the transportation of oxygen to the tissues
Describe the structure of RBC’s
- biconcave
- high SA to volume ratio
- red cell is deformable - has a diameter of 6um but can squeeze through capillaries of 2um
What’s the ref range for RBCs for men ?
4.4 - 5.8 x 10^12 /L
What’s the ref range for RBCs for women ?
4.1 - 5.2 x 10^12 /L
Where are red cells produced?
- During Gestation
- During Infancy
- During Adulthood
Describe RBC production during gestation
- Yolk sac is main site
- after 3rd month foetal life this moves to the liver and spleen
- liver & spleen can be predominant site until 2 weeks post birth
- stem cells in foetal bone marrow start producing 5-9 months
Describe RBC production during infancy
- all bone marrowis haemopoietic
- as child grows older there is a fatty acid replacement of marrow in long bones
Describe RBC production in adulthood
- confined to ribs,vertebrae, skull, pelvis & iliac crest
- involves a pluripotent stem cell
Describe a Totipotent Stem Cell
- unlimited capability and have the ability to form extraembryonic membranes & tissues - as wells as the embryo itself
- also post embryonic tissues & organs
Describe a Pluripotent Stem Cell
these cells are capable of giving rise to most, but not all, tissues of an organism
- also capable of self renewal
Describe a multipotent stem cell
these cells are comitted to give rise to cells that have a specific function
What can result from Pluripotent stem cells ?
- Lymphoid stem cell
- Multipotent stem cells (which give rise to the myeloid series)
What factors effect RBC development ?
- microenvironment of stem cells
- erythropoietin
- cytokines
Describe Erythropoietin
- hormone produced in kidney
- regulated by oxygen tension in renal tissues
- anaemia = increased erythropoietin
What are the actions of Erythropoietin ?
- increase number of cells committed to RBC production
- increased haemoglobin synthesis
- decreased maturation time of red cells
Decribe Cytokines
- peptides that normally bind to a receptor to initiate cell signalling
- end point is either cell division or differentiation
- examples = interleukins & colony stimulation factors
Describe what happens to Reticulocytes
- leave the bone marrrow & enters the bloodstream
- stay in the spleen/liver for 24hrs until they mature
Describe immature red cells
- reticulocytes
- stain dark purple - called polychromasia
- if they stain with new methylene blue = reticulocytes
