Blood cell histology and investigations Flashcards
What percentage of blood is plasma and cells?
Plasma – 55%
Cells – 45%
Name 4 things which plasma contains.
Water
Small organic compounds
Electrolytes
Proteins
What are platelets (thrombocytes)?
Small, disc-shaped cell fragments
What is haematopoiesis?
The process by which blood cells are made
All blood cells arise from what?
Haematopoietic stem cells
Describe the potency of haematopoietic stem cells.
Multipotent
What is stem cell potency?
The potential of stem cells to differentiate and develop into many different types of specialized cells
Name the 5 types of stem cell potency.
Totipoten
Pluripotent
Multipotent
Oligopotent
Unipotent
What can totipotent cells differentiate into?
Any cell type, including embryonic and extraembryonic
Give an example of a totipotent cell.
The zygote (fertilized egg) and the early blastomeres resulting from the first few cell divisions of the zygote
What can pluripotent cells differentiate into?
Nearly all cell types but not extraembryonic tissues like the placenta
Describe the potency of lymphoid and myeloid stem cells.
Oligopotent
Describe the site of haematopoiesis in 0-3 months gestation.
Yolk sac
Describe the site of haematopoiesis in 3 months gestation.
Liver and, to a much lesser extent, the spleen
- Describe the site of haematopoiesis in 4 months gestation.
Bone marrow
What are the 2 types of bone marrow?
Red marrow and yellow marrow
Yellow marrow is composed predominantly of what?
Fat cells
What happens to red bone marrow as we age?
It’s converted to yellow marrow
By the age of 30, red bone marrow is only found in which 5 places?
Cranial bones
Sternum
Ribs
Vertebrae
Pelvis
Describe the composition of red blood cells.
30-35% haemoglobin
60-65% water
What are the 2 benefits of the biconcave shape of RBCs?
Maximizes the surface-volume ratio and so facilitates the exchange of O2 and CO2
Increases cell flexibility, making it easier for cells to pass through the capillaries
What colour do basophils stain? Which compound causes this?
Deep blue – haematoxylin
What needs to be added to a blood sample and which colour test tube should be used if you need to look at the cellular components of blood?
An anticoagulant – EDTA, in a purple top tube
If serum wants to be looked at, what colour tube should be used?
Gold top tube
What is a reticulocyte?
An immature red blood cell
How is MCH calculated?
Haemoglobin over RBC count
How is MCV calculated?
Haematocrit over RBC count
