Haematopoiesis Flashcards
What is haematopoesis?
The generation of all blood cells from precursor cells.
What fraction (%) of the blood is plasma?
50-60%
What does PCV stand for when talking about components of blood? What is its other name? What cells does it consist of? What fraction (%) of blood is PCV?
Packed cell volume
Also called hematocrit
It is red blood cells and makes up around 40% of blood volume.
What makes up the ‘Buffy coat’ dividing hematocrit from plasma?
White blood cells (leukocytes) and platelets.
Name the X3 types of blood cells and state where they spend their time.
Erythrocytes (RBC’s) - confined to blood vessels
Platelets - confined to blood vessels
Leukocytes (WBC’s) - in transit from blood vessels to and from tissues
What are the main sites of haematopoesis?
The larger bones centrally located, from superior to inferior both in organisation and amount of haematopoesis.
Vertebra and pelvis
Sternum
Ribs
Femur
What is a totipotent stem cell?
Can form a complete organism.
What is a pluripotent stem cell?
Can form any type of body cell.
What is a multipotent stem cell?
Can divide into multiple but restricted cell types.
What is a unipotent stem cell?
Can only produce 1 type of cell.
Complete the following:
________ stem cell ——> ________ cells ——> differentiated blood cells
Multipotent
Progenitor
Where does the process of haematopoesis occur?
In the bone marrow, but fully matured cells are only found in the blood vessels or tissues.
Which artery is the main blood supply to the bone marrow?
The nutrient artery.
In which cavity does the bone marrow sit?
The medullary cavity.
Where does haematopoesis occur in relation to the blood vessels in the medullary canal?
It occurs between the vasculature, in the extra vascular spaces between the medullary sinuses.
What is the average lifespan of an RBC?
120 days.
Which organs remove old RBC’s?
The spleen and the liver.
What are the penultimate and last precursors of a mature RBC?
A normoblast and a reticulocyte.
What is another name for platelets?
Thrombocytes, formed from fractionated Megakaryocytes.
What is the lifespan of a platelet?
8-12 days.
Platelets are fragments of Megakaryocytes, but what is the name of the channels which separate sections of the megakaryocyte into vesicles ready to be fragmented off.
Platelets demarcation channels.
What is the most abundant type of leukocyte?
Neutrophils.
What is chemotaxis?
The movement of an organism towards a gradient of chemokines (chemicals).
What does a monocytes look like?
Mono-nucleic
No granules
Kidney shaped nucleus
What does a lymphocyte look like?
Mono-nucleic
No granules
Nucleus spherical + taking up most of cell
What does a neutrophil look like?
Multi-lobed nucleus (lots of lobes).
What does a basophil look like?
Bi-lobed nuclei (horseshoe)
Lots of dark blue granules
What does an eosinophil look like?
Bi-lobed nucleus (horseshoe)
Lots of dark red granules
What are the names of the functional arms extending from neutrophils to aid motility in chemotaixs?
Pseudopods @ front
Uropods @ back
