1: Haemopoiesis Flashcards
What is haemopoiesis?
Production of blood cells
What is the average life span of a red blood cell?
120 days
What is the average life span of a platelet?
7 - 10 days
What is the average life span of a neutrophil?
7 - 8 hours
If the bone marrow is suppressed, which blood cells become deficient first?
Why?
Neutrophils
Shortest life span
Which type of blood cell is polyploid?
Megakaryocytes
What is unique about the cell division of haemopoietic stem cells?
Capacity for self renewal
One of the daughter cells with be a HSC identical to its mother cell
So they can divide forever
What is meant by myeloid?
Re: malignancy - a bone marrow malignancy
Re: lineage - non-lymphoid i.e granulocytes and lymphoid cells
Which germ layer do HSCs originate from?
Mesoderm
By which week of life does bone marrow haemopoiesis start?
Week 16
In children, which areas of bone marrow undergo haemopoiesis?
All of the bone marrow
In adults, which areas of bone marrow undergo haemopoiesis?
Axial skeleton
Pelvis
Proximal long bones only
From which site is a bone marrow biopsy carried out in
a) adults
b) children?
a) PSIS
b) Anterior tibia
Apart from haemopoietic cells, what other cells exist in the bone marrow?
Fat cells
Osteoblasts
Osteoclasts
Fibroblasts
Through which structures in bone marrow are newly produced blood cells released?
Sinusoids
Blood enters the bone marrow via ___.
Blood cells enter the plasma, then the plasma re-enters the circulation via ___.
capillaries
sinusoids
What is special about the basement membrane of bone marrow sinusoids?
Discontinuous
Allows blood cells to enters the plasma
What are the gaps in the basement membrane of a bone marrow sinusoid called?
Fenestrations
Bone marrow sinusoids have adventitial cells - what are the function of these cells?
Contain smooth muscle - dilate and constrict to increase/decrease blood flow
What colour is
a) active
b) fatty, inactive bone marrow?
a) Red
b) Yellow
What is the myeloid:erythroid ratio?
Ratio of neutrophils (and precursors) to red blood cell precursors
The myeloid:erythroid ratio usually favours (myeloid / erythroid) cells.
myeloid cells
i.e more neutrophils than RBCs
In which situation is the myeloid:erythroid ratio reversed?
Blood loss
Haemolysis
i.e situations demanding erythropoiesis
What is the only way to figure out the type of lymphocyte you’re looking at on a blood film?
Immunophenotyping
looking at specific antigens expressed on their cell membrane
