Physiology of Blood Cells and Haematological Terminology Flashcards
21.10.2019
1
Q
Where do blood cells come from?
A
Multipotent haematopoietic stem cells in the bone marrow.
- > myeloid (megakaryocytes, erythroid, granulocyte-monocyte)
- > lymphoid (T,B, NK cells)
2
Q
What are some essential stem cell characteristics?
A
Ability to self-renew and produce mature progeny
3
Q
Normal erythroid maturation
A
- Myeloid stem cell
- proerythroblast
- early, intermediate and late erythroblast (division between each)
- erythrocyte
4
Q
What is the process of producing red cells called?
A
erythropoiesis
5
Q
What does normal erythropoiesis require?
A
- presence of erythropoietin
- synthesised mainly by the kidney in response to hypoxia
6
Q
Synthesis of erythropoietin
A
- 90% synthesised in juxtotubular interstitial cells in the kidney
- 10% made in the liver (hepatocyte and interstitial cells)
- erythropoietin reaches the bone marrow through circulation.
7
Q
RBC
A
- lifespan ~120d
- main function: Oxygen transport
- also transports som CO2
- ultimately destroyed by phagocytic cells of the spleen
8
Q
What is needed for the development of granulocytes and monocytes?
A
Cytokines such as G-CSF, M-CSF, GM-CSF and various interleukins are needed
9
Q
What are the different types of granulocytes?
A
- neutrophils
- basophils
- eosinophils
10
Q
Anisocytosis
A
red cells show more variation in size than is normal
11
Q
Poikilocytosis
A
red cells show more variation in shape than is normal
12
Q
Microcytosis
A
red cells are smaller than normal
13
Q
Macrocytosis
A
red cells are larger than normal
14
Q
Microcyte
A
a red cell that is smaller than normal
15
Q
Macrocyte
A
a red cell that is larger than normal
16
Q
Macrocyte types
A
- Round macrocytes
- Oval macrocytes
- Polychromatic macrocytes
=> determined by shape and staining
17
Q
Microcytic
A
describes red cells that are smaller than normal or an anaemia with small red cells
18
Q
Normocytic
A
describes red cells that are of normal size or an anaemia with normal sized red cells
19
Q
Macrocytic
A
describes red cells that are larger than normal or an anaemia with large red cells
20
Q
Normal paleness of RBCs
A
- Normal red cells have about a third of the diameter that is pale
- This is a result of the disk shape of the red cell; the centre has less haemoglobin and is therefore paler
21
Q
Hypochromia
A
- cells have a larger area of central pallor than normal
- results from a lower Hb content and concentration and a flatter cell
- RBCs that show hypochromia are described as hypochromic
22
Q
What does Hypochromia often go together with?
A
Microcytosis
-> often have the same cause, e.g. iron deficiency
23
Q
Hyperchromia
A
- cells lack central pallor
- can occur because they are thicker than normal or because their shape is abnormal
- cells showing hyperchromia can be described as hyper chromatic or hyperchromic
- the cells may be irregular in shape
- many causes since many abnormally shaped cells lack the central thinner area
24
Q
What cells do myeloblasts give rise to?
A
granulocytes
25
What cells do monoblasts give rise to?
Monocytes
26
G-CSF
granulocyte colony-stimulating factor
27
GM-CSF
granulocyte-macrophage colony-stimulating factor
28
M-CSF
macrophage colony-stimulating factor
29
Normal Granulocyte Maturation
- starts with myeloblast
- granules develop
- promyeloblast: primary granules, golgi zone (=clear area), extensive nucleus)
- same things happen in N, E and B pathway
- nucleus more condensed with maturation
30
How can you see how many immature RBC there are?
- look at blood stain for blue tinge and larger cells
| - specific reticulocyte stain - allows to count the reticulocytes
31
Neutrophil
- lifespan ~7-10h in circulaition before migrating to tissues
- main function: defence against infection
- phagocytosis and then kills microorganisms
32
Movement of neutrophils into tissues
1. adhesion and margination
2. rolling
3. diapedesis
4. migration
5. phagocytosis
Chemotaxis - attracted by chemokines
33
Eosinophils
- spends less time in the circulation than the neutrophil
| - main function: defence against parasitic infection
34
Basophils
- A myeloblast can also give rise to basophil granulocytes
- allergic responses
- takes up BASic dye
35
Monocyte
- spend several days in the circulation
- migrate to tissues where they develop into macrophages and other specialized cells that have a phagocytic and scavenging function
- store and release iron
- cytoplasm can contain a lot of debris
- nucleus of RBC precursor can be taken up by macrophage or takes up erythroblasts that die in the bone marrow
- larger than granulocytes
WHAT IS RELEASED FOT HAEMATOPOISES??
36
Platelet
- lifespan: ~10 days in circulation
- primary haemostasis
- contribute phospholipid, which promotes blood coagulation
37
What cells does the lymphoid stem cell give rise to?
- T, B, NK cells
- recirculate lymph nodes and other tissues and the back to the bloodstream
- intravascular life span variable
38
Where are oval macrocytes common?
- e.g. Vit B12 deficiency
39
Spherocytes
- approximately spherical in shape
- round, regular outline and lack central pallor
- result from the loss of cell membrane without the loss of an equivalent amount of cytoplasm so the cell is forced to round up
40
Hereditary spherocytosis
- not all cells are spherical
41
Hyperchromia - irregularly contracted cells
- irregular in outline
- smaller than normal cells
- have lost their central pallor
- usually result from oxidant damage to the cell membrane and to the haemoglobin
42
Polychromasia
- increased blue tinge to the cytoplasm of a red cell
| - indicates that the red cell is young
43
Reticulocytes and Reticulocytosis
- Another way to detect young cells: reticulocyte stain
| - exposes living red cells to new methylene blue, which precipitates as a network or ‘reticulum’
44
Polychromasia and reticulocytes
- Detecting polychromasia or increased numbers of reticulocytes gives you similar information
- identification of reticulocytes is more reliable so they can be counted
45
Types of poikilocytes
- Spherocytes
- Irregularly contracted cells
- Sickle cells
- Target cells
- Elliptocytes
- Fragments
46
Target cells
- cells with an accumulation of Hb in the centre of the area of central pallor
- occur in:
- jaundice
- liver disease
- hameoglobinopathies
- hyposplenism
47
Elliptocytes
- elliptical in shape
- They occur in hereditary elliptocytosis and in iron deficiency
- in iron deficiency they have a larger area of central pallor because of the hypochromia in iron deficiency anaemia; also microcytes can be found in iron deficiency
48
Sickle cell
- crescent / boat shaped
| - They result from the polymerisation of haemoglobin S when it is present in a high concentration
49
Fragments
- Fragments or schistocytes are small pieces of red cells
| - indicate that a red cell has fragmented
50
Rouleaux
- stacks of red cells
- resemble a pile of coins
- result from alterations in plasma proteins
- common finding in infection and inflammation
51
Agglutinates
- differ from rouleaux in that they are irregular clumps, rather than tidy stacks
- usually result from antibody on the surface of the red cells making RBCs clump together
52
Howell‒Jolly body
- red cells can also include remnants
- HJB: remnant of nucleus in RBC
- commonest cause: lack of splenic function (e.g. spelectomy or spleen atrophy)
53
Leucocytosis
too many white cells
54
Leucopenia
too few white cells
55
Neutrophilia
too many neutrophils
56
Neutropenia
too few neutrophils
57
Lymphocytosis
too many lymphocytes
58
Eosinophilia
too many eosinophils
59
Atipical Lymphocyte
- abnormal lymphocyte
- Often the term is used to describe the abnormal cells present in infectious mononucleosis (‘glandular fever’)
- ‘Atypical mononuclear cell’ is an alternative term
60
Left shift
- Left shift means that there is an increase in non-segmented neutrophils or that there are neutrophil precursors in the blood
- many less mature cells
- suggests infection and inflammation
- increase in non-segmented neutrophils
61
Toxic granulation
- heavy granulation of neutrophils
- results from infection, inflammation and tissue necrosis
- also a normal feature of pregnancy
62
Hypersegmented neutrophil
- increase in the average number of neutrophil lobes or segments
- usually results from a lack of Vit B12 or folic acid
- 6 or more lobes -> hypersegmentation
63
What are the 2 important types of hyperchromic cells?
- spherocytes
| - irregularly contracted cells
64
Why does hyperchromia have many causes?
many abnormally shaped cells lack the central thinner area
65
What is more reliable - polychrmasia or reticulocytes?
identification of reticulocytes is more reliable so so they can be counted
66
Thrombocytosis
Too many platelets
67
Thrombocytopenia
not enough platelets
68
Erythrocytosis
too many erythrocytes
69
Reticulocytosis
increased number of reticulocytes
70
Lymphopenia
not enough lymphocytes
| should mean not enough lymph, but means not enough lymphocytes
71
Reticulocyte
an immature red blood cell without a nucleus, having a granular or reticulated appearance when suitably stained.
72
Macrophages
= Monocytes in tissues
- phagocytic and scavenging role
- iron storage
73
How can macrophages store iron?
- ingest erythroblasts that die in the bone marrow
- macrophage breaks down iron (from Hb) -> synthesises ferritin, stores as hemosiderin
- iron can be released when needed for erythropoises in the bone marrow
74
How can macrophages store iron?
- ingest erythroblasts that die in the bone marrow
- macrophage breaks down iron (from Hb) -> synthesises ferritin, stores as hemosiderin
- iron can be released when needed for erythropoises in the bone marrow
75
Pencil cell
long thin elliptocye
76
Pencil cell
long thin elliptocye
77
Hereditary elliptocytosis
- hereditary disorder of red cell membrane
| - elliptical cells
