Physiology of Blood Cells and Haematological Terminology Flashcards
Where do all RBCs originate?
Bone marrow
From what do RBCs derive from?
Derived from MULTIPOTENT haemopoietic stem cells
The multipotent stem cells give rise to:
o lymphoid stem cells
o myeloid stem cells - from which RBCs, granulocytes, monocytes & platelets are derived
Essential characteristics of stem cells?
SELF-RENEW whilst producing mature progeny
by dividing into:
o another stem cell
AND
o a mature cell
Pathway of Erythrocyte production
- Multipotent myeloid stem cell
- Proerythroblast
- Erythroblast
- Erythrocyte
Erythropoiesis?
Process of PRODUCING RBCs
What is required for erythropoiesis to occur?
Erythropoietin presence
This is mainly synthesised in the KIDNEY is response to HYPOXIA
How is Erythropoietin synthesised?
90% - Juxtatubular Interstitial Cells of the KIDNEY
10% - Hepatocytes & Interstitial Cells of the LIVER
Characteristics of RBCs?
o survive around 120 days
o main function is O2 transport
(but also transports CO2)
o destroyed by phagocytes in spleen
Along with a proerythbrolast, what else can a multipotent myeloid stem cell give rise to and what is needed for this?
Myeoblast & monoblast
which in turn gives rise to:
o granulocytes
o monocytes
Cytokines/ILs are required for this
i.e. G-CSF, M-CSF, GM-CSF
G-CSF, GM-CSF and M-CSF?
CSF = colony-stimulating factor
G = granulocyte M = macrophage
4 main granulocytes?
o Neutrophil
o Eosinophil
o Basophil
o Mast cells
Characteristics of neutrophils?
o survives 7-10 hrs in circulation BEFORE migrating to tissue (roll & migrate mechanism)
o Defence agaisnt INFECTION - phagocytoses and kills
Diagram of a neutrophil?
(look at OneNote!)
Characteristics of eosinophils?
o spends LESS time in circulation than a neutrophil
o Defence agaisnt PARASITIC INFECTION
Diagram of a eosinophil?
(look at OneNote!)
Characteristics of basophil?
o Role if ALLERGIC reactions
Diagram of basophil?
(look at OneNote!)
Characteristics of monocytes?
o spend SEVERAL DAYS in circulation - migrate to tissues where they develop into MACROPHAGES & other specialised cells that have a phagocytic function
o STORE & RELEASE IRON
o PHAGOCYTOSE bacteria, fungi & dead tissue
Diagram of monocyte?
(look at OneNote!)
Characteristics of platelets?
o Multipotent haematopoietic stem cells also give rise to megakaryocytes = platelets
o survive 10 DAYS in circulation
o Have a role in 1o haemostasis - contribute phospholipid to promote blood coagulation
Diagram of platelet?
(look at OneNote!)
Characteristics of lymphocytes?
o Lymphoid tissue (from M.H SCs) give rise to T, B & NK cells
o Recirculate to lymph nodes and other tissues - then back to bloodstream
o Lifespan intravascular is VERY VARIABLE
Diagram of lymphocyte?
(look at OneNote!)
Anisocytosis?
RBCs shows MORE VARIATION in SIZE than is normal
Poikilocytosis?
RBCs show MORE VARIATION in SHAPE than is normal
Images on blood film/counts to show anisocytosis & poikilocytosis?
(look at OneNote!)
Microcytosis?
RBCs are SMALLER than normal
Macrocytosis?
RBCs are LARGER than normal
Images on blood film/counts to show microcytosis & macrocytosis?
(look at OneNote!)
What are the specific types of macrocytes?
- Round macrocyte
- Oval macrocyte
- Polychromatic macrocyte
How do the 3 types of macrocytes look?
(look at OneNote!)
What are the 3 broad categories of anaemia?
- Microcytic
- Normocytic
- Macrocytic
Microcytic anaemia?
RBCs that are SMALLER than normal
i.e. anaemia w. SMALL RBCs
Normocytic anaemia?
RBCs that are on normal size
i.e. anaemia w. NORMAL sized RBCs
Macrocytic anaemia?
RBCs that are LARGER than normal
i.e. anaemia with LARGE RBCs
Diagram of macrocytic anaemia?
(OneNote - anisocytosis image)
Hypochromia?
When the RBCs have a LARGER AREA of CENTRAL PALLOR than normal!
Normal RBCs have 1/3 diameter that is pale (this gives rise of the disc shape as the centre has less Hb)
Why are RBCs hypochromic?
Due to a LOWER Hb content and concentration, giving rise to a flatter cells
What normally goes hand-in-hand with hypochromia?
Microcytosis!
Hyperchromia?
RBCs LACK CENTRAL PALLOR
This can be either:
o as they are THICKER than normal
OR
o their shape is ABNORMAL
Hyper vs. Hypo chromia?
Hyper - LACK central pallor
Hypo - LARGE central pallor
2 important types of cells in hyperchromia?
o Spherocytes
o Irregularly contracted cells
Diagram of spherocytes & irregularly contracted cells?
(OneNote!!)
Spherocytes?
o approx. spherical in shape SO have a round, regular outline
o LACK central pallor
Due to LOSS of cell membrane WITHOUT the equivalent loss of cytoplasm SO cell FORCED to ROUND UP
Disease resulting in spherocytes?
Hereditary spherocytosis
Irregularly contracted cells?
o Irregular in outline BUT are SMALLER than normal cells
o LOST their central pallor
Usually arise sue to oxidant damage to the cell membrane and Hb
Polychromasia?
INCREASED
BLUE TINGE
to the cytoplasm of a RBC
Indicates that the RBC is YOUNG
How can you detect young cells in a blood film?
Do a RETICULOCYTE STAIN
Exposes living RBCs to methylene blue which precipitates the network seen inside the cells - should only have 1-2% of these cells in population ciruclating
Polychromasia vs. reticulocyte staining - which is preferred?
Identification of reticulocytes is MORE reliable
What variety of shapes do poikilocytes come in?
o Spherocytes o Irregularly contracted cells o Sickle cells o Target cells o Elliptocytes o Fragments
Target cells?
Have as accumulation of Hb in the CENTRE of the area of central pallor
Occurs in: o obstructive jaundice o liver disease o haemoglobinopathies o hyposplenism
Elliptocytes?
Elliptical in shape (elongated circle, stretched into an oval)
Occurs in:
o elliptocytosis
o iron deficiency
(OneNote!!!!)
Sickle cells?
Sickle/crescent shaped
Result from the polymerisation of HbS chains when it is present in [HIGH]
Fragments?
Small pieces of RBCs
Indicate RBCs have been fragmented - could be due to:
o abnormal stress on RBC
OR
o if cell is intrinsically abnormal
Another name for fragments?
Schistocytes
Roleaux?
STACKS of RBCs (resemble pile of coins)
Result due to ALTERATIONS in plasma proteins
Agglutinates?
Irregular clumps
Result from ABs on the surface of the cells
Difference between roleaux & agglutinates?
Agglutinates are IRREGULAR clumps
rather than TIDY stacks
(OneNote!!!)
Howell-Jolly Body?
Nuclear remnamt in a RBC
Commonest cause is LACK of splenic function
-cytosis/philia vs. -penia?
- cytosis/philia - too MANY
- penia - too FEW
Thrombo-?
In regards to PLATELETS
What are atypical lymphocytes?
An abnormal lymphocyte
Often used to describe abnormal cells in infectious monoculeosis
What is meant by ‘Left shift’?
There is an:
o INCREASE in non-segmented neutrophils
OR
o that there are neutrophil precursors in the blood
(i.e. left to right = NORMAL but right to left is NOT [onenote!!])
Toxic granulation?
HEAVY granulation of neutrophils
Results from:
o infection
o inflammation
o tissue necrosis
In what normal condition can toxic granulation be seen?
Pregnancy - a feature of it
Hypersegmeneted neutrophils?
INCREASE in the average no. of neutrophil lobes or segements
Usually sue to lack of Vit.B12 OR folic acid!