Basics of Haematology

Question 1

Components of Blood

Answer 1

Plasma, buffy coat and red blood cells

Question 2

Plasma

Answer 2

Clotting or coagulation factors, albumin, antibodies

Question 3

Buffy coat

Answer 3

Platelets, white cells or leucocytes

Question 4

Functions of Blood (Transport)

Answer 4

Red blood cells transport oxygen and carbon dioxide.

Plasma transports nutrients, waste and messages??

Question 5

Functions of Blood (Maintenance of Vascular Integrity)

Answer 5

Prevention of leaks (platelets and clotting factors)

Prevention of blockages (anticoagulants and fibrinolytics)

Question 6

Functions of blood (prevention of pathogens)

Answer 6

Phagocytosis and killing (granulocytes and monocytes)

Antigen recognition and antibody formation (lymphocytes)

Question 7

Haematopoisesis

Answer 7

The process whereby blood cells are made. Pluripotent haematopoietic stem cell to uncommitted stem cells and lymphocyte stem cells (lymphocytes). These can become erythroblasts (erythrocytes), megakarycytes (platelets), myeloid cells (neutrophil, monocyte, basophil)

Question 8

Stem cells

Answer 8

These are totipotent and undergo self-renewal.

Question 9

Home to marrow niche

Answer 9

CXCR4 (antagonist plerixafor)

Question 10

Bone marrow

Answer 10

Present in the bones. Stroma and sinusoids.

Question 11

Erythroid Differentiation

Answer 11

Erythroblast - reticulocyte - erythrocyte

Question 12

Erythropoietin

Answer 12

Made in the kidney in response to hypozia

Question 13

Reticulocyte count

Answer 13

A measure of red cell production

Question 14

Consequences of anaemia

Answer 14

Poor gas transfer resulting in dyspnoea and fatigue.

Question 15

What causes anaemia

Answer 15

Decreased production of red cells due to deficiency in haematinics (iron, folate and vitamin B12) or thalassaemia (any of a group of hereditary haemolytic diseases caused by faulty haemoglobin synthesis)

Increased loss due to bleeding or haemolysis

Question 16

Red Cells

Answer 16

microcytes (an unusually small red blood cell, associated with certain anaemias)

Macrocytes (A macrocytic class of anemia is an anemia (defined as blood with an insufficient concentration of hemoglobin) in which the red blood cells (erythrocytes) are larger than their normal volume)

Burr cells (echinocytes) abnormal cell membrane characterized by many small, evenly spaced thorny projections

Question 17

Function of platelets

Answer 17

Haemostasis and immune function.

Question 18

Production of platelets is regulated by

Answer 18

Thrombopoietin which is produced in the liver, regulated by platelet mass feedback. Lifespan is 7 days.

Question 19

Function of neutrophils

Answer 19

To ingest and destroy pathogens, especially bacteria and fungi

Question 20

Regulation of neutrophols

Answer 20

Macrophages and Interleukin

Question 21

Life span of neutrophils

Answer 21

1-2 days

Question 22

Neutrophil differentiation

Answer 22

Blast cells, promyelocyte, myelocyte, metamyelocyte and neutrophil

Question 23

Neutrophilia

Answer 23

Raised neutrophils caused by infection (G-CSF) and inflammation

Question 24

Neutropenia

Answer 24

Decreased neutrophil production due to drugs or marrow failure

Increased consumption (sepsis or autoimmune)

Altered function (chronic granulomatous disease)

Question 25

Monocytes function

Answer 25

To ingest and destroy pathogens. Subset of monocytes migrate into tissues to become macrophages or dendritic cells.

Question 26

Monocytosis

Answer 26

Usually associated with neurophilia. Due to mycobacterial infection

Question 27

Monocytopenia

Answer 27

Mycobacteria in hairy cell leukaemia

Question 28

Other myeloid cells

Answer 28

Eosinophils and basophils

Question 29

Lymphocytes

Answer 29

these are adaptive rather than innate. They have immunological memory. Surface antigens: CD markers.

Question 30

Lymphocytosis

Answer 30

Infectious mononucleosis and pertussis

Question 31

Lymphopenia

Answer 31

Lymphoma or post-viral

Question 32

Sub types of lymphocytes

Answer 32

B cells T cells – Helper, cytotoxic, regulatory NK cells

Question 33

Where are lymphocytes produced

Answer 33

B cells mature in bone marrow, T cells in thymus

Question 34

Antibodies

Answer 34

``` Adaptors between pathogens and clearance systems ‘Kiss of death’ Opsonisation Fix complement Block binding ```

Question 35

Combinatorial diversity

Answer 35

Any V-region combined with any J or D-region then C-region

Question 36

Junctional Diversity

Answer 36

At any join, additional nucleotides added by enzyme (terminal deoxynucleotidyl transferase, TdT)

Question 37

Combinatorial diversity between chains

Answer 37

Each alpha chain pairs with a beta chain | Each light chain pairs with a heavy chain

Question 38

Selection of B cells in the bone marrow

Answer 38

if gene rearrangement results in a functional receptor the cell is selected to survive – positive selection If the receptor recognises ‘self’ antigens - the cell is triggered to die – negative selection

Question 39

Human Leucocyte Antigen Class 1

Answer 39

Displays internal antigens on all nucleated cells

Question 40

HLA Class 2

Answer 40

Displays antigens eaten by professional antigen presenting cells

Question 41

Diagnostic tools of blood disorders

Answer 41

FBC, Clotting times, bleeding times for platelets, chemical assays (iron, B12, folate), marrow aspirate and trephine biopsy, lymph node biopsy, imaging

Question 42

Haematology Treatments (Replacement)

Answer 42

Blood Haematinics Coagulation factors Plasma exchange

Question 43

Haematology Treatments (Drugs)

Answer 43

``` Cytotoxics Monoclonal antibodies Inhibitors of cellular proliferation Immunosuppressants Inhibitors of coagulation Inhibitors of fibrinolysis ```

Question 44

Hypersplenism

Answer 44

Pancytopenia (deficiency of all three cellular components of the blood (red cells, white cells, and platelets).

Question 45

Hyposplenism

Answer 45

Infections with encapsulated bacteria, red cell changes

Question 46

Splenomegaly

Answer 46

``` Infectious -acute eg EBV, CMV -chronic bacterial eg TB, brucella, SBE -chronic parasitic eg malaria, leishmaniasis, schistosomiasis ``` Haematological-malignant - various leukaemias and lymphoma - myeloproliferative disorders Portal hypertension Haemolytic disorders -hereditary spherocytosis, thalassaemia, megaloblastic anaemia, autoimmune Connective tissue disorders - SLE - Felty Syndrome