Normal Haemopoiesis

Question 1

Define Haemopoiesis.

Answer 1

Formation of blood cells. Occurs mainly in bone marrow.

Question 2

In adults, normal haemopoiesis forms…

Answer 2

Skull. Vertebrae. Ribs. Scapulae. Iliac crest.

Question 3

In children, normal haemopoiesis forms…

Answer 3

All skeletal bones.

Question 4

Define Myelopoiesis.

Answer 4

Multipotent HSC can differentiate into multipotent progenitors (MPP).

Question 5

Define myeloid progenitors e.g. granulocytic cells.

Answer 5

Eosinophils. Neutrophils. Basophils. Mast Cells.

Question 6

Define Erythropoietin.

Answer 6

Necessary for all stages of red cell development.

Question 7

When is Erythropoietin mainly produced?

Answer 7

Mainly produced by kidney in response to hypoxia. Red cell nucleus lost, before reticulocyte and mature erythrocyte stages.

Question 8

Define Thrombopoiesis.

Answer 8

Haemopoietic stem cells (HSCs) can differentiate into megakaryocyte-erythroid progenitors (MEPs) - then megakaryocytes, platelets.

Question 9

Thrombopoietin (TPO), interleukin (IL-6) and other cytokines stimulate…

Answer 9

Maturation of megakaryocytes.

Question 10

Which organ produces Thrombopoietin (TPO)?

Answer 10

Liver.

Question 11

Define Lymphopoiesis.

Answer 11

Common lymphoid progenitors, with both B and T cell potential, originate in the bone marrow.

Question 12

Where are B lymphocytes formed?

Answer 12

Bone marrow. Migrate to secondary lymphoid tissue e.g. lymph nodes, mucosa-associated lymphoid tissue (MALT), spleen.

Question 13

What process results in the proliferation and differentiation of activated B lymphocytes into plasma cells?

Answer 13

Somatic hypermutation.

Question 14

What are Natural Killer Cells?

Answer 14

Cytotoxic lymphocytes that do not express T cell receptors. Kill virally infected cells and tumour cells without differentiation.

Question 15

State a feature of a Red Cell.

Answer 15

Mature red cell in blood - lost its nucleus. Biconcave shape with large surface area for O2 exchange. Lack of organelles means red cell is flexible and easily deform to pass through capillaries and splenic sinusoids. Haemoglobin. Uptake of oxygen from lungs and delivery to tissues.

Question 16

State 2 white blood cells.

Answer 16

Lymphocytes. Neutrophils. Monocytes. Basophils. Eosinophils. Dendritic cells.

Question 17

State a feature of neutrophils.

Answer 17

Circulate in blood before migrating to tissues. Lifespan in blood of around 7-10hrs and in tissues 1-2 days.

Question 18

What colour do neutrophils stain with May-Grunulalde?

Answer 18

Lilac.

Question 19

State a function of Neutrophils.

Answer 19

Margination (adhesion of white blood cells of walls of damaged vessels). Adhesion to endothelium. Killing and digestion of microorganisms. Phagocytosis and digestion of dead cells and cellular debris.

Question 20

State a feature of Eosinophils.

Answer 20

Larger than neutrophils. Nucleus is usually bi-lobed. On MGG - stained orange/brick red. Synthesise and secrete growth factors, cytokines and chemokines. Trigger the release of histamine by basophils and mast cells (control infection by parasites). Attack parasites by degranulation and peroxidase-mediated generation of reactive O2 species.

Question 21

State a feature of Basophils.

Answer 21

On MGG-stained films (dark purple). Nucleus bilobed. Cytoplasm contain scattered glycogen particles, golgi and few mitochondria. Involved in allergy, anaphylaxis and chronic inflammation.

Question 22

What colour are Monocytes stained?

Answer 22

MGG stain - opaque greyish-blue.

Question 23

State a function of Monocytes.

Answer 23

Phagocytosis and killing of microorganisms e.g. mycobacteria, listeria and fungi. Antigen-presenting cells. Immune modulator - secrete IL-1, IL-6, IL-12, tumour necrosis factor, interferon alpha and beta.

Question 24

Lymphocytes can be divided into which cells…

Answer 24

B cells. T cells. Natural killer (NK) cells.

Question 25

State the 3 types of haematological malignancies.

Answer 25

Myeloid. Lymphoid. Dendritic.

Question 26

State 3 types of Myeloid Malignancies (arise from different stages of myeloid maturation).

Answer 26

Myeloproliferative neoplasms. Myelodysplastic neoplasms. Acute myeloid leukemia.

Question 27

State 3 types of lymphoid neoplasms.

Answer 27

B, T and Natural Killer Cells.

Question 28

Define chronic myeloid leukemia.

Answer 28

Arise from haemopoietic stem cell. Always associated with BCR-ABL1 fusion gene due to t(9,22) Philadelphia’s chromosome.

Question 29

State a clinical feature of chronic myeloid leukemia.

Answer 29

Elevated white cell count. Fatigue, malaise, weight loss, night sweats. Splenomegaly. WBC > 50,000 - immature myeloid cells, basophils, eosinophils.

Question 30

Define the prognosis of CML.

Answer 30

Transformed into 5yr survival of over 90%. PCR-based tests - used for monitoring response to treatment and diagnosing treatment failure. Tests are available to detect mutations within BCR-ABL gene.