W1 Lec 5- The bone marrow

Question 1

What is hemapoiesis?

Answer 1

formation of blood cells

Question 2

Define granulopoiesis

Answer 2

formation of granules

Question 3

What is the formation of platelets called?

Answer 3

megakaryopoiesis or
thrombopoiesis

Question 4

Blood cell synthesis not included in hematopoiesis

Answer 4

lymphopoiesis

Question 5

Where does hemapoiesis take place?

Answer 5

bone marrow of the spongy bone (callus)

Question 6

What is the blood supply in the bone called?

Answer 6

Sinusoid

Question 7

Lists stages of RBC maturation

Answer 7

-Erythroblast»Normoblast»Polychromasia (mature erythocyte)

Question 8

List stages of Neutrophil maturation

Answer 8

Blast»Promyelocyte»myelocyte»metamyelocyte»Band cell»mature neutrophil

Question 9

Explains the process from megakaryocyte to platelets

Answer 9

• Megakaryocyte has a large nucleus with granules all over the cytoplasm
• The large nucleus is a result of endomitosis
• Pseudopod formation
• Megakaryocyte extend long cytoplasmic protrusions called proplatelets into the bone marrow sinusoids
• Extended proplatelets undergo fragmantation, which is the breakdown of proplatelets into smaller platelets
• As the proplatelets fragment, these granules are released into the blood stream forming the platelets we recognise.

Question 10

Other cells in the bone marrow

Answer 10

lymphocytes, plasma cells,
macrophages, fat cells

Question 11

What is marrow cellularity?

Answer 11

Is the composition and density of cells within the bone marrow

Question 12

These cells see an increase in numbers with age, within the bone marrow. The average adult marrow cellularity (% haemopoiesis)
is 40 - 60 %

Answer 12

Adipocytes

Question 13

Why are there fat spaces in the marrow?

Answer 13

-Those fats are stored in the form of triglyceride within the marrow. They serve as energy reserves in periods of increased energy demand, or decreased food intake
- Bone health: Play a role in bone remodelling and metabolism.

Question 14

How do we diagnose disease in the bone marrow?

Answer 14

• Bone marow biopsy

Question 15

What is the best site for marrow biopsy?

Answer 15

• iliac crest

Question 16

What are the samples obtained for bone marrow biopsy?

Answer 16

• Bone marrow aspirate (liquid bone marrow obtained containing blood cells, using a needle)
• Bone marrow trephine (bone marrow tissue is obtained using a large needle- done to diagnose haematological disoders such as leukemias, lymphomas, myeloma)

Question 17

What are the uses of the aspirate?

Answer 17

• Provide cells for cytological examination – cells spread
  on a slide, stained and examined microscopically. enables “morphological” study of cells
• Provide anticoagulated specimens for: flow cytometry
  cytogenetics, culture – TB, bacterial, fungal
• Provide uncoagulated specimen for DNA PCR and FISH

Question 18

What are the uses of trephine biopsy?

Answer 18

Used to see the:
- ARCHITECTURE of the bone marrow rather than individual cells
- granulomas
- infiltrating neoplasms e.g.
lymphoma, carcinoma
- marrow necrosis
- fibrosis

Question 19

What is trephine imprint or touch Prep?

Answer 19

A techniques that involves pressing the cut surface of the bone marrow core into a slide (can capture cellular material even if there is no fluid obtained through aspiration)

The technique is used in the case of dry tap; when the needle does not yield an adequate sample of the bone marrow fluid.

Question 20

Why go for trephine imprint?

Answer 20

• It can be done routinely.
• Very helpful if the marrow is infiltrated with tumour
• Helpful in cases of dry tap