Haemopoiesis

Question 1

What white cells modulate hypersensitivity rxns?

Answer 1

Eosinophils and Basophils

Question 2

Which cell destroys parasites?

Answer 2

eosinophils

Question 3

What are the diff. types of lymphocytes?

Answer 3

B-cells (Abs)
Tcells
NK cellls (anti-viral/ tumor)

Question 4

What do monocytes convert to in the tissues?

Answer 4

Macrophages

Question 5

What may be present in high no.s with acute inflammation?

Answer 5

Neutrophils

Question 6

What do macrophages do?

Answer 6

phagocytic clearance

Question 7

What is the lifespan of neutrophils?

Answer 7

7-10 days

1 mill. platelets are made/ sec

Question 8

What is a myelocyte?

Answer 8

nucleated precursor between neutrophils and blasts

Question 9

What do all “blast” cells have in common?

Answer 9

they are NUCLEATED (erythroblast/ myeloblast)

Question 10

Name the immediate red cell precursor.

Answer 10

Reticulocytes (polychromasia)

Question 11

Name the platelet precursor.

Answer 11

megakaryocytes (polypoid)

Question 12

Where do these progenitor/precursor cells come from?

Answer 12

HAEMOPOIETIC STEM CELLS

Question 13

What do the multipotent progenitor cells give rise to ?

Answer 13

Myeloid progenitor

Lymphoid progenitor

Question 14

What particular cell can self-renew?

Answer 14

stem cells

ft lost in following descendents

Question 15

What is seen with differentiation in haemopoiesis?

—–What may occur simultaneously with differentiation?

Answer 15

• stem cell descendants commit to ONE or MORE lineages

- proliferation (which may also occur simultaneously with maturation)

Question 16

What happens in maturation of descendant cell?

Answer 16

• descendants acquire FUNCTIONAL properties and may stop proliferating

Question 17

Where do haemopoietic stem cells originate embryonically?

Answer 17

• from the MESODERM

Question 18

Where is the first site of erythroid acitivity in an embryo?

Answer 18

YOLK SAC

stops by week 10

Question 19

What picks up on haemopoiesis, after the yolk sac and when?

Answer 19

• at week 6, LIVER starts

–by week 16, Bone marrow starts

Question 20

Where does haemopoiesis occur in the marrow?

Answer 20

• in AXIAL skeleton (best)
• PELVIS
• PROXIMAL LONG bones

Question 21

Haemopoiesis of the TIBIA and FEMUR drastically falls by what age?

Answer 21

tibia: by 20 y.o

femur: by 25 y.o
- —-so NOT the best place to obtain bone marrow sample retrieval

Question 22

Best place for bone marrow biopsy?

Answer 22

• iliac crest

- Sternum

Question 23

Where is bone marrow biopsy obtained from in a bby?

Answer 23

• anterior tibia

Question 24

What is seen under the microscope of a bone marrow sample?

Answer 24

1. cellular: Haemopoietic cells and Non hemopoietic cells
2. Connective tissue matrix
3. Vascular elements

Question 25

What are non-haemopoietic cells like?

Answer 25

- adipocytes - fibroblasts - osteoclasts/ osteoblasts

Question 26

Describe the relation between arteriole and venou sinsuses in the bone marrow vasculature.

Answer 26

- arterioles DRAIN into sinuses (wide venous vessels> open into LARGER central sinuses) - ---SINUSES are radially distributed around the draining CENTRAL sinus

Question 27

What is the diff. between vein and sinuses?

Answer 27

----sinuses are larger and have a DISCONTINUOUS BM

Question 28

How do formed blood cells make its way into the circulation?

Answer 28

-the blood cells pass through the fenestrations in the endothelial cells of the sinusoids

Question 29

WHat is the release of red cells associated with?

Answer 29

- sinusoidal dilatation and INCR. blood flow

Question 30

Why are there fewer choices for bone marrow sampling retrieval in older people?

Answer 30

(can't retrieve from proximal long bones at old age) ---d.t INCR. in YELLOW marrow (Fatty, inactive marrow) with AGE vs LOSS of red (haemopoietically active) marrow.

Question 31

What is the myeloid: erythroid ratio?

Answer 31

- ratio of myeloid to erythroid PRECURSORS to the bone marrow (1. 5:1)--> (3.3:1)

Question 32

When may myeloid : erythroid ratio reverse?

Answer 32

in hemolysis | - as a compensatory response

Question 33

What regulates haemopoiesis?

Answer 33

1. Intrinsic propert. of cells 2. Signals from immediate surroundings and the periphery (MICROENV. factor) 3. specific anatomical area (NICHE) for optimal developmental signals

Question 34

What regulates neutrophil precursor maturation?

Answer 34

G-CSF | granulocyte - colony stimulating factor

Question 35

WHat regulates the growth and development of megakaryocytes from their precursors?

Answer 35

Thrombopoietin

Question 36

What microenvironmental regulation exists for haemopoiesis?

Answer 36

- haem-poietic stem cells OCCUPY a NICHE (anatomical site) ----that provides signals for expansion/ differentiation or dormancy - ---site: around arteriole/ sinusoid; provides access to diff. signals (cytokines) ----site is ALTERED in disease/ therapy

Question 37

How to assess haemopoiesis?

Answer 37

1. Blood count/ cell indices/ morphology | 2. Less common: BONE marrow examination----usually to see precursor cell acitivity

Question 38

What test are sufficient for NON-lymphoid cells?

Answer 38

- bloood count | - morphological assessment

Question 39

How to assess lymphoid cells?

Answer 39

- the expression of antigens (indicate lineage/ stage development) by immunophenotyping

Question 40

What does immunophenotyping curtail?

Answer 40

- way to IDENTIFY patterns of protein expression UNIQUE to a celll lineage - ---Ag expression study done with specific Abs =

Question 41

How do you recognize diff. lymphocyte subsets?

Answer 41

- monoclonal Abs SPECIFIC for each marker (anti- CD45/ CD3/CD4 Etc) - -which are covalently labelled with fluorrescent dyes ----each Ab will cause cells that it recognises to FLUORESCE with a unique color

Question 42

How do you quantify the fluorescent findings of lymphocyte sybsets?

Answer 42

- ----pt sample that is stained with fluorescent monoclonal Abs in the Trucount tube (containing the Trucount beads) - is then run through the Flow cyotmeter together with the Trucount beads --allowing calculation of the absolute Value of cell no. for each subset