Anaemia (general)

Question 1

Question 2

In adults, the predominant site of haematopoiesis is the []

Here we find the multipotent [] stem cells (HSCs).

Answer 2

In adults, the predominant site of haematopoiesis is the bone marrow.

Here we find the multipotent hematopoietic stem cells (HSCs).

Question 3

Multipotent hematopoietic stem cells (HSCs) can differentiate into which cell lineages? [2]

Answer 3

Myeloid or lymphoid cell lines

Question 4

Describe the lineage of multipotent lymphoid stem cells [4]

Answer 4

Lymphoid progenitor:

• B-lymphocyte –> plasma cell
• T-lymphocyte
• NK cell

Question 5

Describe the lineage of multipotent myeloid stem cells [4]

Answer 5

Question 7

What is TPO? [1]
Where is it produced? [1]
What does it regulate ? [1]

Answer 7

Thrombopoietin (TPO):
TPO is produced by the liver and essential for the control of platelet production

Question 8

Platelets are derived from which cell type? [1]

Answer 8

Platelets are derived from megakaryocytes within the bone marrow.

Question 9

Define pancytopenia [1]

Answer 9

The presence of anaemia, leucopenia and thrombocytopenia together

Question 10

Where does each stage of haematopoiesis occur in fetus life?

Answer 10

1. yolk sac (3 weeks)
2. liver (6 weeks)
3. spleen (8 weeks)
4. bone marrow

You Love a Smart Bunny

Question 11

What is the role of erythropoietin in erythropoiesis? [2]

Answer 11

EPO stimulates bone marrow erythropoiesis:

1. produces production of proerythroblasts
2. speeds up maturation of erythroblasts

Question 12

Where is EPO produced? [1]

Answer 12

The kidneys

Question 13

What condition causes the stimulation of EPO production? [1]

Answer 13

EPO production is activated by hypoxia and is regulated via an oxygen-sensitive feedback loop

Question 14

What is the pathway from Haematopoietic stem cell (HPSCs) - to erythrocyte? [1]

Answer 14

Haematopoietic stem cell (HPSCs)
–>
common myeloid progenitor cell (CMPC)
–>
Proerythroblast
–>
erythroblast
–>
reticulocyte
–>
erythrocyte

The proerythroblast develops into an (early) erythroblast. The erythroblast then undergoes a sequence of changes where its nucleus progressively shrinks and its cytoplasm becomes filled with haemoglobin (not stained). When full of haemoglobin it is called a normoblast. The normoblast then expels its nucleus and becomes a reticulocyte. Most reticulocytes stay in the marrow and mature into erythrocytes but some may be released into the blood, especially after haemorrhage. Reticulocytes can transport oxygen, just not as efficiently as mature erythrocytes. They can mature into adult RBCs in the circulation

Question 15

Which type of transporters do rbc use to obtain glucose?

GLUT1
GLUT2
GLUT3
GLUT4
GLUT5

Answer 15

Which type of transporters do rbc use to obtain glucose?

GLUT1
GLUT2
GLUT3
GLUT4
GLUT5

Question 16

Describe how erythrocytes undergo energy metabolism [1]

Answer 16

RBCs have no mitochondria – so can’t use oxidative metabolism to make ATP.

They need ATP to power cell membrane sodium pumps – otherwise cells would swell up and burst.

Make ATP via Anaerobic Glycolysis from glucose : 2 ATP produced

Lactate is pumped out of erythrocyte into plasma, taken up by liver or muscle cells (especially myocardium), and converted back to glucose - similar mechanism to CORI CYCLE in muscle.

Question 17

Describe the process of haem. degredation

Answer 17

(Iron has already been recycled)

1. Haem turns into unconjugated bilirubin
2. Liver takes up unconjugated bilirubin, and via bilirubin diglucoronide is conjugated with glucoronic acid
3. sent to gall bladder and stored in bile
4. biled secreted and goes to gut
5. bilirubin converted to urobilinogen and then oxidised to stercobilin & excreted in faeces. some urobilinogen is converted to urobilin and excreted in urine

Question 18

What are the causes of microcytic anaemia? [5]

Answer 18

T – Thalassaemia
A – Anaemia of chronic disease
I – Iron deficiency anaemia
L – Lead poisoning
S – Sideroblastic anaemia (disorder where the body produces enough iron but is unable to put it into the haemoglobin)

Question 19

Explain what elevated erythrocyte Sedimentation Rate test indicates [1]

Answer 19

Elevated sedimentation rate (ESR): indicates inflammation

• Erythrocytes have negative surface charge
• Ensures that they electrostatically repel each other and do not stick together, particularly in capillaries.
• Inflammatory cytokines or bacteria in blood increase amount of (positively charged) fibrinogen in plasma*
  *Excess fibrinogen binds to red cell membrane and reduces its negative charge, causing RBCs to adhere
• Therefore, rate of sedimentation increases as clumps of RBCs fall down through test tube more quickly.

Question 20

Include iron stuff.

Question 21

What is the treatment for normocytic anaemias? [1]

Answer 21

Treatment is with erythropoietin.

Question 22

Describe the different classifications of macrocytic anaemia [2]

Answer 22

Megaloblastic:
- B12 deficiency
- Folate deficiency

Normoblastic macrocytic:
* Alcohol
* Reticulocytosis (usually from haemolytic anaemia or blood loss)
* Hypothyroidism
* Liver disease
* Drugs, such as azathioprine

Question 23

Name 5 drugs which cause macrocytic anaemia?

Answer 23

Azathioprine
Methotrexate
Fluorouracil
Phenobarbital
Mercaptopurine
Trimethoprim