Blood cell abnormalities

Question 1

What is anaemia?

Answer 1

A reduced amount of haemoglobin in a given amount of blood fro a person of that age and gender

Question 2

How can a healthy person get anaemia periodically?

Answer 2

By increasing their plasma volume as it would reduce their Hb concentration, however the excess fluid would be excreted

Question 3

What is the mechanism and cause of anaemia?

Answer 3

Mechanism - could be reduced synthesis of haemoglobin in the bone marrow
Cause - Condition causing reduced synthesis of haem or reduced synthesis of globin

Question 4

What can cause microcytic anaemia?

Answer 4

A defect in haem synthesis:
- Iron deficiency
Defect in globin synthesis (thalassaemia):
- Defect in alpha chain synthesis
- Defect in beta chain synthesis

Question 5

What can cause an iron deficiency?

Answer 5

• Increased blood loss
• Insufficient iron intake
• Increased iron requirement (e.g. pregnancy)

Question 6

What can cause macrocytic anaemia?

Answer 6

• Abnormal haemopoiesis:
  Red cell precursors continue to synthesise haemoglobin but don’t divide normally
• Megaloblastic erythropoiesis:
  The nucleus is delayed in maturation but the cytoplasm continues to grow and mature, so when the nucleus is mature, the cell is larger

Question 7

What is a megaloblast?

Answer 7

An abnormal bone marrow erythroblast

Question 8

A deficiency in which compounds results in megaloblastic anaemia?

Answer 8

B12 or folate

Question 9

What is polycythaemia?

Answer 9

Too many red cells in circulation:

- The Hb, RBC and Hct are all increased compared to a normal person of that age and gender

Question 10

What can cause polycythaemia?

Answer 10

Excessve transfusion, response to hypoxia, inappropriate erythropoietin use, abnormal function of the bone marrow

Question 11

What is leukaemia?

Answer 11

Cancer of the blood, but is a bone marrow disease and not all patients have abnormal cells in the blood

Question 12

What are benign and malignant leukaemias called?

Answer 12

chronic(benign) and acute(malignant)

Question 13

What types of leukaemia are there?

Answer 13

It can be acute or chronic and, depending on the cell type, it can be lymphoid or myeloid

Question 14

Why do people get leuakemia?

Answer 14

It results from a series of mutations in a single stem cell
Can be be from unidentified oncogenic factors
Random errors can also accumulate in a person’s life
Tumour suppressor genes can also be lossed
The cell may not be able to repair DNA so an error persists in the cell

Question 15

What can cause luekaemogenic mutations?

Answer 15

• Irradiation
• Anti-cancer drugs
• Cigarette smoking
• Chemicals(e.g. benzene)

Question 16

What is the difference between acute and chronic leukaemia?

Answer 16

Acute causes a failure of production of normal functioning end cells whereas chronic results in an increased number of end cells produced
In acute, usually transcription factors are mutated so multiple genes are affected whilst in chronic, a mutation occurs affecting a gene encoding a protein in the signalling pathway between the cell surface receptor and the nucleus

Question 17

How does leukaemia lead to diseases characteristics?

Answer 17

Accumulation of abnormal cells leads to: Leucocytosis, bone pain(if acute), hepatomegaly, splenomegaly, lymphadenopathy(if lymphoid), thymic enlargement(if T lymphoid)
Lack of normal cells leads to: Anaemia, leucopenia, thrombocytopenia