Red Blood cells and anaemia (1)

Question 1

What is the blood ?

Answer 1

• It is a liquid that is composed of the plasma and also the cells suspended inside the plasma

Question 2

What are the functions of the blood?

Answer 2

• Transport: O2, Nutrients, Co2 and waste products
• Immune response

Question 3

What is the % composition of plasma and cells in the blood?

Answer 3

• Plasma 55%
• Cells 40-45%

Question 4

What are the cell types found in the blood?

Answer 4

• Red cells (erythrocytes, RBC)
• White cells (leucocytes, WBC)
• Platelets (thrombocytes)

Question 5

What is Haemopoiesis ?

Answer 5

• Site of production of the blood cells

Question 6

State the different stages of Haemopoiesis

Answer 6

• Starts in yolk sac at 3rd week of gestation
• 6 wks- 6 mo: liver, spleen (extramedullary)
• 6 mo-birth: bone marrow taking over (medullary)
• In adult life: bone marrow
• Extramedullary haemopoiesis in disease

Question 7

What is the difference between extramedullary and medullary?

Answer 7

• bone marrow production is called medullary production
• If it is outside the bone marrow, it is called extramedullary production. If this happens after birth it is only seen in diseased conditions

Question 8

What do the general stages of blood cell differentiation

Answer 8

• Pluripotential stem cells -> Myeloid or Lymphoid stem cells -> Committed stem cells -> Earliest recognisable precursors -> Mature cells

Question 9

What is erythropoiesis

Answer 9

• The production of red blood cells

Question 10

State the stages of the Erythropoiesis process

Answer 10

• Stem cell -> proerythroblast -> Erythroblast (early, late) -> Normoblast (early, late) -> Reticulocyte -> erythrocyte
• The nucleus changes throughout these stages
• All in the bone marrow but erythrocytes in the peripheral blood

Question 11

What are the main features of Erythropoiesis?

Answer 11

• It is in several stages of mitosis and maturation, the mature cells are the reticulocytes
• Erythropoietin - Hormones secreted to increase RBC production
• Essential dietary constituents: Iron, Vit B12, Folic acid

Question 12

What is Anaemia?

Answer 12

• The haemoglobin concentration is lower than the reference value for age and gender
• Reduction in red cell mass

Question 13

What are the three major types of Anaemia

Answer 13

• Hypochromic microcytic with a low MCV
• Normochromic normocytic with a normal MCV
• Macrocytic with a high MCV

Question 14

How is Anaemia classified

Answer 14

• Classified in terms of the red cell indices (MCV)

Question 15

What is the pathological consequences of anaemia?

Answer 15

• Tissue hypoxia

Question 16

What are the clinical manifestations of Anaemia?

Answer 16

• Maybe asymptomatic
• Symptoms (non-specific): fatigue, headache, faintness
• Signs: pallor (e.g. conjunctiva)

Question 17

what Laboratory investigation indicates
Anaemia?

Answer 17

• Decrease in red blood cells, haemoglobin, packed cell volume
• Blood film: Anisocytosis (variation in size), Poikilocytosis (variation in shape), Anisochromasia (variation in haemoglobinisation)

Question 18

What are the causes of Anaemia?

Answer 18

• Decreased production: SUPPRESSED PROLIFERATION (bone marrow function is compromised), DEFECTIVE MATURATION (haematinic deficiency)
• Increased destruction/loss: HAEMORRHAGE (bleeding), HAEMOLYSIS (internal loss of RBC)

Question 19

What is Iron deficiency also known as? Explain what it means

Answer 19

• Also known as MICROCYTIC, HYPOCHROMIC ANAEMIA
• microcytic = reduced cell size
• hypochromic = reduced haemoglobin concentration

Question 20

What is the most common cause of anaemia?

Answer 20

• Fe deficiency

Question 21

What does Fe deficiency blood picture look like?

Answer 21

• Microcytic, hypochromic

Question 22

What happens in iron metabolism?

Answer 22

• Iron status largely controlled by absorption
• Absorption: Fe+++ -> Fe++; gastric HCL required
• stored as ferritin and haemosiderin
• carried by transferrin