Haematology Lecture 2

Question 1

What is haemtopoiesis

Answer 1

Production of blood cells

Question 2

Where do all cells originate from

Answer 2

Stem cells in the bone marrow (haematopoietic stem cells)

Question 3

What is the formation of red blood cells called

Answer 3

Erythropoiesis

Question 4

What is formation of platelets called

Answer 4

thrombopoiesis

Question 5

What is the formation of granulocytes and monocytes called

Answer 5

Myelopoeis

Question 6

What type of cell can differentiate into any blood cell

Answer 6

-Multi potential hematopoietic stem stell(hemocytoblast)
-divides into either common myeloid progenitor or common lymphoid progenitor which then divide further

Question 7

How is a erythrocyte formed

Answer 7

-made my the process called erythropoietin’s which occurs in the bone marrow
Sequence:
-haematopoetic stem cell
-multipotent progenitor cell
-myeloid progenitor cell
-proerythrocytes (Normoblast)
This occurs in blood marrow
-reticulocyte (An immature red blood cell)
-erythrocyte
This occurs in the blood stream

Question 8

What happens when a cell which is Going to be an erythrocyte is at the proerythroblast stage (normoblast)

Answer 8

As it starts to become a erythrocytes it gets smaller,the amount of haemoglobin increases,it loses rna and protein synthesis apparatus as it no longer has a nucleus

Question 9

Where are normoblasts found

Answer 9

Bone marrow

Question 10

What regulates erythropoiesis

Answer 10

Balance between red blood production and destruction which depends on hormonal controls as well as a adequate supplies of iron,amino acids, and b vitamins

Question 11

What does too few red blood cells cause

Answer 11

Tissue hypoxia which is detected by type kidney

Question 12

What does too many red blood cells cause

Answer 12

It increases blood viscosity which can cause The formation of blood cloths

Question 13

What is hormone erythropoietin(EPO)

Answer 13

• a small 30.4 kD glycoprotein hormone which acts on the early progenitor cells
  -it is a direct stimulus for erythopoiesis
  -there is always a small amount in blood to maintain basal rate
  -kidneys are the primary source however some from the liver

Question 14

What are effects of epo

Answer 14

➢Rapid maturation of committed marrow cells ➢Increased circulating reticulocyte count in 1–2 days

Question 15

What are consequences of abusing epo

Answer 15

Can be trapped In smaller vessels causing cloths

Question 16

Relationship between epo and testosterone

Answer 16

➢Testosterone enhances EPO production, resulting in higher RBC counts in males

Question 17

What stimulates epo to be produced

Answer 17

Low O2 levels (hypoxia) in blood stimulate kidneys to produce erythropoietin

Question 18

Causes of hypoxia

Answer 18

-Decreased RBC numbers due to haemorrhage or increased destruction
- Insufficient haemoglobin per RBC (e.g., iron deficiency)
- Reduced availability of O2 (e.g., high altitudes)

Question 19

Formation of erythrocytes due to epo sequence

Answer 19

1. Low O2 levels in blood stimulate kidneys to produce erythropoietin.
2. Erythropoietin levels rise in blood.
3. Erythropoietin and necessary raw materials in blood promote erythropoiesis in red bone marrow.
4. New erythrocytes enter bloodstream; function about 120 days.

Question 20

DIETARY REQUIREMENTS FOR ERYTHROPOIESIS

Answer 20

-nutrients such as amino acids,lipids,carbohydrates
-iron
>free ions are toxic it must be bound to other molecules
>stored in cells as ferritin and haemosiderin
>transported in blood where bounds to protein called transferrin
>vitamin b12(cobalamin) and folic acid necessary for dna synthesis for rapidly dividing cells (developing red blood cells)

Question 21

What is the protein called that transfers iron around the body

Answer 21

Transferrin which is synthesized in the liver and secreted into the plasma

Question 22

Daily iron cycle

Answer 22

-Daily loss and absorption of 1mg
-most of the iron in the body is contained in haemoglobin

Question 23

Destruction of erythrocytes

Answer 23

-life span of 100-120 days
-old red blood cells become fragile and haemoglobin begins to degenerate
-it it recycled in the spleen

Question 24

Causes of anaemia

Answer 24

➢Blood loss
➢Low RBC production ➢High RBC destruction

Question 25

Signs/symptoms of anemia

Answer 25

fatigue, pallor, shortness of breath, and chills,slower metabolism as blood 02 levels cannot support normal metabolism

Question 26

Haemorrhagic anaemia

Answer 26

-Haemorrhagic anaemia resulting from excessive blood loss
-two types
>acute which is blood loss around eg stab wound which can be treated by blood replacement
>chronic which is slight but persistent blood loss eg bleeding ulcer or haemorrhoids it can be treated by treating the primary problem

Question 27

Causes of anaemia

Answer 27

-iron deficiency
-pernicious which is rare but its when the GI tract can’t absorb b 12 ,it is autoimmune can Can be treated by b12 injections
-renal anaemia which is when the kidneys cannot produce epo, it can be treated by epo injections

Question 28

Normal haemoglobin values

Answer 28

Males:130-180g/l
Females:120-160g/l

Question 29

What is the most common cause of iron deficiency

Answer 29

-Iron deficiency
-Prevalence of 2–5% among adult men and post-menopausal women in the
developed world
-Caused by haemorrhagic anaemia, low iron intake, or impaired absorption
-RBCs are small (microcytic) and pale (hypochromic)
-Iron supplements to treat

Question 30

What is haemolytic anaemia

Answer 30

-premature red blood cell lysis
-done by the spleen
-caused by
>Incompatible transfusion
>Infections
>Haemoglobin abnormalities
>sickle cell anaemia

Question 31

Sickle cell anaemia

Answer 31

Normal erythrocyte has normal haemoglobin amino acid sequence in the beta chain

Sickled erythrocyte results from a single amino acid change in the beta chain of haemoglobin.

Val instead of glu