Red Blood Cells

Question 1

Which part of the body do blood cells originate from?

Answer 1

Bone marrow

Question 2

What are blood cells derived from?

Answer 2

Pluripotent haematopoietic stem cells (HSCs)

Question 3

Pluripotent haematopoietic stem cells (HSCs)

Answer 3

Self renew
Differentiate to mature progeny

Question 4

Sites of haematopoiesis

Answer 4

Yolk sac generation of HSC
Liver HSC maintenance and expansions
Bone marrow mainly pelivis femur and sternum

Question 5

What regulates haematopoiesis

Answer 5

Genes transcription factors growth factors and micro environment

Question 6

What occurs if regulation disrupted

Answer 6

Can lead to leukaemia or bone marrow failure

Question 7

Haematopoietic growth factors:

Answer 7

• Glycoprotein hormones which bind to cell surface receptors
• Regulate proliferation and differentiation of HSCs
• Regulate function of mature blood cells

Question 8

Erythropoietin

Answer 8

Regulated erythropoiesis

Glycoprotein cytokine that regulates erythropoiesis

Made in the kidney in response to hypoxia

It interacts with erythropoietin receptors on red cell progenitor membranes → stimulates bone marrow to increase RBC production

Question 9

Erythropoiesis

Answer 9

Development of red blood cells

Question 10

What 4 things are required for erythropoiesis

Answer 10

Iron
B12
Folate
Erythropoietin

Question 11

When is erythropoietin (EPO) synthesized

Answer 11

Synthesized in response to hypoxia

Question 12

Iron

Answer 12

Transports oxygen and absorbed in duodenum
Fe2+ best absorbed Fe3+ requires vit c

Question 13

Hepcidin

Answer 13

Controls absorption of iron so only 1-2mg absorbed. It binds to ferroportin is the duodenum preventing iron absorption

Question 14

What does B12 bind to

Answer 14

Combines with intrinsic factor making B12-IF
In small intestine it binds to receptors in ileum

Question 15

Where is Folic acid absorbed

Answer 15

Absorbed in small intestine

Question 16

B12 deficiency caused by

Answer 16

Inadequate intake
Malabsorption due to coeliac disease
Lack of stomach acid

Question 17

Where are erythrocytes destroyed

Answer 17

In spleen

Question 18

Erythrocyte life span

Answer 18

120 days

Question 19

Erythrocyte shape

Answer 19

Made of lipid bilayer supported by protein cytoskeleton
Spherocytosis when vertical linkages are disrupted
Elliptocytosis is disruption to horizontal linkages occurring in iron deficiency

Question 20

What gives rise to a proerythroblast

Answer 20

Common myeloid progenitor-proerythroblast-erythrocyte

Question 21

What deficiency gives microcytic anaemia

Answer 21

Iron deficiency

Question 22

What gives macrocytic anaemia

Answer 22

B12 or folate deficiency
Use of drugs interfering with dna synthesis
Liver disease and ethanol toxicity
Haemolytic anaemia

Question 23

Reduction of B12 and folate

Answer 23

Causes dttp deficiency so thymidine can’t be made so dna can’t replicate affecting cells in bone marrow which can’t divide , epithelial surfaces and in mouth and gut

Question 24

Anaemia

Answer 24

Is the reduction in the amount of haemoglobin present in a given volume of blood

Question 25

Haemolysis

Answer 25

Rbc become less flexible so are removed prematurely by spleen

Question 26

Anemia of chronic disease

Answer 26

Caused by autoimmune disease malignancy inflammatory conditions kidney disease and infections. Iron supplements won’t help patients

Question 27

Glucose 6 phosphate dehydrogenase deficiency

Answer 27

X linked disorder Is a haemolytic anemia which results from cells inability to make glutathione.increases susceptibility to oxidative damage and cell death. Heinz bodies are markers for oxidative damage.

Question 28

Intravascular haemolysus

Answer 28

Causes bite cells

Question 29

What is the most abundant cytoskeletol protein

Answer 29

Spectrin

Question 30

Increased hepcidin means

Answer 30

Less iron absorption less iron transport and less iron available to red blood cells

Question 31

Howell jolly bodies

Answer 31

Erythrocytes which fail to expel a fragment if dna during maturation seen as a blue dot in the cell. Can be indicative of spleen malfunction so related to sickle cell anaemia and megaloblastic anaemia

Question 32

What is anaemia

Answer 32

Reduction in the amount of haemoglobin in a given volume of blood. Due to rbc failure of production or destruction

Question 33

Hypochromia

Answer 33

Cells have a larger central pallor so less haemoglobin and flatter cell(usually looks like it has a hole)

Question 34

Causes of microcytic anaemia

Answer 34

Iron deficiency Anaemia of chronic disease

Question 35

Thalassaemia (Globin synthesis defect)

Answer 35

Defect in B chain or a chain synthesis

Question 36

Reduced ferritin

Answer 36

Reduces hepcidin production Increased iron supply

Question 37

Polychromasia

Answer 37

Blue tinge in cell cytoplasm Indicates red cell is young Cells are larger than normal rbc

Question 38

Target cells

Answer 38

Red cells with accumulation of haemoglobin Occur due to obstructive jaundiced Liver disease Haemoglobinopathies Hyposplenism Look like donuts

Question 39

Sickle cell anaemia

Answer 39

Caused by mutation in b globin gene Causes sickle shaped rbc Carriers of one gene have the sickle trait but are asymptomatic

Question 40

Megaloblast

Answer 40

Abnormal erythroblast which is larger than normal caused by vitamin B12 deficiency or folate and is a cause if macrocytic anaemia

Question 41

What 3 mechanisms results in anaemia

Answer 41

Reduced production of red cells by bone marrow eg iron deficiency B12 or folate or leukamia Loss of blood eg gastrointestinal bleeding Reduced survival of red cells eg sickle cell disease G6PD deficiency and sperocytosis

Question 42

Why do patients with sickle cell not feel fatigued

Answer 42

As there is decreased affinity of HbS binding to oxygen

Question 43

What is 2,3 DPG

Answer 43

Modulates oxygen affinity by binding to haemoglobin Increasing 2,3 DPG means oxygen is released from haemoglobin

Question 44

- Megakaryocytopoiesis and platelet production growth factor?

Answer 44

Thrombopoietin

Question 45

Heteroplasmy

Answer 45

In thalasemmia the more chains that are affected the more sever the symptoms out of the 4 Globin chains

Question 46

Polycythemia

Answer 46

Too many red blood cells Due to over transfusion,hypoxia,inappropriate erythropoietin use Leads to thickening of blood