Red Blood Cells

Question 1

What do all blood cells originate from?

Answer 1

Haematopoetic stem cells

Question 2

Where does foetal haematopoeisis start?

Answer 2

The yolk sac

Question 3

Which bones in children does haematopoiesis occur in?

Answer 3

All bones

Question 4

Which bones in adults does haematopoiesis occur in?

Answer 4

Long bones - femur, pelvis, sternum

Question 5

What are the two characteristics of HSC?

Answer 5

The can self renew and they can differentiate

Question 6

What are the two cells that HSC differentiate into?

Answer 6

Common Lymphoid Progenitor and Common Myeloid Progenitor

Question 7

What is the intravascular life span of red blood cells?

Answer 7

120 days

Question 8

Where does erythropoiesis occur?

Answer 8

Bone Marrow

Question 9

What is HAEM iron also known as?

Answer 9

Ferrous iron - fe2+

Question 10

What is non-HAEM iron also known as?

Answer 10

Ferric iron - fe3+

Question 11

What affect do phytates have on iron absorption?

Answer 11

They reduce it

Question 12

What organs is excess iron toxic to?

Answer 12

Heart and liver

Question 13

Where is ferroportin found?

Answer 13

In duodenum enterocytes

Question 14

How do we lose iron if it is high?

Answer 14

Higher iron leads to HEPCIDIN release, which blocks ferroportin, so iron cannot leave the enterocytes. Therefore when the enterocyte is destroyed so is the iron stored within it

Question 15

What does inflammation do to Hepcidin?

Answer 15

Increases hepcidin, and therefore can lead to anaemia of inflammation as there is not enough iron in the blood as it is all being kept within the enterocytes

Question 16

Why do we need Folate and Vitamin B12?

Answer 16

They are needed for dTTP synthesis - thymidine, needed for DNA synthesis

Question 17

What can a Vitamin B12 and Folate deficiency cause?

Answer 17

Megaloblastic erythropoiesis - this is because the cells keep dividing but lack the DNA

Question 18

Name three sources of Folate

Answer 18

Green leafy vegetables, cauliflower and Brussels sprouts

Question 19

Name three sources of B12

Answer 19

Meat, fish, clams

Question 20

What does B12 combine with so it can be absorbed?

Answer 20

Intrinsic factor which is made in the gastric parietal cells

Question 21

What causes vitamin B12 deficiency

Answer 21

Inadequate intake, pernicious anaemia and malabsorption

Question 22

What is pernicious anaemia?

Answer 22

This is where your body does not make IF therefore the B12 cannot bind and therefore cannot be absorbed

Question 23

Why do red blood cells have a life span of 120 days?

Answer 23

When they move through capillaries and blood vessels, the walls bend and stretch meaning they get damaged

Question 24

Where are the red blood cells destroyed?

Answer 24

Spleen

Question 25

What are the RBCs broken down into?

Answer 25

HAEM and globin

Question 26

What does the HAEM part of the RBC after it is destroyed?

Answer 26

Gets broken down into bilirubin

Question 27

How is bilirubin excreted

Answer 27

In bile

Question 28

Why is bile important

Answer 28

Contains bile salts which are needed for the emulsification of fats so they can be absorbed

Question 29

What are the three types of granulocytes

Answer 29

Neutrophil, basophils and eosinophil

Question 30

What does hypochromia mean?

Answer 30

Too little haemoglobin so pale

Question 31

What is a polychromatic RBC?

Answer 31

One that is too read due to too much haemoglobin What is the only substrate that the brain can use as a source of energy?

Question 32

What are target cells?

Answer 32

When you have an accumulation of hemoglobin in the area of central pallor

Question 33

What causes the presence of target cells?

Answer 33

Jaundice, liver disease, hyposplenism

Question 34

What does anisocytosis mean

Answer 34

Variation in size

Question 35

What does poikilocytosis mean

Answer 35

Variation in shape

Question 36

What causes sickle cells?

Answer 36

Due to the polymerisation of HbS which forms tachtoids that distort the shape of the RBC

Question 37

What is the mutation that causes sickle cell disease? SICKLE CELL SIX GIVES ME A CRISIS

Answer 37

Charged glutamic acid residue at positive 6 in beta Hb gene is replaced by uncharged valine

Question 38

“Normal” Hb is determined by many things like..

Answer 38

Gender and physiological status eg altitude

Question 39

What type of distribution fo Hb concentrations show?

Answer 39

Gaussian distribution

Question 40

An infant with sickle cell anaemia (HbSS) develops symptoms of fatigue and pain. Blood tests reveal anaemia with thrombocytopenia. Examination reveals a mass on the left-hand side of his abdomen. Given this information, what could be the most likely explanation for his symptoms?

Answer 40

Pooling of blood in the spleen - spleenic sequestration

Question 41

What is Crohn's Disease?

Answer 41

inflammatory bowel disease which often involves ulcer formation in the mucosal layer of the intestines.

Question 42

How can Crohn's disease lead to iron-deficiency anaemia?

Answer 42

Crohn's disease can lead ulcer formation in the stomach, meaning internal bleeding can occur. This may result in iron-deficiency anaemia due to blood loss

Question 43

What regulates the proliferation and differentiation of Haematopoietic stem cells?

Answer 43

Haematopoietic growth factors

Question 44

A 28-year old female has some tests carried out following a full blood count that subsequently reveal that she is folate deficient. What changes in the red blood cells would you expect to see.

Answer 44

Macrocytic cells

Question 45

Which cells do myeloid stem cells give rise to?

Answer 45

Red blood cells, granulocytes, monocytes, mast cells and basophils

Question 46

What is the life span and function of a platelet?

Answer 46

10 Days - Haemostasis

Question 47

What is the life span and function of a monocyte?

Answer 47

Several days, defense against infection by phagocytosis

Question 48

What is the life span and function of a neutrophil?

Answer 48

7-10 hours - defense against infection by phagocytosis and killing of micro-organisms

Question 49

At what point does the liver take over haematopoiesis in the foetus?

Answer 49

6-8 weeks gestation

Question 50

What are haematopoietic growth factors?

Answer 50

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

Question 51

What is the haematopoietic growth factor which influences red cell production?

Answer 51

Erythropoietin

Question 52

What are the haematopoietic growth factors which influence granulocyte and monocyte production?

Answer 52

G-CSF, G-M CSF, cytokines e.g. interleukins

Question 53

Which common progenitor do megakaryocytes derive from?

Answer 53

Myeloid

Question 54

What are three causes of microcytic anaemia?

Answer 54

Iron deficiency Pregnancy Childhood

Question 55

What are three causes of macrocytic anaemia?

Answer 55

(B12/folate deficiency)- alcohol excess, pregnancy, vegan diet

Question 56

What are the two main functions of iron?

Answer 56

Oxygen transport in haemoglobin Mitochondrial proteins cytochromes a, b and c: for production of ATP

Question 57

Why is ferric iron not as easily absorbed?

Answer 57

and requires action of reducing substances (e.g. vitamin C) for absorption

Question 58

How does anaemia of chronic disease/inflammation occur?

Answer 58

Pro-inflammatory cytokines such as IL-1, TNF-alpha, IL-6 and IFN-gamma work to decrease EPO production, and increase hepcidin - increased hepcidin means less iron absoprtion in the gut as hepcidin binds to ferroportin, meaning iron is unable to leave theenterocytes and therefore is destroyed when the entoercytes die

Question 59

When is hepcidin released?

Answer 59

Released from the liver in response to high storage iron

Question 60

What can cause a deficiency in B12?

Answer 60

inadequate intake e.g. veganism - inadequate secretion of IF: pernicious anaemia (an autoimmune disorder) Malabsorption e.g. coeliac disease lack of acid in stomach (achlorhydria)

Question 61

During what situations do the requirements for folic acid increase?

Answer 61

During pregnancy and during red cell production

Question 62

What three things does erythrocyte function depend on?

Answer 62

Integrity of the membrane Haemoglobin structure and function Cellular metabolism

Question 63

What structures help t maintain the integrity and shape of the red cell?

Answer 63

The red cell membrane - made of lipid bilayers which is supported by proteins and contains transmembrane proteins

Question 64

What are the transmembrane proteins found in red cell membrane?

Answer 64

Band 3 and rhesus

Question 65

What are the skeletal proteins found in red blood cells membrane?

Answer 65

Spectrin and junctional

Question 66

What does a disruption to vertical linkages in the red blood cell membrane cause?

Answer 66

Hereditary Spherocytosis

Question 67

What would be seen on a blood film of a patient with hereditary spherocytosis?

Answer 67

Rounded, with a regular outline and lacking central pallor

Question 68

Disruption of horizontal | linkages in red cell membrane produces...

Answer 68

Hereditary elliptocytosis

Question 69

How does deficiency in G6PD affect red cells?

Answer 69

1. G6PD is an important enzyme in the HMP shunt 2. The HMP shunt is involved in metabolism of glutathione which protects the red cell from oxidant damage 3. Therefore deficiency of G6PD causes red cells to be vulnerable to oxidant damage

Question 70

What protects the red cells from oxidant damage?

Answer 70

Glutathione

Question 71

What does G6PD deficiency cause?

Answer 71

G6PD deficiency usually causes intermittent, severe intravascular haemolysis as a result of infection or exposure to an exogenous oxidant

Question 72

What are episodes of intravascular haemolysis associated with the appearance of?

Answer 72

considerable numbers of Irregularly contracted cells/ ‘bite cells’