Red Blood Cells (RBC)

Question 1

How much Blood Volume a normal 70kg adult contain?

Answer 1

5L, of which 40% cells and 60% plasma

Question 2

Describe anaemia and polycythaemia

Answer 2

Anaemia is having a lower percentage of blood cells compared to normal. Polycythaemia is having a higher percentage of blood cells compared to normal.

Question 3

What is the life span of RBC?

Answer 3

100 days

Question 4

Why are RBC subject to high pressures?

Answer 4

Because they are squeezed through narrow capillaries every minute

Question 5

Describe the appearance of a RBC?

Answer 5

Has a biconcave disc appearance and no nucleus

Question 6

What makes RBC flexible?

Answer 6

Because they have no nucleus, thus increase surface area

Question 7

What maintains the gas exchange in RBC? and what makes that gas exchange fast?

Answer 7

Gas exchange is faster because of the high surface area of a RBC, and it is maintained by a complex cytoskeletal system

Question 8

Why RBC are unable to divide?

Answer 8

Because they have no nucleus or ribosomes

Question 9

What is the main function of RBC?

Answer 9

Transport oxygen and carbon dioxide, and maintain acid and base balance. This is by maintaining membrane integrity and preventing oxidation of haemoglobin

Question 10

Where does haemopoiesis occur?

Answer 10

In bone marrow.

Question 11

What is extramedullary haemopoiesis?

Answer 11

A haemotological disease that occurs when haemopoiesis occurs in the spleen or liver

Question 12

What does bone marrow stroma contain?

Answer 12

Macrophages, endothelial cells, fibroblasts, fat cells and associated stromal proteins

Question 13

What is used to stain macrophages in marrow?

Answer 13

Peroxidase - stains brown

Question 14

What are the growth factors that drive maturation?

Answer 14

Interleukin 3 
Erythropoitetin (biggest factor)
Androgens
Thyroxine 
Growth hormone

Question 15

Define reticulocytes

Answer 15

an immature red blood cells without a nucleus

Question 16

Define reticulin

Answer 16

Remnants of mRNA left once the nucleus of maturing RBC has been extruded (often removed by spleen in 1-2 days)

Question 17

Why is reticulin useful?

Answer 17

It is a useful measure of marrow response to anaemia or treatment

Question 18

How is reticulin stained?

Answer 18

By new methylene blue on slide, or an automated count

Question 19

What is the normal level of Iron in an adult?

Answer 19

3000-5000mg

Question 20

How much Iron does a daily diet contain? How much is actually absorbed, and in which form?

Answer 20

10-20mg. Only 1-2mg is absorbed in ferrous form

Question 21

In what cases more absorption of Iron is necessary?

Answer 21

Blood loss or pregnancy

Question 22

Where is the ferrous form of Iron transported to?

Answer 22

Duodenal enterocytes

Question 23

What is the regulator of Iron absorption and the release from macrophages?

Answer 23

Hepcidin (in gut)

Question 24

What are the mechanisms to excrete Iron?

Answer 24

There are no mechanisms

Question 25

What causes Iron loss?

Answer 25

``` Blood sampling Minor trauma Menstrual loss (period) Very small amounts in urine/skin shedding GI (1mL per day) ```

Question 26

How is Iron transported

Answer 26

Transferrin and Ferritin

Question 27

When are Transferrin receptors increased?

Answer 27

During Iron deficiency

Question 28

What is the best measure of Iron stores?

Answer 28

Ferritin

Question 29

What is the daily requirement of Folate and how much does a diet contain?

Answer 29

0. 1mg | 0. 25mg

Question 30

What contains folic acid and where is it absorbed?

Answer 30

Green vegetables and fruits It is absorbed in the upper small intestine/bowel

Question 31

What can cause deficiency in folic acid?

Answer 31

Poor intake, poor absorption and increased need

Question 32

What is the daily requirement of Cobalamin and how much does a diet contain?

Answer 32

1mg 5mg

Question 33

What contains B12 and where is it absorbed?

Answer 33

In animal derived products Absorbed in terminal ileum

Question 34

How is B12 moved into the terminal ileum?

Answer 34

Gastric parietal cells produce intrinsic factor that binds to B12 and stays in gut and moves into terminal ileum. Transported on transcobalamin II via protal circualtion liver

Question 35

What can cause deficiency in B12?

Answer 35

Vegan diet or perinicous anaemia

Question 36

What can cause gastric atrophy?

Answer 36

Antibodies to intrinsic factors

Question 37

What catalyses the conversion of uridine to thymidine?

Answer 37

The change from 5 THF to THF and then into 5,10 methelene THF, which is all started by B12

Question 38

What is the role of Erythropoietin?

Answer 38

It controls the rate of RBC production in blood marrow

Question 39

What produces Erythropoietin?

Answer 39

The kidney (90%) and the liver (10%)

Question 40

How is Erythropoietin regulated?

Answer 40

The body has no stores of Erythropoietin, and its regulation is at the gene transcription level

Question 41

How is Erythropoietin switched on?

Answer 41

Tissue hypoxia or anaemia High altitude Epo producing tumours (e.g. Kidney)

Question 42

What is Erythropoietin useful for as a recombinant drug?

Answer 42

Renal anaemia and myelodysplasia

Question 43

What gives the RBC membrane its rigid shape?

Answer 43

The two strands of Sceptrin

Question 44

Describe the RBC membrane

Answer 44

Lipid bi-layer with protein bound into it

Question 45

Describe what makes a Haemoglobin

Answer 45

Four globin chains and four haem molecules. 2 Alpha-like chains (Ch 16), Zeta (Early foetal) then Alpha 2 Beta-like chains (Ch 11), Epsilon then Gamma, then Delta, then Beta

Question 46

What makes a Haemoglobin for an adult?

Answer 46

2 Alpha and 2 Beta

Question 47

What makes a Haemoglobin for an early foetal?

Answer 47

2 Alpha and 2 Gamma

Question 48

Define Thalassaemia

Answer 48

An inherited defect in globin chain production

Question 49

Define Sickle Cell disease

Answer 49

One amino acid change in beta chain

Question 50

What is Myoglobin?

Answer 50

In skeletal muscle. It is a store of Oxygen for immediate use.

Question 51

Describe the structure of Myoglobin

Answer 51

One haem unit, one globin chain

Question 52

How pH is measured?

Answer 52

pH is measured on log scale

Question 53

Why is acid-balance important?

Answer 53

Enzymes work optimally at physiological Ph Cell membranes become leaky in acidosis Neurones become less able to transmit in acidosis (hyperactive in alkalosis)

Question 54

State the buffer systems of the human body

Answer 54

1. Bicarbonate (60% of buffer capacity) - A decrease in pH/increase in H+ will drive equation to the left 2. Haemoglobin (30% of buffer capacity) - H+ combines with Haemoglobin after loss of Oyxgen and Low pH decreases Haemoglobin affinity for O2

Question 55

What is the catalyst for the bicarbonate buffer system?

Answer 55

Carbonic Anhydrase (CA)

Question 56

What is the equation for the bicarbonate buffer system?

Answer 56

CO2 + H2O ---> H2CO3 ---> H+ + HCO3-

Question 57

What is the equation for the haemoglobin buffer system?

Answer 57

CO2 + Hb ---> HbCOO- + H+

Question 58

What causes RBC loss or destruction?

Answer 58

As RBC age, membrane becomes more rigid and the loss of glycolytic enzymes increases and neoantigents exposed on cell surface Some are lost from GI tract/into soft tissues/menstrual loss Some RBC destroyed within body