Physiology

Question 1

What is haematopoiesis?

Answer 1

The production of blood cells

Question 2

What are mature blood cells produced from?

Answer 2

Precursor stem cells

Question 3

What are stem cells?

Answer 3

Cells from the mesoderm that can self-renew, proliferate and differentiate into any type of blood cell

Question 4

Once a stem cell has started down a lineage pathway can it go back?

Answer 4

No

Question 5

What are the sites of haematopoiesis at birth?

Answer 5

Mainly bone marrow

Plus the liver and spleen when needed

Question 6

What are the sites of haematopoiesis in adulthood?

Answer 6

Only the axial skeleton - skull, ribs, sternum, pelvis, proximal ends of femur

Question 7

What are the types precursor cell that stem cells can differentiate into?

Answer 7

Common myeloid precursor

Common lymphoid precursor

Question 8

What do common lymphoid precursors differentiate into?

Answer 8

B cells, T cells and NK cells

Question 9

What do common myeloid precursors differentiate into?

Answer 9

Megakaryocyte/erythroid precursor - then platelets/RBC

Granulocyte/macrophage precursor - then granulocytes/macrophage

Question 10

What are the granulocytes?

Answer 10

Basophils, eosinophils, neutrophils

Question 11

What is the main function of red blood cells?

Answer 11

Carry oxygen

Question 12

What is the main function of platelets?

Answer 12

Stop bleeding

Question 13

What is the main function of white blood cells?

Answer 13

Fight infection

Question 14

What is erythropoiesis?

Answer 14

The production of RBCs

Question 15

What stimulates erythropoiesis?

Answer 15

Reduced oxygen carrying capacity in the blood stimulates erythropoietin production and release from the kidneys

Question 16

What are reticulocytes?

Answer 16

The immediate precursors to red blood cells

Question 17

What are the features of reticulocytes?

Answer 17

No nucleus
Larger than RBCs
Contain RNA - making them polychromatic

Question 18

What are the features of mature RBCs?

Answer 18

Biconcave shape
No nucleus
No mitochondria

Question 19

What is the consequence for RBCs having no nucleus?

Answer 19

Can’t divide or self-renew

Question 20

What is the energy source for RBCs?

Answer 20

Glycolysis

Question 21

What is the lifespan of mature RBCs?

Answer 21

120 days

Question 22

Which organs get rid of RBCs at the end of their lifespan?

Answer 22

Spleen

Liver

Question 23

What is the structure of haemoglobin?

Answer 23

4 globin chains (2 alpha, 2 beta in HbA - adult)

Haem group made of Fe2+ and a porphyrin ring

Question 24

Why does the haem group have Fe2+ not Fe3+?

Answer 24

Oxygen does not bind to Fe3+

Question 25

What is the process of red cell destruction?

Answer 25

Aged red cells are taken up by macrophages Red cell contents are recycled Globing chains are recycled to amino acids The heam group is broken down to iron and bilirubin The bilirubin is taken to the liver and conjugated, then excreted in bile

Question 26

What benefits does glycolysis have for RBCs?

Answer 26

Prevents from oxidative damage and protects from free radicals

Question 27

What is the rate limiting enzyme in glycolysis?

Answer 27

Glucose-6-phosphate

Question 28

How do platelets form?

Answer 28

Pockets of cytoplasm 'bud off' from megakaryocytes

Question 29

What is the morphology of megakaryocytes?

Answer 29

Large cells with large lobulated nucleus

Question 30

What is the lifespan of platelets?

Answer 30

7-10 days

Question 31

What are the white blood cells?

Answer 31

``` Neutrophils Eosinophils Basophils Monocytes Lymphocytes ```

Question 32

What is the morphology of neutrophils?

Answer 32

Multi-segmented nucleus Neutral staining granules Express myeloperoxidase

Question 33

What is the function of neutrophils?

Answer 33

Phagocytosis - kill by releasing granule contents | Recruitment of other immune cells

Question 34

What can cause neutrophilia?

Answer 34

Acute inflammation - infection, trauma, infarction Pregnancy Drugs - steroids

Question 35

What can cause neutropenia?

Answer 35

Aplastic anaemia Pancytopenia Drugs - clozapine, carbimazole

Question 36

What is the morphology of eosinophils?

Answer 36

Bi-lobed (horseshoe) | Orange/red granules

Question 37

What is the function of eosinophils?

Answer 37

Hypersensitivity | Fight against parasitic infections

Question 38

What can cause eosinophilia?

Answer 38

Churg-Strauss syndrome Atopy Parasitic infections Hodgkin's

Question 39

What is the morphology of basophils?

Answer 39

Large deep purple granules that can be so abundant they obscure the nucleus

Question 40

What is the function of basophils?

Answer 40

Uncertain Circulating version of tissue mast cell Mediates hypersensitivity reactions Granules contain histamine

Question 41

What are basophils increased in?

Answer 41

CML | Polycythaemia rubra vera

Question 42

What is the morphology of monocytes?

Answer 42

Large single nucleus (kidney shaped) Faintly staining granules Often vacuolated (contain white circles) Large cytoplasm

Question 43

What is the function of monocytes?

Answer 43

Circulate for a few days then enter tissues and become macrophages As macrophages - phagocytes, antigen presentation Attract other cells

Question 44

What are monocytes increased in?

Answer 44

``` Chronic bacterial infections SLE RA Lymphoma Leukaemia ```

Question 45

What is the morphology of mature lymphocytes?

Answer 45

Small Condensed nucleus Rim of cytoplasm

Question 46

What is the morphology of activated (atypical) lymphocytes?

Answer 46

Large Plentiful blue cytoplasm Extend round neighbouring red cells 'Open' nucleus with chromatin pattern

Question 47

What is the function of lymphocytes?

Answer 47

Lots of types and functions | Coordinate response to infection

Question 48

What can cause lymphocytosis?

Answer 48

Infection Malignancy Hyposplenism