Physiology of Haematopoiesis Flashcards Preview

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Flashcards in Physiology of Haematopoiesis Deck (117)
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1

What is haematopoiesis?

The process through which all types of mature blood cell are produced

2

What are haematopoietic stem cells (HSCs)?

Multipotent cells characterised by their ability to 'self-renew' (proliferate) and mature into fully differentiated cells of any of the haematopoietic lineages

3

What is the importance of HSCs?

They sustain blood cell production throughout life

4

What are the principle haematopoietic lineages?

- Erythroid/megakaryocytic
- Granulocyte/macrophage
- Lymphoid

5

What does the erythroid/megakaryocytic lineage give rise to?

- RBCs
- Platelets

6

What does the granulocyte/macrophage lineage give rise to?

Granulocytes and monocytes

7

What does the lymphoid lineage give rise to?

- B cells
- T cells
- NK cells

8

What can HSCs be characterised by?

Proteins expressed on the cell membrane

9

What can the cell markers on the membrane of HSCs be utilised for clinically?

To purify HSC for clinical applications, e.g. haematopoietic stem cell transplant

10

What are the HSCs and their progeny controlled by?

A network of interactions with haematopoietic growth factors and cellular components of the haematopoietic micro-environment that maintain balanced blood cell production

11

When does primitive haematopoiesis begin?

In the first few weeks of embryonic life

12

Where does primitive haematopoiesis begin?

In the yolk sac

13

What does primitive haematopoiesis give rise to?

Mainly RBCs

14

What is primitive haematopoiesis replaced by?

Definitive hematopoiesis

15

When is primitive haematopoiesis replaced by definitive haematopoiesis?

5-6 weeks gestation

16

What does definitive haematopoiesis produce?

Has the capacity to produce all blood cell cycles

17

Where do definitive hematopoietic stem cells develop?

In the aorta-gonad-mesonephros (AGM) region of the dorsal aorta

18

Where do HSCs migrate after developing in the AGM?

To the fetal liver and spleen

19

When do HSCs migrate from the AGM region to the fetla liver and spleen?

6-7 weeks gestation

20

What is the primary site of haematopoiesis from 6-7 weeks gestation?

The liver

21

What happens to the site of haematopoiesis in the third trimester?

It progressively increases in the bone marrow

22

What is the site of haematopoiesis after birth?

Bone marrow

23

Where in the bone marrow does haematopoiesis occur?

Initially it occurs in all areas of the bone marrow, but becomes restricted to axial skeleton and proximal ends of long bones later in childhood

24

What are RBCs?

Specialised cells that mainly function to deliver oxygen to the tissues and remove carbon dioxide

25

What shape are RBCs?

Biconcave

26

What cellular structure do RBCs lack?

Nucleus

27

What do RBCs have a lot of?

The oxygen-carrying protein haemoglobin

28

What does each molecule of haemoglobin consist of?

4 globin chains and a central iron containing haem group

29

What happens to the composition of Hb during fetal development?

It changes in an ordered sequence

30

What are the first globin chains produced?

Epsilon and zeta