16. Haemopoiesis Flashcards Preview

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Flashcards in 16. Haemopoiesis Deck (40)
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1
Q

What is haemopoiesis

A

production of blood cells and platelets, which occurs in the bone marrow.

2
Q

What two things can the hemocytoblast/ haemopoietic stem cell differentiate into?

A
  1. Common myeloid progenitor

2. Common lymphoid progenitor

3
Q

What is the difference in differentiating ability of Haemopoietic stem cells and Common progenitors.

A
  • Haemopoietic stem cells have the ability to self replicate and differentiate further
  • Common progenitors only have the ability to differentiate into lineage bound
4
Q

Will the cells found in the bone marrow end up in blood and if not what happens to them?

A
  • Not all cells found in the bone marrow will end up in the blood
  • Some will undergo programmed cell death (apoptosis)
5
Q

Give 4 features of red blood cells ad explain how the features help with their function?

A
  • Biconcave shape to increase surface area for diffusion of gases
  • No nucleus/minimal organelles to maximise oxygen holding capabilities
  • No mitochondria to ensure oxygen is not used up by erythrocyte
  • Haemoglobin to increase affinity of oxygen binding (made from iron)
6
Q

What is Erythropoiesis?

A

process which produces red blood cells, which is the development from erythropoietic stem cell to mature red blood cell.

7
Q

Describe the process of Erythropoiesis

A
  • Erythroblasts (immature blood cell) start of with large nucleus, prominent nucleoli and large amounts of RNA
  • Gradually nucleus shrinks and is removed along with majority of RNA
  • forms RETICULOCYTES - The final step before a mature erythrocyte -once the nucleus has been removed
  • Only a small amount of RNA remains to help make haemaglobin
  • This is removed in 1-2 days
8
Q

What happens during blood loss?

A
  • The kidney senses tissue hypoxia
  • The kidney increases secretion of erythropoietin - a hormone
  • Erythropoietin is a glycoprotein produced by the kidney to increase levels of red blood cells
  • Acts to stop programmed cell death (apoptosis) of erythrocyte progenitors
9
Q

What is Granulopoiesis?

A

production of granulocytes from myeloblast

10
Q

What are the 3 granulocytes?

A

Basophils, neutrophil, eosinophil

12
Q

Why are granulocytes so called?

A

due to the presence of granules within their cytoplasm

13
Q

What is the function of granulocytes?

A

All act to mediate inflammatory reactions in the body

• All act by releasing cytokines, interleukins, leukotrienes

14
Q

What happens during Granulopoiesis?

A

All 3 lineages go through the process of:
• Nuclear condensation and lobulation
• Formation/increased numbers of granules

15
Q

Give two features of Neutrophils

A

Multilobed nucleus

• 3 types of granules

16
Q

What is the function of neutrophils?

A

Kill pathogens by:
• Phagocytosis
• act as the middle person i.e signalling and antigen presentation
• Neutrophil Extracellular traps (NETS)
• Respiratory burst - rapid release of reactive oxygen species (superoxide radical and hydrogen peroxide) - to degrade internalized particles and bacteria.

17
Q

Which hormone stimulates neutrophil production?

A

COLONY STIMULATING FACTOR (G-CSF)

18
Q

What secretes the G-CSF hormone and when are they secreted?

A

Secreted by multiple immune cells in the body and endothelial cells
• Usually released in response to inflammation

19
Q

What does the G-CSF hormone do?

A
  • Acts on the bone marrow to increase the number of circulating neutrophils
  • Increases the speed at which nuetrophils mature as well as the numbers
20
Q

Five two features of basophils?

A
  • Bilobed nucleus
  • Purple granules (stained due to basic dye)
  • Granules contain histamine and heparin
21
Q

What is the role of basophils?

A
  • Release histamine to trigger inflammation

* Mediate hypersensitivy reactions (eg asthma)

22
Q

Give two features of EOSINOPHILS

A
  • 2 nucleur lobes

* Spheric granules- eosinophilic (acid-loving) granules

23
Q

What are the roles of eosinophils?

A
  • Phagocytose pathogens

* Fight parasitic worms and have a role in inflammation/allergy

24
Q

What do the eosinophil granules contain?

A
  • antihelminthic proteins such as major basic protein and eosinophilic cationic protein
  • Cell component destroying enzymes (eg phosphlipases and acid hydrolases)
25
Q

Are monocytes granulocytes And why?

A

No • Monocytes are agranulocytes - absence of granules in their cytoplasm,

26
Q

What are monocytes called in tissue?

A

• Monocyte in the blood- macrophage in the tissue

27
Q

What are the function of monocytes/macrophages?

A
  • Phagocytose pathogens, cell debris and senescent cells

* Present foreign antigens i.e raise the alarm

28
Q

What is the shoe of nucleus in monocytes/macrophages?

A

• Unilobular ”horseshoe” shaped nucleus

29
Q

What is thrombopoiesis?

A

• Thrombopoiesis is the production of thrombocytes (platelets) from megakaryocytes

30
Q

Which hormone controls production of thrombocytes And where is it produced?

A

thrombopoietin from the liver

31
Q

What is the function of platelets?

A

Function to stop bleeding and mediate haemostasis

32
Q

Give 3 features of platelets(thrombocytes)?

A
  • Biconvex shape
  • No nucleus- just cytoplasm
  • contains vast amount of proteins and clotting factors
33
Q

What is Lymphopoiesis?

A

Production of lymphocytes

34
Q

What are the. Types of lymphocytes?

A
  • B Lymphocyte
  • T Lymphocyte
  • (Natural killer cell)
35
Q

What is the main function of b lymphocytes?

A

production of antibodies

36
Q

Where does maturation of b lymphocytes occur?

A

in the bone marrow and then in:
• Intestines (peyers patches)
• Spleen
• Lymph nodes

37
Q

Which immunity are b lmphocytes involved in?

A

humoral adaptive immunity

38
Q

What is the main function of t lymphocytes?

A

Kill virus-infected cells, neoplastic cells and transplanted tissue
• Carry out cell-mediated immunity
• Activate B cells to make antibodies using IL 4

39
Q

Which hormone is involved in the production lymphocytes?

A

Interleukins

40
Q

Describe the structure of t lymphocytes

A

Large nucleus with small rim of cytoplasm

41
Q

Where do T cells mature?

A
  • T cells start off in the bone marrow or fetal liver and then will migrate to the thymus to mature
  • After this they will migrate to secondary lymhoid organs where they will wait until activation