Leucocytes

Question 1

What are leucocytes?

Answer 1

White blood cells

Question 2

Define the term Haematopoeisis

Answer 2

The production of blood cells

Question 3

Define the term Leucopoeisis

Answer 3

The production of leucocytes

Question 4

Explain the journey from a stem cell to blood cells

Answer 4

Haematopoeisis: Stem cells undergoes differentiation.
This leads to increased specialisation(commitment) but decreased plasticity
This forms a mature cell ( erythrocyte, leucocyte and platelets) which leaves the bone marrow and enters the bloodstream

Question 5

A family tree of cell division is called?

Answer 5

Lineage

Question 6

List the 2 major leucocyte lineage with explanation

Answer 6

1. Lymphoid(Lymphocytes)- small bland looking cells, e.g B cell, T cell and NK cell
2. Myeloid- larger cells. They have cytoplasmic granules called granulocytes

Question 7

List the haematopoiesis lineage

Answer 7

1.Haematopoietic stem cell
into
2. Lymphoid progenitor and 3.Myeloid progenitor
Lymphoid progenitor splits into 4. B cells 5. T cells 6. NK Cells

Myeloid progenitor splits into 7. Granulocytes/monocyte/ precursor mast cell and 8. Erythrocytes progenitor/ Megakaryocyte

Granulocytes differentiates to form neutrophils, eosinophils and basophils

Monocyte forms macrophage

Precursor mast cell forms mast cell.

Erythrocyte progenitor forms erythrocyte

Megakaryocyte forms platelets

Plasma cells are formed from B cells

Question 8

Give 5 examples of Lymphoid Tissue (Collection of leucocyte cells)

Answer 8

1. Tonsil
2. Right + left subclavian vein
3. Lymph node
4. Thymus
5. Heart
6. Kidney
7. Spleen
8. Appendix
9. Bone Marrow

Question 9

List 3 functions of macrophage cells

Answer 9

1. Phagocytosis
2. Antigen presentation
3. Activation of Bactericidal mechanism

Question 10

List 2 functions of dendritic cells

Answer 10

1. Antigen uptake in peripheral sites

2. Antigen presentation in lymph nodes

Question 11

List 2 functions of neutrophil

Answer 11

1. Activation of bactericidal mechanism
2. Phagocytosis
   Side note: Neutrophil has one nucleus but it is multiload

Question 12

1 Function of Eosinophil

Answer 12

Killing of anti-body coated parasites

Question 13

1 Function of Mast cell

Answer 13

Release of granules containing histamines

Question 14

3 types of Lymphocytes

Answer 14

1. B- cells- produces antibodies
2. T- Cells- CD4 helper T cells and CD8 killer T cells
3. Natural Killer(NK) Cells

Question 15

What are Cytokines

Answer 15

Cytokines are small proteins released by cells that have an effect on another cell

Question 16

List 3 actions of Cytokines

Answer 16

1. Autocrine
2. Paracrine
3. Endocrine

Question 17

What are Chemokines

Answer 17

Chemokines are small proteins released by cells. They have different protein structure/receptors to Cytokines.
They are involved in Spatial organisation. E.g CXCL8 attracts neutrophils to sites of infection

Question 18

What is Juxtacrine signalling

Answer 18

Cell-cell contact communication between 2 cells

Question 19

What are the 5 cardinal features of inflammation

Answer 19

1. Calor (Heat)
2. Dalor (Pain)
3. Rubor (Redness)
4. Tumor (Swelling)
5. Lack of function

Question 20

After successful breach of the skin barrier. What leucocyte cell first approaches the pathogen?

Answer 20

Tissue Macrophage
Engulfs and kills the pathogen by phagocytosis.
Then undergoes Antigen presentation

Question 21

What 2 type of cells can perform phagocytosis?

Answer 21

1. Macrophage

2. Neutrophils

Question 22

Describe the process of Phagocytosis

Answer 22

1. Pathogen is phagocytosed into a phagosome.
2. Phagosome fuses with low pH(acidic) lysosome digestive enzyme to form phagolysosome
3. This produces toxic free radicals and hydrogen peroxide

Question 23

Phagocytosis causes the release of soluble mediators. List the 2 main soluble mediators

Answer 23

1. Cytokines

2. Chemokines

Question 24

List 3 examples of Cytokines

Answer 24

1. Tumour Necrosis Factor (TNF- alpha)
2. Interleukin-1 (IL-1)
3. Interleukin-6 (IL-6)

Question 25

Give an example of Chemokines

Answer 25

1. CXCL8

Question 26

Besides the attraction of neutrophils, | List 3 effects soluble mediators has on blood vessels

Answer 26

1. Vasodilation 2. Increased Permeability - junction between endothelial cell widens. 3. Increased adhesion molecules on blood vessel endothelium

Question 27

Define local inflammation

Answer 27

The response is present in the site of infection.

Question 28

Define systemic inflammation

Answer 28

The response has spread beyond the original site of infection to other parts of the body

Question 29

Cause of systemic inflammation

Answer 29

During more serious infections. Cytokines are released into the bloodstream and can have an effect on distant tissues

Question 30

Symptoms/Features of Systemic inflammation

Answer 30

Fever, fatigue, muscle pain, anorexia | prolonged systemic inflammation can lead to loss of muscle and fat

Question 31

List 4 organs cytokines effect during a systemic inflammation

Answer 31

1. Liver - activation of opsonisation 2. Bone marrow - causes neutrophil mobilization for phagocytosis 3. Hypothalamus 4. Fat and Muscle - both causes an increase in temperature. Pathogen replication decreased/Increased antigen processing+ specific immune response

Question 32

List 4 outcomes of acute inflammation

Answer 32

1. Resolution- insult removed, tissue heals completely 2. Fibrosis- insult removed, but tissue is scarred 3. Chronic- insult cannot be removed 4. Abscess Formation

Question 33

3 advantages of inflammation

Answer 33

1. Amplifies the immune response- small stimulus creates large local and systemic response 2. Focuses the immune response - bring in specific cells that are needed 3. Activates the next stages - B cells/T cells

Question 34

3 disadvantages of inflammation

Answer 34

1. Healthy tissue may be damaged- bystander damage 2. May be activated inappropriately (without an infection) 3. May be activated in an uncontrolled manner e.g meningitis