L5 Leucocytes and Inflammation

Question 1

What is haematopoeisis?

Answer 1

production of blood cells

Question 2

What is leucopoeisis?

Answer 2

production of leucocytes

Question 3

What happens during haematopoeisis?

Answer 3

Increasing specialisation (commitment)
-Decreasing plasticity

Question 4

What are the two major leucocyte lineages?

Answer 4

Lymphoid (Lymphocytes) – small, bland-looking cells

Myeloid – larger cells; most have prominent cytoplasmic granules and are called granulocytes

Question 5

What is the activated function of macrophage?

Answer 5

Phagocytosis and activation of bactericidal mechanisms

Antigen presentation

Question 6

What is the activated function of dendritic cells?

Answer 6

Antigen uptake in peripheral sites

Antigen presentation in lymph nodes

Question 7

What is the activated function of neutrophils?

Answer 7

Phagocytosis and activation of bactericidal mechanisms

Question 8

What is the activated function of eosinophils?

Answer 8

Killing antibody coated parasites

Question 9

What is the activated function of mast cells?

Answer 9

Release granules containing histamine and other active agents

Question 10

Lymphoid lineage

Answer 10

Small, bland-looking cells

All look similar by basic light microscopy

Various types with different functions

Special stains needed to resolve
different types on light microscopy

Question 11

B cells

Answer 11

produce antibodies

Antibodies are proteins that bind to antigens

Particularly important in dealing with extracelllular infections such as bacteria

Question 12

T cells

Answer 12

Precursors are produced in the bone marrow; complete maturation in the thymus during gestation

CD8 T cells are particularly important in dealing with intracellular infection (viral infection)

CD4 (helper) T cells are needed to direct the activity of the immune system

Question 13

What is a cytokines?

Answer 13

Cytokines are small proteins released by cells that have an effect on another cell
They are important for communication between cells of the immune system and between immune system cells and other cells and tissues

Question 14

What is a chemokine?

Answer 14

Very different protein structure
Very different receptors
Mainly involved in temporal and spatial organisation

Question 15

What are the cardinal features of inflammation?

Answer 15

Pain (Dolor)
Heat (Calor)
Redness (Rubor)
Swelling (Tumor)
(Loss of function – added later)

Question 16

How does inflammation occur?

Answer 16

For many infections, the first step is to breach a barrier such as the skin and enter the tissue

The first cell that will be met is a tissue macrophage

Tissue macrophages will engulf and kill organisms by a process called phagocytosis

Question 17

What is phagocytosis?

Answer 17

Organism phagocytosed into a phagosome, which then fuses with a lysosome containing digestive enzymes. The organism is killed in this ‘phagolysosome’ by low pH, digestive enzymes, toxic free radicals and hydrogen-oxygen products

Question 18

Cytokines involved in local inflammation

Answer 18

Tumour necrosis factor alpha (TNF-alpha)
Interleukin-1 (IL-1)
Interleukin-6 (IL-6)

Question 19

The role of chemokines in local inflammation

Answer 19

Attracting other cells, particularly neutrophils
Acting on blood vessels to cause:
Vasodilation
Increased permeability
Increased adhesion molecules on blood vessel endothelium

Question 20

What are the outcomes of acute inflammation?

Answer 20

Resolution: insult removed, tissue heals completely
Fibrosis: insult removed, but tissue is scarred
Chronic: insult cannot be removed
Abscess formation

Question 21

Benefits of inflammation

Answer 21

Amplifies the immune response
Small stimulus creates large local & systemic response

Focuses the immune response
Brings in cells required to contain infection and activate healing process when infection is cleared

Activates the next stages of immunity (B cells/ T cells)
This is the next line of defence, and also how the immune system learns (memory)

Question 22

Negatives of inflammation

Answer 22

May damage healthy tissue
May be activated inappropriately (without infection)
May be activated in an uncontrolled manner: septic shock