Block 10 - Blood and Immunology

Question 1

What makes up the immune system?

Answer 1

Immune organs:
- Thymus, lymph nodes, spleen

White blood cells:
- Bone marrow > specialisation > blood, lymph, muscosa, migration into tissues

Circulating proteins (acellular components)

Part of it is innate (born with) and some is acquired (developed when exposed to microbes)

Question 2

What makes up innate immunity?

Answer 2

1) physical barriers:
. epithelial layers
. hair
. fluids
. mucus
. cillia

2) cellular components
. white blood cells (WBC - leukocyes)
- made in bone marrow
- found in blood and lymph tissue
- collect at site of infection
. phagocytes (engulf and degrade)
- increase upon infection
- short lived (make mucus and pus green)
- kill bacteria and fungi
- e.g. macrophages, monocytes, dendritic cells, mast cells
. lymphocytes (same family as T and B cells)

3) humerol (protein) responses
. Secreted macromolecules
- secretions, e.g. antibacterial peptides, muscins
- cytokines, proteins that akter the behaviour of other cells
- chemokines, proteins that attract other cells

. rapid
. non-specific
. barrier
. first line of defence

Question 3

What makes up acquired immunity?

Answer 3

Cellular defences:
- cytotoxic T cells
- T helper cells
- B lymphocyte

Acellular defences:
- antibodies (produced by B cells)
- cytokines

Can learn to recognise specific pathogens (adaptive immunity)

Can ignore human molecules (self tolerance)

Question 4

What are pathogen associated molecular patterns (PAMPs)?

Answer 4

Part of the innate immune response

• Repeating molecules common in pathogens that are absent from human cells
  . e.g lipopolysaccharides, peptidoglycan, teichoic acid, flagella proteins
• Recognised by receptors called PAMP recognition receptors (PRR) - not specific for a particular microbe

Question 5

What are damage associated molecular patters (DAMPs)?

Answer 5

Part of the innate immune response.

Necrosis > DAMPs
- Unplanned, accidental cell death
- Caused by injury, infection etc
- Involves inflamation, alerts immune system

Apoptosis > no DAMPs
- Programmed cell death
- Natural mechanism without inflammation

Question 6

What happens when there is an immune deficiency?

Answer 6

• More frequent infections
• More damage from each infection
• Damage from unbalanced immune response unrelated to infection (inflammation, allergy, autoimmunity)
• Increased risk of cancer

Question 7

List 4 examples of disordered immune response

Answer 7

1) Asthma - inappropriate inflammation
2) Allergy - autoimmune diseases
3) Arthritis - immunodeficiency disorders
4) Lupus - hypersensitivity reactions

Question 8

What stimulates inflammation in response to infection?

Answer 8

• PAMPs
• DAMPs
• Toll-like receptors, scavener receptors
• Neutrophils, macrophages, dendritic cells

Creates pus:
- dead neutrophils
- protein rich fluids
- macrophages phagocytose dead neutrophils

Question 9

Where can inflammation occur in the absense of infection?

Answer 9

Anywhere with necrotic injury:
- ischeamia
- physical injury
- heat or chemical burn
- toxic injury

Osteoarthritis, inflammation causes painful and stiff joints - causes more damage.

Atherosclerosis and coronary artery disease

Question 10

How does inflammation work in relation to cancer?

Answer 10

Elimination:
- response to tissue damage cause by cancer cells
- phagocytosis of dead cells
- block angiogenesis

Equilibrium
- selection of susceptible varient cells

Escape
- resistant cells proliferate - maligancy

Question 11

What causes redness and heat in inflammation?

Answer 11

Blood flow.

• vascular beds between arteriole and venule
• shunt and throughfare channels
• chemical mediators of inflammation open the sphincters
  . opening of dormant cappilaries