Infection: The innate immune response Flashcards Preview

ESA 3 > Infection: The innate immune response > Flashcards

Flashcards in Infection: The innate immune response Deck (14)
Loading flashcards...
1
Q

What are the general roles of the immune system?

A
  • pathogen recognition
  • containing and eliminating the infection
  • regulating itself so there is minimum damage to the host
  • remembering pathogens to prevent recurrent disease
2
Q

What are the 4 types of innate barriers that prevent entry and limit growth of pathogens?

A

Physical barriers
Physiological barriers
Chemical barriers
Biological barriers

3
Q

Give some examples of physical barriers

A
  • Skin
  • Mucous membranes (line every entry to body)
  • Bronchial cilia that expel trapped microbes
4
Q

Give some examples of physiological barriers

A
  • diarrhoea
  • vomiting
  • coughing
  • sneezing
    All work to clear the pathogen
5
Q

Give some examples of chemical barriers

A
  • low pH in skin, stomach, vagina
  • IgA in tears, saliva, mucous (binds to microbe to stop it attaching)
  • lysozyme
  • mucus
6
Q

Give some examples of biological barriers

A
  • normal flora present in points of entry eg mouth, vagina, skin, GI tract (absent in all internal organs and tissues)

Compete with pathogens, produce antimicrobials and synthesis vitamins eg K and B12

7
Q

Which patients are at high risk from serious infection from bacteraemia

A

Asplenic pts at high risk from encapsulated bacteria
Pts with damaged or prosthetic heart valves
Pts with previous infective endocarditis

8
Q

Give some examples of diseases than can arise when normal flora is depleted by antibiotics

A

In the intestine: sever colitis with C difficile

In the vagina: thrush from overgrown candida albicans caused by a raise in pH

9
Q

What are the main types of phagocytes and what is their role?

A

Macrophages: present in all organs. Phagocytose, present antigens to T cells and produce cytokines.

Monocytes: present in blood. Recruited to infection site where they differentiate into macrophages.

Neutrophils: present in blood. Recruited by chemokines to site of infecrion. Phagocytose pyogenic bacteria - staph aureus and strep pyogenes

10
Q
What is the function of:
Mast cells
Eosinophils
Natural Killer cells
Dendritic cells
A

Mast cells: allergic responses
Eosinophils: defence against parasites
Natural killer cells: kill abnormal host cells (viral infected or malignant)
Dendritic cells: present antigens to T cells (link innate and adaptive immunity)

11
Q

How do phagocytes recognise pathogens?

A

On the pathogen there are Pathogen Associated Molecular Patterns (PAMPs)
These are recognised by Pathogen Recognition Receptors (PRRs) on phagocytes

Opsonins

12
Q

What is opsonisation?

A

Antibodies or complement (both known as opsonins) bind to the pathogen and are recognised by the phagocytes as pathogens so can be destroyed

13
Q

What causes inflammation?

A

Mast cells recognise PAMPs which causes them to release histamine, this increases vascular permeability and causes vasodilation producing an inflammatory response (rubor, dolor, calor, tumor)

14
Q

What are the 2 complement pathways?

A

The complement cascade either:

  • causes opsonisation of the pathogen
  • destroys the pathogen by rupturing its membrane

Decks in ESA 3 Class (96):