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1

what is the need for an immune system?

Protection against infectious organisms

2

Name some types of infectious organisms.

-Bacteria
-Viruses
-Fungi
-Protozoans
-worms

3

what are the 2 major systems of immunity ?

-innate immunity
-adaptive immunity

4

what are the features of innate immunity?

-“A first line of defence”
-Present at birth
-Responds rapidly
-Has no specificity
-Has no memory

5

what factors make up innate immunity?

Barriers, cells, soluble factors

6

What are the two types of barriers?

-Physical
- Chemical

7

Name 2 physical barriers of innate immunity.

1. Impermeable outer surface
e.g. skin,epithelial cell layer lining mucosal surfaces
2. Cilia in nasal passages and bronchi

8

Describe the physical barrier in the nasal passages.

-airborne bacteria are trapped on mucus secreted by goblet cells
-cilia waft the bacteria towards mouth and nose

9

Name 3 chemical barriers of innate immunity.

1. Acidity in stomach
2. Alkaline secretions
3. Lysozyme in tears

10

Name a biological barrier of innate immunity.

Competition with commensal organisms

11

Describe the mechanisms of innate immunity in the gastrointestinal tract.

-most pathogens are destroyed by the low pH of the stomach
-the few pathogens that reach the large bowel must compete with billions of harmless gut bacteria

12

What are the 3 types of cells in innate immunity?

-Phagocytes
-NK cells
-Eosinophils

13

Name 3 types of phagocytes.

Monocytes,macrophages and neutrophils

14

Give a simple description of phagocytosis.

A phagocyte binds to bacterium. The bacterium is engulfed in the phagocyte. The bacterium is inside a membrane bound vescicle which fuses with a lysosome which degrades the bacteria.

15

What is the role of NK cells ?

Kill tumour cells and virally-infected cells

16

What is the role of eosinophils?

Attack and kill parasites

17

what are the innate immunity soluble factors?

-Lysozyme
-Complement
-Cytokines particularly Interferons
-Acute phase proteins (concentration goes up during infection)

18

How do components of the innate system act together?

They cooperate together and also cooperate with the adaptive immune system

19

what are the features the adaptive immune system?

-Slow to start
-Adaptive
-Highly specific
-Has memory
-Recognition of self and non-self
-Humoral and cellular components
that work in concert

20

In humoral immunity , what are antibodies?

-Specific proteins produced against pathogens
-Produced by B lymphocytes

21

Describe cellular immunity..

Mediated by lymphocytes which recognise specific pathogenic structures called antigens

22

What cells are involved in cellular immunity?

-B lymphocytes
-T lymphocytes
-Helper T cells
-Cytotoxic T cells

23

What is the role of Helper T cells?

help B cells produce antibodies

24

What is the role of cytotoxic T cells?

destroy own cells which have been infected eg with virus

25

what does adaptive immunity provide?

Immunological memory

26

What is the difference in the number of days for peak antibody production between 1st and 2nd response?

-10 days for 1st response and 4 days for 2nd response
- (maximum number of antibodies is much higher during the second response)

27

what are the 2 roles of the immune system?

-Recognition function-identifies a substance or body (antigen) as foreign
-Effecter function -removes foreign invader

28

What is an antigen?

any substance which elicits an immune response

29

What are the portions recognised?

epitope or antigenic determinant

30

What do macro-molecule contain?

antigenic determinants