Innate Immunity: First & Second Line of Defence

Question 1

Describe the physical barriers of an animal

Answer 1

*Skin
*Lining of the respiratory, gastrointestinal and urogenital tract.
*Mucus secreting membranes
*Membranes lined with cilia

Question 2

Describe the physical barriers of a plant

Answer 2

*Cell wall in plant cells
*Bark in trees
*Ability to close stomata
*Positioning of leaves

Question 3

Describe the chemical barriers of an animal

Answer 3

*lysozymes, enzymes & fatty acids (e.g. tears, sweat)
*Low pH (stomach & vagina)
*Surfactants (lungs)

Question 4

Describe the chemical barriers of a plant

Answer 4

*Chemicals inhibit growth & development of pathogens:
-released into environment
-remain in plant
*Defensins: small stable peptides can inhibit development of fungi, bacteria & viruses.

Question 5

What is microbial barriers

Answer 5

*“good” bacteria on the skin and in the digestive system

Question 6

What are the features of the innate immune response

Answer 6

*Non-specific
*Barriers keep pathogens out; cells & molecules to indiscriminately destroy pathogens that get in.
*A rapid response
*No memory of infection & has no faster clearance on re-infection.

Question 7

Describe complement proteins

Answer 7

*A system of 20 proteins produced by liver & circulates in the blood system.
*Bind cellular pathogens & target them for destruction.
*Release chemical signals to attract phagocytes.
*Activated as part of the innate immune response

Question 8

Draw the ‘phagocytosis’ process

Answer 8

*refer to diagram booklet

Question 9

Describe ‘The Inflammatory Response’

Answer 9

*Characterised by redness, swelling, heat, pain and puss.
*Response to cut through skin or presence of pathogen.
*Mechanism ensuring macrophages, mast cells, neutrophils and complement proteins arrive to location of pathogen.

Question 10

Draw ‘The Inflammation Response’ process

Answer 10

*Refer to diagram booklet

Question 11

Define ‘antigens’

Answer 11

*Unique molecules found in all cells that is recognised by immune system.

Question 12

Define ‘self antigens’

Answer 12

*Found in own cells & recognised as belonging by immune system.

Question 13

What is the difference between MHCI AND MHCII?

Answer 13

*MHCI: on all cells
*MHCII: on antigen presenting cells (e.g. macrophage, dendritic cells, B lymphocytes).