7b- The first line of Defence

Question 1

What is the innate immune system, and what does it consist of?

Answer 1

The innate immune system consists of 2 different defenses, first and second lines of defense.

Question 2

What do both the first and second lines of defense involve?

Answer 2

Both mechanisms involve a non specific response to foreign antigens, reacting the same way regardless of the type of pathogen or antigen.

Question 3

What are physical barriers in plants?

Answer 3

They are barriers that impede or prevent entry of pathogens.

-thick bark
-waxy cuticles of leaves
-formation of galls to prevent spread of infection
-presence of thorns and trichomes to deter insects and grazers
-closing of stomata to prevent pathogen invasion during carbon dioxide uptake

Question 4

what are chemical barriers in plants?

Answer 4

Barriers that inhibit pathogen growth or development and/ or destroy pathogens. Includes the production of harmful chemicals (eg toxins) and enzymes that disrupt pathogen function or development.

Question 5

what are physical barriers in animals?

Answer 5

barriers that prevent or impede entry of pathogens.

-skin (intact) and surfaces between external and internal environment
-mucous secretions and/or hairs in respiratory tract that trap organisms and cilia

Question 6

chemical barriers in animals?

Answer 6

barriers that act to inhibit the growth or development of pathogens and/or act to destroy pathogens

Question 7

examples of chemical barriers in animals?

Answer 7

• lysozome enzymes in tears and saliva
• acidic sweat that destroys pathogens growing on the surface of the body
• stomach acid
  -antibacterial compounds in ear wax
• antibacterial proteins in semen
• low PH in the vagina

Question 8

what are microbiological barriers?

Answer 8

non-pathogenic bacteria in body which can prevent growth or colonisation of pathogenic micro-organisms as they compete for space and resources