Non - specific response

Question 1

What is the first line of defence?

Answer 1

Preventing entry:
- skin = many layers to limit entry, waxy oils contain toxic fatty acids
- tears, urine, saliva = contain lysozymes (enzymes that hydrolyse some proteins on the pathogens)
- ears = sticky wax
- stomach = hydrochloric acid
- epithelial cells indigestive, respiratory and reproductive systems = secrete mucus

Question 2

What are phagocytes?

Answer 2

a macrophage/type of white blood cell that ingests and digests pathogens (carries out phagocytosis)

Question 3

Where are phagocytes found?

Answer 3

in the blood and the tissues

Question 4

How do phagoctyes reach the area where an immune response was triggered?

Answer 4

• histamines are released and cause the small arteries leading to the infected tissue to dilate, allowing more blood to flow to the area and therefore more phagocytes
• phagocytes can leave the blood via small pores in the walls of the capillaries

Question 5

What is the process of phagocytosis?

Answer 5

1.) a phagocyte recognises the foreign antigens on a pathogen and move towards it by positive chemotaxis due to the toxins released by the pathogens
2.) phagocytes have many receptor binding points on the surface which will attach to antigens on the pathogen
3.) the ohagocytes changes shape and the cytoplasm of the phagocyte moves around th epathogen, engulfing it by endocytosis- invagination of plama cell membrane to form a phagosome (a membran ebound vesicle containing the pathogen)
4.) a lysosome withing the phagocyte will fuse to the phagosome and will release lysozymes (and lytic enzyme which hydrolyses the pathogen and so destroys it)
5.) the pathogen is digested (excreted) or used by phagocyte (soluble products absorbed)
6.) the phagocyte presents the antigens of the invading pathogen on its surface to stimulate the next immune respons