Defence Systems

Question 1

Job of non specific defence system

Answer 1

Prevent pathogens from entering the body

Question 2

How does body prevent disease

Answer 2

Skin
= outer layer contains dead cell which is hard for pathogens to penetrate
= produces sebum which kills bacteria
Nose
= contains hair and mucus
= trap pathogens
Lungs
= trachea and bronchi covered with cilia
= cilia covered in mucus to trap pathogens
Stomach
= contains hydrochloric acid
= kills pathogens before entering digestive system

Question 3

When does the non specific system not work

Answer 3

When skin is damaged
= pathogens can invade body and enter blood stream
= once inside body pathogens multiply and damage healthy tissue

Question 4

Functions of immune system

Answer 4

Destroy pathogens and any toxins they produce
Protects us incase the same type of pathogen invades again in the future

Question 5

Describe process of phagocytosis in the white blood cells

Answer 5

Ingest and destroy pathogens
= detects chemicals released from pathogen and moves towards it
= wbc then ingests pathogen
= wbc uses enzymes to destroy pathogens
= phagocytosis

Question 6

How do antibodies work

Answer 6

• wbc produces antibodies
• antibodies stick to pathogens
  = triggers pathogens to be destroyed

Question 7

Define an antibody

Answer 7

Protein molecules produced by white blood cells

Question 8

Key factors of antibodies

Answer 8

Extremely specific
Can remain in the blood for a long time
= can protect us incase we ever get infected again with the same pathogen

Question 9

How do white blood cells involve antitoxins

Answer 9

Wbc produce antitoxins
= stick to toxin molecules and prevent them from damaging cells

Question 10

Key roles of wbc

Answer 10

Release antitoxins
Produce antibodies
Ingest pathogens (phagocytosis)

Question 11

How does immune system fight diseases

Answer 11

• producing antibodies
= to destroy specific pathogens
• producing antitoxins
= to counteract toxins released by pathogens

Question 12

Reasons for formation of fossils

Answer 12

• conditions needed for decay are absent
• parts of the organism are replaced by other materials as they decay
• or other preserved traces of organisms, eg footprints, burrows and rootlet traces

Question 13

How does body become immune after vaccination

Answer 13

• dead pathogen injected
• stimulates lymphocytes to produce antibodies
• antibodies made quickly on re-infection