SB5i Physical and chemical barriers

Question 1

What do physical barriers do?

Answer 1

make it difficult for pathogens to enter the body.

Question 2

What do chemical barriers do?

Answer 2

destroy or inactivate pathogens on the outside or inside the body.

Question 3

Physical barriers and how they work (3) humans

Answer 3

.Skin (pathogens struggle to get through the layers of skin and enter our body)​

.Ciliated cells (move mucus and the trapped pathogens away from the lungs, either out of the mouth or into the digestive system)​

.Mucus (sticky substance that traps pathogens and dust entering the body)

Question 4

Chemical barriers and how they work (2)

Answer 4

.Lysozymes (secreted by glands, in tears, in mucus and in saliva, killing bacteria by breaking down their cell walls)​

.Hydrochloric acid (kills the majority of pathogens that enter our body on food as the acid makes our stomach have a pH of 2)

Question 5

What are STIs?

Answer 5

sexually transmitted infections that overcome natural barries in the human reproductive system

Question 6

How are STIs spread?

Answer 6

.by contact with sexual fluids
.can also be passed between a pregnant mother and her baby

Question 7

How can STIs be prevented?

Answer 7

.screening i used to identify people with STIs so they can be treated