CB5F Physical and chemical barriers

Question 1

Give some examples of the body physical defense system (3)

Answer 1

Skin - protective barrier
Blood clotting - platelets seal wounds
Respiratory tract - mucus traps pathogens

Question 2

Give some examples of the body’s chemical defence system

Answer 2

Tears - contain lysozyme which digests bacterial cell walls killing bacteria and protecting eye

Hydrochloric acid in stomach - acidic pH kills pathogens that are swallowed

Question 3

Describe chlaymidia

Answer 3

Spread through sexual contact

Can result in infertility