Non-specific defences of the human body against pathogens | Exit Quiz | Oak National Academy

The human body has defences against pathogens. These include physical defences, ___ defences and microbial defences.

Answer explanation

An example of a chemical defence is the acid in the stomach which helps to destroy pathogens on any contaminated food we eat.

Match each type of defence to the correct example.

• chemical defence

• a scab forming to prevent infection

• microbial defence

• the microbiota

• physical defence

• eyes producing tears that contain enzymes to break down pathogens

Answer explanation

The body has a wide range of defences to help prevent infection; including physical, chemical and microbial defences.

The function of the ___ system is to protect us against pathogens.

Answer explanation

White blood cells are a major part of the immune system which is adapted to protect us against pathogens.

Two types of white blood cells are lymphocytes and ___.

Answer explanation

The function of phagocytes is to carry out the process of phagocytosis.

Put the steps in the correct order to explain how phagocytosis takes place.

• The pathogen is destroyed.

• Phagocytes are attracted to pathogens by chemical signals.

• The cytoplasm of the phagocyte changes shape and engulfs the pathogen.

• Enzymes digest the pathogen.

Answer explanation

Phagocytosis is a process that involves white blood cells, called phagocytes, which engulf and break down pathogens.

Why is phagocytosis described as a non-specific defence?

• The phagocytes will engulf any pathogen.

• The phagocytes will engulf all cells they encounter.

• The phagocytes only engulf one type of pathogen.

• The phagocytes will engulf white blood cells.

Answer explanation

The function of white blood cells is to respond to pathogens that get past the physical, chemical and microbial defences of our bodies. Phagocytosis is non-specific, as the phagocytes will engulf any pathogens.