Non-Specific Defence Systems

• The job of a non-specific defence system is to prevent pathogens from entering the human body.
• The skin forms a protective layer covering the body.
• The outer layer of the skin consist of dead cells and is difficult for pathogens to penetrate.
• The skin also produces an oily substance called sebum which can kill bacteria.
• Sometimes the skin is damaged and that could allow pathogens to enter the body. To stop this, the skin scabs over.
• The nose contains hair and mucus. These can trap pathogens before they enter the breathing system.
• The trachea and bronchi are covered with tiny hairs called cilia. Cilia are covered in mucus which can trap pathogens.
• The cilia now waft the mucus upwards towards the throat where it is swallowed into the stomach.
• There are lots of different pathogens that can be present on food. The stomach contains hydrochloric acid. This kills pathogens before they can make their way further down into the digestive system.