Non specific defence systems + the immune system Flashcards
State some of the non-specific defence systems of the human body against pathogens
the non-specific defence systems
of the human body against pathogens, including the:
skin
nose
trachea and bronchi
stomach
phagocytosis
State an example of specific responses of the body
Lymphocytes
What is the job of the non-specific defence system
The job of the non-specific defence system is to prevent pathogens from entering the human body
Explain how the skin works as a non specific defence system
The skin covers the body and acts as a barrier. Prevents bacteria and viruses from reaching the tissues beneath
Sometimes the skin is damaged and that could allow pathogens to enter the body. To stop this, the skin scabs over. -
If you damage or cut your kin, the barrier is broken bt your body restores it.
You bleed, and the platelets in your blood set up a chain of events to form a clot that dries into a scab. This forms a seal over the cut, stopping pathogens from getting in.
The skin produces antimicrobial secretions to destroy pathogenic bacteria
Healthy skin is covered with microorganisms that help keep you healthy and act as a barrier to the entry of pathogens
Explain how the nose works as a non specific defence system
The nose contains hairs and produces a sticky liquid called mucus
The hairs and the mucus trap particles in the air that may contain pathogens or irritate your lungs
Explain how the trachea and bronchi works as a non specific defence system
The trachea and the bronchi secrete mucus that traps the pathogens from the air.
The lining of the tubes is covered in cilia - tiny hair-like projections from the cells. The cilia beat to waft the mucus up to the back of the throat where it is swallowed
Explain how the stomach works as a non specific defence system
The stomach produces acid an this destroys the microorganisms in the mucus you swallow as well as the pathogens you take in through your mouth in your food and drink
State the job of the immune system
The immune system destroys pathogens and any toxins they produce
State the ways White blood cells help to defend against pathogens
White blood cells help to defend against pathogens by:
phagocytosis
antibody production
antitoxin production
State how phagocytosis protects you against disease
Some white blood cells (Phagocytes) ingest pathogens, digesting and destroying them so they cannot make you ill
Describe the process of phagocytosis
The white blood cell (the phagocyte) detects chemicals released from the pathogen and moves towards it
The white blood cell then ingests the pathogen,
The phagocyte uses enzymes to destroy the pathogens.
The white blood cell (the phagocyte) detects chemicals released from the pathogen and moves towards it.
When it reaches the pathogen, the phagocyte binds to it.
The phagocyte surrounds the pathogen and ingests the pathogen, taking it inside a vesicle known as a phagosome.
The phagocyte uses enzymes called lysozymes to destroy the pathogens.
State how producing antibodies protects you against disease
Some white blood cells (Lymphocytes) produce special chemicals called antibodies. The antibodies stick to the pathogens. This triggers the pathogens to be destroyed
What is an antibody
Antibodies are protein molecules produced by white blood cells
State some properties of antibodies
Properties of antibodies
Antibodies are extremely specific - you need a unique antibody for each type of pathogen.
When your white blood cells have produced antibodies once against a particular pathogen, they can be made very quickly if that pathogen gets into the body again, this stops you from getting the disease twice.
State how producing antitoxins protects you against disease
Some white blood cells produce antitoxins. These counteract (cancel out) the toxins released by pathogens. This is done by the antitoxins sticking to the toxin molecule and preventing them from damaging cells.
