Defence against pathogens Flashcards
Immune system
If a pathogen enters our body due to failure of non specific defence system:
It destroys pathogens + toxins
Protects us if same type of pathogen enters again
What makes up the immune system?
White blood cells that travel in the blood
How do white blood cells respond to an infection
White blood cells:
Engulf it (phagocytosis) + destroy
Release antibodies
Releases antitoxins
How does phagocytosis work?
WBC detects chemicals released from pathogen and goes to it
INGESTS the pathogen
Uses enzymes to destroy them
What white blood cells name engulf the pathogen?
Phagocytes
What are antibodies and what are they made of?
Protein molecules
Represented by the Y shape
How do antibodies work?
Released by WBCs
Stick to the pathogen
Triggers pathogens to be destroyed
What’s special about antibodies?
They are very specific to each pathogen
Ie the antibodies are designed for one specific pathogen ONLY
How long do antibodies stay in the blood for?
A long time
How do antibodies protect us from future possible infections
If you get infected by pathogen,
The WBCs make specific antibodies against this pathogen
Which after the infection is gone still remain in the blood
So if that pathogen enters again, the pre existing antibodies will destroy the pathogen immediately
What are antitoxins and how do they work?
Chemicals produced by WBCs (not antibodies!!)
That stick to toxins produced by bacteria
Prevents the antitoxins from damaging cells and making us unwell
What is the name of the white blood cell that releases antibodies and antitoxins?
Lymphocytes
What do vaccines contain
Dead or inactive forms of the pathogen that we are being vaccinated against
Do vaccines cause the disease in patient?
No because the pathogens are DEAD or INACTIVE
How do vaccines work?
Enter the dead/inactive pathogen
Stimulates WBCs to release antibodies against it
But these WBCs divide by mitosis = copies of itself
That stay in the body for decades
So if the ALIVE version of the pathogen enters
These WBCs release the specific antibody much quicker = no infection