Non-Specific Body Defences Flashcards
What is a pathogen?
A bacterium, virus or other organism that can cause disease.
Give an account on non specific immune responses?
- Can be physical or chemical
- Comprises of cells and mechanisms that defend humans against infection by pathogens.
- Recognise and respond to pathogens immediately
- Cannot give long lasting protective immunity
Name the 4 main functions of the non-specific immune system?
· Physical Barriers
· Production of secretions
· Inflammatory response
· Phagocytosis
What is a physical barrier?
closely packed epithelial cells in the inner linings of the digestive and respiratory systems.
Give an account on chemical secretion
- examples include: tears, saliva, mucus and stomach acid
- produced to trap or destroy invading pathogens.
What does the inflammatory response do involve?
Inflammation involves changes to protect the tissues that have become infected.
What do mast cells release during the inflammatory response?
Histamine
What does histamine do to the blood capillary?
histamine causes blood capillary to vasodilate and become more permeable.
During the inflammatory response what leaves the capillary? What do they do?
phagocytes and clotting elements leave capillary and accumulate near the infection site.
What do phagocytes do to bacteria and what is this process called?
Phagocytosis - phagocytes engulf and destroy bacteria.
What does the clotting factor do?
Clotting factors promotes the wound healing.
What do phagocytes release?
Cytokine (signal molecule)
What does Cytokine do?
Attracts more phagocytes to accumulate at the site of infection.
When pathogens are being engulfed, what fuse together to release digestive enzymes?
Lysosomes fuse with vesicle releasing digestive enzymes.
What is the result of pathogens being digested?
Products diffuse into cytoplasm for use (nutrients), or removed from cell as waste.
