These are agents that cause disease, infect a wide range of animals (including humans)
Function of immune system
recognize foreign bodies and responds with the production of immune cells and proteins
Get activated when there is an infection
active immediately upon infection. Present before any exposure to pathogens and is effective from the time of birth.
develops after exposure to agents such as microbes, toxins and other foreign substances
Where is the innate system found?
Animals and plants
In vertebrates, innate immunity is a first response to infections and also serves as the foundation of adaptive immunity
Innate Immunity in invertebrates
exoskeleton made from chitin forms the barrier to pathogens
enzyme that breaks down bacterial cell walls
circulate within hemo-lymph and carry out phagocytes; the ingestion and digestion of foreign substances including bacteria
How does the immune system recognizes bacteria and fungi?
By the structures on their walls.
How does the immune system react to different classes of pathogens?
The Innate immune responses are different for different classes of pathogens.
What are other additional defenses unique to vertebrates?
1. natural killer cells
3. inflammatory response
Barrier Defenses Example
Skin doesn't allow bacteria to come inside the body
Barrier Defenses include
skin and mucous of the respiratory, urinary and reproductive tracts.
trap and allow the removal of microbes
Body fluids hostile to microbes
saliva, mucus, and tears
What prevents growth of bacteria in skin and digestive system?
recognize groups of pathogens using toll-like receptors (TLR's)
2 types of phagocytic cells in mammals
engulf and destroy pathogens
found throughout the body
stimulate development of adaptive immunity
discharge destructive enzymes
Natural Killer Cells
detect abnormal cells and release chemicals leading to cell death
Peptides and proteins
attack pathogens or impeding their reproduction
provide innate defenses, interfering with viruses and helping active macrophages
causes lysis of invading cells and helps trigger inflamation
brought about by molecules released upon injury of infection
triggers blood vessels to dilate and become more permeable
chemical signals that enhance the immune system
condition caused by an overwhelming inflammatory response
Pathogens avoiding destruction
modify surfaces to prevent recognition or by resisting breakdown following phagocytosis
Receptors provide pathogen-specific recognition
mature in the thymus
mature in the bone marrow
substances that can elicit a response from a B or T cells
small accessible part of an antigen that binds to an antigen receptor
What are B nd T cells specialized?
to recognize a specific type of molecule