Immune System:
- All the times we are surrounded by microbes.
Types of Immune System Defense Mechanisms:
Non-Specific Defense Mechanisms (Innate Immunity)
o Innate Immune System: cells and proteins are always there to fight infection.
Triggered by a wide range of threats
First line of defense in the body always ready and prepared to defend
Defense at body surfaces (skin)
Phagocytosis (leukocytes)
Natural antimicrobial substances (Saliva, lysozymes, HCl),
tears, and cilia.
Second line of defense against invasion
Inflammatory response
Specific Defense Mechanisms (Adaptive Immunity)
o Adaptive Immune System: comes into action against pathogens that are able to
overcome the innate immune system
Directed against antigen (antigen-specific)
T & B cells: recognize antigens
Bacteria
Viruses
Parasites
Memory
The Inflammatory Response:
Causes:
Microbes
Physical changes (mechanical injury, heat)
Chemical agents
Microbial toxins
Organic poisons
Inorganic agents (acid)
, Signs:
Redness
Heat
Pain
Swelling
Steps for inflammatory response:
1. Mast cells release histamine: vasodilation and increase blood flow
2. Macrophages (monocytes) and neutrophils: engulf pathogens
3. Blood clotting prevent blood loss
4. Excess fluid in the injured area presses on nerve endings which then release
“bradykinin” causing pain
Acute Inflammatory Response: is beneficial as it removes harmful agents and allows
for healing (high Neutrophils and Monocytes)
Chronic Inflammation: high lymphocytes
Specific Defense Mechanisms (Adaptive Immunity):
- Take place when a nonspecific response fails to overcome the infection
- The immune response is directed against only one antigen
- All the times we are surrounded by microbes.
Types of Immune System Defense Mechanisms:
Non-Specific Defense Mechanisms (Innate Immunity)
o Innate Immune System: cells and proteins are always there to fight infection.
Triggered by a wide range of threats
First line of defense in the body always ready and prepared to defend
Defense at body surfaces (skin)
Phagocytosis (leukocytes)
Natural antimicrobial substances (Saliva, lysozymes, HCl),
tears, and cilia.
Second line of defense against invasion
Inflammatory response
Specific Defense Mechanisms (Adaptive Immunity)
o Adaptive Immune System: comes into action against pathogens that are able to
overcome the innate immune system
Directed against antigen (antigen-specific)
T & B cells: recognize antigens
Bacteria
Viruses
Parasites
Memory
The Inflammatory Response:
Causes:
Microbes
Physical changes (mechanical injury, heat)
Chemical agents
Microbial toxins
Organic poisons
Inorganic agents (acid)
, Signs:
Redness
Heat
Pain
Swelling
Steps for inflammatory response:
1. Mast cells release histamine: vasodilation and increase blood flow
2. Macrophages (monocytes) and neutrophils: engulf pathogens
3. Blood clotting prevent blood loss
4. Excess fluid in the injured area presses on nerve endings which then release
“bradykinin” causing pain
Acute Inflammatory Response: is beneficial as it removes harmful agents and allows
for healing (high Neutrophils and Monocytes)
Chronic Inflammation: high lymphocytes
Specific Defense Mechanisms (Adaptive Immunity):
- Take place when a nonspecific response fails to overcome the infection
- The immune response is directed against only one antigen
