Study Note: Overview of the Immune
System
1. Introduction to the Immune System
The immune system is divided into two main categories:
Innate Immune System: Provides immediate, generalized responses to
pathogens.
Specific Immune System: Involves specialized T and B cells that respond to
specific pathogens after a delay.
2. Components of the Immune System
A. Innate Immune System
Physical Barriers: Skin and mucosal surfaces act as the first line of defense
against pathogens.
Chemical Barriers: Include substances like hydrochloric acid in the stomach and
lysozyme in tears that destroy pathogens.
B. Initial Immune Response
1. Macrophages: Recognize and engulf pathogens through phagocytosis.
2. Dendritic Cells: Capture antigens and activate T and B cells.
3. Complement System: Activated by pathogens to enhance the immune response.
C. Inflammatory Response
Cytokines: Signaling proteins released by macrophages to recruit more immune
cells.
Inflammation: Involves increased blood flow, vascular permeability, and
recruitment of additional immune cells.
3. Specific Immune System
A. T and B Cells
T Cells: Recognize infected cells and can differentiate into helper and cytotoxic T
cells.
B Cells: Produce antibodies specific to pathogens.
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System
1. Introduction to the Immune System
The immune system is divided into two main categories:
Innate Immune System: Provides immediate, generalized responses to
pathogens.
Specific Immune System: Involves specialized T and B cells that respond to
specific pathogens after a delay.
2. Components of the Immune System
A. Innate Immune System
Physical Barriers: Skin and mucosal surfaces act as the first line of defense
against pathogens.
Chemical Barriers: Include substances like hydrochloric acid in the stomach and
lysozyme in tears that destroy pathogens.
B. Initial Immune Response
1. Macrophages: Recognize and engulf pathogens through phagocytosis.
2. Dendritic Cells: Capture antigens and activate T and B cells.
3. Complement System: Activated by pathogens to enhance the immune response.
C. Inflammatory Response
Cytokines: Signaling proteins released by macrophages to recruit more immune
cells.
Inflammation: Involves increased blood flow, vascular permeability, and
recruitment of additional immune cells.
3. Specific Immune System
A. T and B Cells
T Cells: Recognize infected cells and can differentiate into helper and cytotoxic T
cells.
B Cells: Produce antibodies specific to pathogens.
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