1. - **Granulocytes**
1.1. - **Neutrophils**
1.1.1. - First responders to bacterial infections.
1.1.2. - **Functions**:
1.1.2.1. - Perform phagocytosis to engulf bacteria.
1.1.2.2. - Release enzymes like defensins and proteases.
1.1.2.3. - Drawn to infection sites by chemotaxis.
1.1.3. - **Processes**:
1.1.3.1. - Margination: Adherence to capillary walls.
1.1.3.2. - Diapedesis: Squeezing through endothelial gaps.
1.1.3.3. - Neutrophilia: Increase in neutrophils during infection.
1.1.4. - **Lifespan**: 6-7 hours in blood, 1-4 days in tissues.
1.2. - **Eosinophils**
1.2.1. - Combat parasites and moderate allergic responses.
1.2.2. - **Functions**:
1.2.2.1. - Release Major Basic Protein (MBP) and Eosinophil Cationic Protein (ECP), which are toxic to parasites.
1.2.2.2. - Respond to allergic reactions through chemotactic factors.
1.2.3. - **Mechanism**:
1.2.3.1. - Attach to parasite surfaces and release toxic enzymes.
1.2.4. - **Association**:
1.2.4.1. - Increase in parasitic infections (eosinophilia) and allergies.
1.3. - **Basophils**
1.3.1. - Trigger allergic reactions and inflammation.
1.3.2. - **Functions**:
1.3.2.1. - Release histamine to increase capillary permeability.
1.3.2.2. - Secrete heparin to prevent blood clotting.
1.3.2.3. - Bind to IgE to trigger degranulation.
1.3.3. - **Role**: Involved in early allergic responses.
2. - **Lymphocytes**
2.1. - **T-Cells**
2.1.1. - **Helper T-Cells (CD4+)**
2.1.1.1. - Direct immune responses.
2.1.1.2. - Secrete cytokines like IL-2, IL-4, and IL-6.
2.1.1.3. - **Types**:
2.1.1.3.1. - TH1: Focus on cellular immunity (e.g., killing infected cells).
2.1.1.3.2. - TH2: Assist B-cells in producing antibodies.
2.1.2. - **Cytotoxic T-Cells (CD8+)**
2.1.2.1. - **Mechanisms**:
2.1.2.1.1. - Perforin: Punches holes in target cell membranes.
2.1.2.1.2. - Granzymes: Induce apoptosis.
2.1.3. - **Regulatory T-Cells**
2.1.3.1. - Prevent immune system overactivation.
2.1.4. - **Memory T-Cells**
2.1.4.1. - Quickly respond to previously encountered antigens.
2.2. - **B-Cells**
2.2.1. - Produce antibodies for humoral immunity.
2.2.2. - **Functions**:
2.2.2.1. - Attack infected or abnormal cells.
2.2.2.2. - Differentiate into plasma cells to secrete antibodies.
2.2.2.3. - Create memory cells for faster future responses.
2.2.3. - **Antibodies**:
2.2.3.1. - IgG: Most abundant; crosses placenta for neonatal immunity.
2.2.3.2. - IgA: Found in mucosal areas like saliva and tears.
2.2.3.3. - IgM: First antibody to respond; triggers complement activation.
2.2.3.4. - IgE: Involved in allergic reactions.
2.2.3.5. - IgD: Aids in B-cell activation.
2.3. - **Natural Killer (NK) Cells**
2.3.1. - Target virus-infected and cancerous cells without prior activation.
2.3.2. - Release perforin and granzymes to destroy targets.
3. - **Agranulocytes**
3.1. - **Monocytes**
3.1.1. - Transform into macrophages in tissues.
3.1.2. - **Functions**:
3.1.2.1. - Phagocytose debris, pathogens, and old cells.
3.1.2.2. - Present antigens to T-cells for immune activation.
3.1.3. - **Specialized Forms**:
3.1.3.1. - Kupffer Cells (Liver).
3.1.3.2. - Alveolar Macrophages (Lungs).
3.1.3.3. - Microglia (Brain).
3.2. - **Macrophages**
3.2.1. - **Functions**:
3.2.1.1. - Clean up after infections and injuries.
3.2.1.2. - Secrete cytokines like IL-1, IL-6, and TNF-α to recruit immune cells.
3.2.1.3. - Present antigens to T-cells.
4. - **Phagocytosis**
4.1. - **Steps**:
4.1.1. 1. Recognition: Invaders are marked with C3b (complement) or antibodies (IgG/IgM).
4.1.2. 2. Engulfment: Pathogens are engulfed into a phagosome.
4.1.3. 3. Destruction:
4.1.3.1. - Hydrolytic enzymes.
4.1.3.2. - Reactive Oxygen Species (e.g., H2O2).
4.1.3.3. - Myeloperoxidase (MPO): Produces hypochlorous acid to kill microbes.
5. - **Inflammation**
5.1. - **Phases**:
5.1.1. - **Initiation**:
5.1.1.1. - Chemicals like histamine and prostaglandins increase blood flow.
5.1.1.2. - Capillaries become leaky to allow immune cells entry.
5.1.2. - **Amplification**:
5.1.2.1. - Cytokines like IL-1 and TNF-α recruit neutrophils and monocytes.
5.1.3. - **Resolution**:
5.1.3.1. - Macrophages clean up debris; tissue heals.
5.2. - **Signs**:
5.2.1. - Rubor (Redness).
5.2.2. - Calor (Heat).
5.2.3. - Tumor (Swelling).
5.2.4. - Dolor (Pain).
5.2.5. - Functio Laesa (Loss of Function).
6. - **Types of Immunity**
6.1. - **Innate Immunity (Always Present)**
6.1.1. - **Components**:
6.1.1.1. - Skin, mucous membranes, phagocytes, NK cells.
6.1.2. - **Examples**:
6.1.2.1. - Lysozymes: Break bacterial cell walls.
6.1.2.2. - Stomach acid: Destroys ingested pathogens.
6.2. - **Adaptive Immunity (Learned Response)**
6.2.1. - **Components**:
6.2.1.1. - T-cells, B-cells, and antibodies.
6.2.2. - **Features**:
6.2.2.1. - Specificity: Targets specific antigens.
6.2.2.2. - Memory: Faster response upon re-exposure.
7. - **Antibodies**
7.1. - **Functions**:
7.1.1. 1. Neutralization: Block invaders from binding to cells.
7.1.2. 2. Agglutination: Clump pathogens for easier removal.
7.1.3. 3. Complement Activation: Trigger complement proteins to destroy invaders