1B- The Host Response Flashcards
innate defenses
◦ Born with
◦ Develop and strengthen over time (hair, skin, mucus membranes)
◦ No prior exposure needed
acquired immunity
develops due to exposure of the host to an infectious agent
◦ Specific and has memory
non-specific defenses
Physiologic barriers (pH + temperature), Anatomic barriers, mechanical barriers, phagocytic barriers (macrophages/neutrophils), inflammatory barriers
Anatomic barriers
‣ Epithelial surfaces (skin and hair, mucosa, cilia in the respiratory tract)
‣ Skin, hair, hooves, nails, mucous membranes
‣ Cell turnover
‣ pH, Proteins/lipids in sweat/oils on skin, Normal flora, Body secretions, innate inflammatory response
Anatomic barriers - pH specific
acid in the stomach, bile in the small intestine; protects and prevents the attachement of pathogens
Anatomic barriers - upper resp tract specific
- Nasal hairs
- Cilia
- Mucus blanket
- Cough reflex
- Alveolar macrophages
Anatomic barriers - normal flora specific
occupy attachement sites; produce by-products
Anatomic barriers - body secretions specific
prevent pathogenic agents from attaching and flush them away • Urine • Mucous • Milk • Tears • Enzymes • Iron chelators • Anti-toxins
Anatomic barriers - innate inflammatory response specific
triggered by tissue damage
chemokine release triggers
attracts inflammatory cells to the site of injury
chemotaxis
attraction of inflammatory cells to the site of injury (by chemokines)
chemotaxis results
cause blood vessel to dilate and become “leaky” allowing white blood cells to escape from the blood vessels into the damaged tissue
phagocytic barriers
macrophages and neutrophils
inflammatory barriers
dilated leaking blood vessels allow delivery of inflammatory cells and proteins to the site of injury/infection
interferons
polypeptides produced and secreted by cells containing viruses
‣ Helps prevent spread by protecting other cells
