Innate Immune Defenses Flashcards
What is innate immunity?
Innate immunity is a nonspecific defense present at birth that works against a wide range of pathogens.
How does innate immunity differ from adaptive immunity?
Innate immunity is nonspecific, fast, and always active, while adaptive immunity is specific and slower to activate.
What are the three main types of innate immune defenses?
Physical defenses, chemical defenses, and cellular defenses.
What must a pathogen do to cause disease?
Gain access, attach to host cells, and evade immune defenses long enough to cause harm.
What are the first and second lines of defense in the immune system?
The first line includes physical and chemical barriers; the second includes protective cells and bloodborne chemicals.
Which immune line does innate immunity include?
The first and second lines of defense.
What structures make up physical defenses?
Skin, mucous membranes, endothelia, mechanical barriers, and the microbiome.
What are chemical defenses?
Specific chemicals in secretions like sweat, saliva, and mucus that inhibit or kill pathogens, cytokines, and inflammatory-eliciting mediators
What are cellular defenses?
Leukocytes (white blood cells) that destroy pathogens and trigger inflammation.
Why is the microbiome considered a defense mechanism?
It competes with pathogens for nutrients and space, preventing their growth.
What are the two layers of the skin?
Epidermis and dermis.
How does the epidermis protect against pathogens?
Through tightly packed cells and shedding of dead cells that remove microbes.
What role do dendritic cells in the epidermis play?
They phagocytize pathogens.
What is the mucociliary escalator?
A mechanism in the respiratory tract where mucus traps pathogens and cilia move them out.
What are goblet cells?
Cells that secrete mucus to trap pathogens.
What do ciliated columnar cells do?
Propel mucus and trapped pathogens away from the lungs.
Name a mechanical barrier in the body.
Blinking, flow of urine, or eyelashes.
What is the blood-brain barrier?
A tightly packed endothelial barrier that prevents pathogens from entering the CNS.
How do members of the microbiome prevent pathogen growth?
By consuming nutrients and blocking attachment to host cells.
What part of the skin inhibits pathogen growth by lowering pH?
Sebum.
What does sweat contain that helps prevent infections?
Salt and lysozyme.
How does lysozyme kill bacteria?
It destroys bacterial cell walls.
What is the pH of gastric juice and how does it help?
pH 2; it kills most pathogens.
What does lactate production by vaginal flora do?
Lowers pH and prevents pathogen growth.
