Lecture 8: Innate Barriers Flashcards
What is the first barrier that comes with innate immunity?
Epithelial cells joined by tight junctions
Where is this first barrier (epithelium found)
In the skin, GI tract, respiratory tract and genitourinary tract
How can you know that epithelium and skin barriers are so important?
In severe burn victims the most common complications is sepsis (infection)
What makes the skin such a good barrier?
Its sealed with tight junctions
What else does your skin possess to keep pathogens out?
- Watertight lipid layer, prevents some bacteria
- sloughing of dead skin cells brushes off lots of bacteria and viruses and what not
What are cilia
Active, hair like structures on the surface of the airway epithelium
What do cilia do?
Sweep particles and mucus up and out of airway
How can we tell cilia work for preventing infection?
Smoking decreases cilia size and smokers are more likely to get influenza
What is mucus composed of?
Glycoprotein and water, very viscus
How does mucus protect the epithelium?
Protects epithelium from pathogens and digestive and antimicrobial molecules, traps things
What is a mucus dysfunction known as?
Cystic fibrosis
In addition to barriers how are immunological barriers reinforced?
- chemical (acid)
- enzymatic (lysosome)
- molecular (defensives, IgA)
What are chemical barriers?
- stomach acid is slightly acidic
- skin slightly acidic
- salts in sweat make it hypertonic
- intestine, bile is alkaline
What are enzymatic barriers?
lysozyme is present in;
- tears
- saliva
- milk
- GI mucus
What is lysozyme?
Catalyzes the breakdown of bacterial cell walls
