lecture 1

Question 1

what is variolation?

Answer 1

= exposure of an individual to the contents of dried smallpox pastures from an infected person

Question 2

how does the skin act as a barrier, physically, physiologically and subaceouusly?

Answer 2

Physically
= tightly packed keratinised cells

Physiologically
= low pH, low O2 tension

Subaceous glands
= secretes hydrophobic, lyzozymes, ammonia and anti-microbial peptides

Question 3

what does the mucus line?

Answer 3

= all the surfaces that come into contact with the external environment;

• respiratory
• GI
• urogenital

Question 4

describe how the mucus acts as a phycialy, secretory IgA, enzyme and cilia barrier?

Answer 4

Physically
= physically traps bacteria

cillia
= clears the trapped bacteria away, with the help of coughing and sneezing

enzymes
= lyzozymes, defensives, anti-microbial peptides all kill pathogens
& lactoferrin starves the bacteria

secretory IgA
= prevents bacteria from penetrating the epithelial surface

Question 5

how does commensal bacteria act as a barrier to infection?

Answer 5

= competes with pathogen for scarce resources

It;

• reduces the pH in large bowel
• synthesises Vit K/B12
• competes for essential nutrients