External body defences Flashcards
How does the ear protect against pathogens?
cerumen (ear wax) traps pathogens so that they can’t enter ear
What 2 protective barriers are in the mouth?
mucous membrane, saliva
How does saliva protect against pathogens?
Saliva contains many antimicrobial proteins
How does mucous membranes in mouth protect against pathogens?
Secreted mucus is sticky and traps infectious particles and dust
How does stomach acid protect against pathogens?
It is hydrochloric acid, pH is strong enough to kill pathogens
What is the pH of HCl in stomach?
1.0-2.5
How does vaginal secretion protect against pathogens?
Secretion is acidic, so inhibits pathogen and fungal growth
What agents make vaginal secretion acidic?
Lactobacilli produce lactic acid which maintains pH 4-4.5, also hydrogen peroxide
How does the anus protect against pathogens?
The mucous membrane traps pathogens
How does nasal cavity hair protect against pathogens
Hairs catch germs, fungus, spores that are inhaled
What 2 defences are in the nasal cavity?
Mucous membranes, nasal hairs
How does the urethra protect against pathogens?
resident immune cells and epithelial cells secrete cytokines and antimicrobial agents
How does skin protect against pathogens?
Skin forms an impervious barrier
What do tears contain?
Lyzozyme, lactoferrin, IgA, complement that inhibit bacterial growth in eyes
