Barriers Agaainst Infection Flashcards
How does layer of keratin and secreted wax help prevent bacteria
Layer of keratin and secreted wax help prevent bacteria because makes skin impermeable to microogranisms
How does skin surface being salty and acidic protect body
Skin surface being salty and acidic protects body by making it difficult for microorganisms to grow as they are not used to conditions
How does large numbers of microbes living on skin protect body
Large numbers of licrobes (skin flora) living on skin surface helps protect body by out competing harmful bacteria. Produce toxins which harm harmful bacteria
How does blood clotting protect body
Blood clotting helps protect body by sealing cuts and abrasions to stop microorganisms gaining access to wounds.
How does mouth limit entry of pathogens
Mouth limits entry of pathogens using:
Lysozyme in saliva (breaks down bacterial cell walls)
Hydrochloric acid in stomach <2pH
Gut flora- bacteria that aid digestion and outcompete pathogenic bacteria for nutrients/space
How does nose prevent entry of pathogens
Nose prevents entry of pathogens by:
Mucus secreted by goblet cells which traps microbes, mucus wafted up by ciliated epithelium, mucus swallows and microbes killed by stomach acid
Lysozyme in nasal secretions
How do eyes and ears prevent entry of pathogens
Eyes prevent entry with lysozyme in tears
Ears prevent entry with bactericidal wax
How does vagina prevent entry of pathogens
Vagina prevents entry of pathogens by acidic pH to prevent growth of bacteria.
Where are mucous membranes found and how do they protect against infection
Mucous membranes are found in airways and gut, protect body with mucus and cilia. Mucus (secreted by goblet cells) in trachea and bronchi, trap microbes and other particles; then beating cilia carry mucus up to throat where it is swallowed and destroyed by stomach acid.
How does stomach protect body
Stomach protects body with hydrochloric acid, has a pH less than 2.
How do gut flora protect body
Gut flora protect body by aiding digestive process, excluding pathogenic bacteria, competing with pathogens for food and space and producing lactic acid which kills pathogens.
Why do more bacteria grow in airways and gut
More bacteria grow in airways and gut because they lack keratin layer, surface is always moist, making it a more favourable environment for bacterial growth
What are barriers and why are they called barriers
Barriers are chemical or physical
Called barriers because they don’t recognise antigens, only prevent entry
