barriers to infection

Question 1

skin

Answer 1

keratin
blood clots
skin flora

Question 2

keratin

Answer 2

outer layer of skin
prevents entry of microorganisms to body

Question 3

blood clots

Answer 3

seal open wounds to prevent entry of pathogens via wound

Question 4

skin flora

Answer 4

highly adapted to conditions on the skin (salty sweat, urea, fatty acids) so outcompete any other microorganisms on surface
prevents colonisation from other bacteria

Question 5

mucuous membranes

Answer 5

mucus
cilia
lysozyme

Question 6

mucus

Answer 6

secreted by goblet cells in trachea and bronchi
traps microbes and other particles

Question 7

cilia

Answer 7

beat to carry the mucus up to the throat where it is swallowed

Question 8

lysozyme

Answer 8

in mouth, nasal, and eye secretions
contains digestive enzymes which breakdown cells of bacteria, causing it to burst

Question 9

stomach acid

Answer 9

in gastric juices secreted by gastric glands
pH of less than 2
optimal pH for digestive enzyme pepsin
kills most bacteria which enters stomach with food

Question 10

gut flora

Answer 10

small and large intestine
ideal conditions- warm, moist, plentiful food
aid digestive process
outcompete pathogenic bacteria for food and space
bacteria secrete chemicals which help defence against pathogens