physical and chemical barriers

Question 1

Skin

Answer 1

epidermis = dead cells, keratin and phagocytic immune cells. top layer thinnish and contains dendritic cells (innate immune cells)
dermis = thick layer of connective tissue, collagen and blood vessels and phagocytic immune cells .

Question 2

antimicrobial peptides

Answer 2

chemical defences of the skin
active against bacteria, fungi and viruses
work by forming a pore in microbial membranes so microbes loose nutrients and essential ions - kills and trap microbes

Question 3

Lysozome

Answer 3

chemical defence of the skin

enzyme that breaks down bacterial cell walls comes out of the sweat glands

Question 4

Sebum

Answer 4

chemical defence of the skin
low pH- prevents microbial colonisation
oily secretion that gives acidic pH

Question 5

Salt

Answer 5

chemical defence of the skin

creates a hypotonic environment that dehydrates pathogens it sucks the water out of them

Question 6

Mucosal membranes

Answer 6

1-2 layers, mucus and cells 
epithelium= tightly packed live cells, constantly renewed, mucous producing the goblet cells 
top layer is alive. 
eyes - ocular 
respiratory tract
gastrointestinal
urogenital/ rectal
line parts of the body that lead to the outside and are exposed to air.

Question 7

the mucosiliary escalator

Answer 7

Cilia beat in time and move mucus to the pharynx so we can cough it up any pathogens or dust from the respiratory tract.
cilia come from the columnar cells
goblet cells don’t have cilia

Question 8

gastrointestinal tract

Answer 8

stomach very low pH (1-3)
gall bladder - bile 
intestine - digestive enzymes 
mucus - traps microbes and enzymes break them down 
defensins

Question 9

tears as defence for the eye

Answer 9

flushing action - flush away the pathogens/ microbes
lysozyme
drainage - swallow

Question 10

urogenital tract

Answer 10

urine flow
lysozyme - break down bacterial cell walls
low pH
high osmolarity- has a lot of solute particles in the urine that prevents microbial growth.

Question 11

How can physical and chemical barrier be breached

Answer 11

respiratory mucosa - influenza
IV drug use 
gut mucosa - salmonella 
animal bites - rabies 
mosquito bites - malaria 
gut and burns - tetanus
penetration of the skin