defensive barriers Flashcards
what are the 4 main epithelial surfaces
- Skin
- Respiratory tract
- Alimentary tract
- Urogenital tract
routes of infections - horizontal transmission (4)
- Direct contact (e.g. greasy pig disease)
- Physical interactions
- Aerosol (e.g. kennel cough)
- Inhalation of pathogens
- Oro-faecal
- Contaminated food or water
- Vector transmission
Pathogens uses an arthropod host to spread from animal to animal when it bites
routes of infection - vertical transmission
- Transplacental transmission
- Pathogens crosses the placental barrier to infect the fetus
defensive barriers (5)
- Physical barrier
- Skin
- Physiological barrier
- Mucous membranes
- Biochemical barriers
- Gastric acid
- Chemical barriers
- Lysozyme
- Cellular
- macrophages
function of skin flora
Create competition for space in skin to outcompete spaces for pathogens
3 types of cells for protection as physical barrier
Keratinocytes: replicate to generate stratified squamous keratinized epithelium
Melanocytes: protection from UV damage
Langerhans cells : capturing and processing microbes, then Langerhans cells travel to lymph nodes and activate white blood cells
function of keratinocytes
Keratinocytes: replicate to generate stratified squamous keratinized epithelium
Keratinocytes trigger inflammation -
- Produces cytokines (immunological hormones)
- Produce chemokines (cell migration factors)
function of melanocytes
protection from UV damage
function of langerhans cells
Langerhans cells : capturing and processing microbes, then Langerhans cells travel to lymph nodes and activate white blood cells
properties of sebum
-water repellent
- Contains fatty acids
- Anti-microbial components
what are the 3 divisions of the respiratory system
- conductive system
- transitional system
- gas exchange system
what do each of the 3 divisions of respiratory system consists of
Respiratory system as a defensive barrier
- Conductive system ○ Nasal cavity ○ Pharynx ○ Larynx ○ Trachea ○ Bronchi - Transitional system ○ Bronchioles - Gas exchange system ○ Alveoli
what are the oral and oesophagus defenses
- Oral cavity and oesophagus
- Stratified squamous epithelium provides a physical barrier
- Lysozyme in saliva acts as a biochemical barrier
what are the stomach defences
- Stomach
- HCl acid sterilize food
- Pepsin aids in digestion
- Mucous to protect epithelium
- Regulatory peptides
what are the small intestine defences
- Cryptidins
- It is toxic to bacteria produced by Paneth cells
