Immune System 1: Flashcards
What are the mucosal parts?
The mucosal bots of our body are the main entry points for pathogens. They include stuff like our respiratory system our glands and our urinary and intestinal tracts
What is the first layer of protection against pathogens
Our skin is the first thing of protection. Most pathogens cannot pass the skin, this is why the majority of pathogens will infect us via our mucus
Describe the four different mechanical barriers
Across our skin intestine lungs as well as eyes nose mouth, we have epithelium cells that prevent pathogens from crossing inside.
In the intestine, peristaltism helps remove the bacteria just by pushing them through the system.
In the lungs, a similar thing happens with the movement of the cilia pushing bacteria outside the bronchi.
Tears and cilia also play an important role in reducing infections
Describe a few chemical barriers protecting us against pathogens
Fatty acids on our skin
Acidic acid low ph
Digestive enzymes
Surfactant in our lungs
Enzymes in our tears and our saliva
Provide an example of the microbiological barrier that protects us against pathogens
One great example of this is the microbiome.
The diversity in the microbiote serves to teach our immune system how to react to different pathogens.
Why does a breach in microbiote can lead to infection
Because the perturbation of the normal flora can allow bacteria to easily access food that otherwise would be taken up by our normal bacteria. In addition our immune system is weakened
Give an example of how a breach in the mechanical barrier can lead to an infection
In terms of the skin, of reach in the epithelial layer makes us vulnerable to a cellulitis
In cystic fibrosis there is an issue with the cilia which makes it more difficult to move mucus outside of the lungs making it more likely for these patients to get an infection because the bacteria stays there.
Give an example of how a breach in the chemical barrier can lead to an infection
Let’s say that we have a patient that has terrible acid reflux.
If the patient is taking proton pump inhibitors they would increase the gastric ph which would favor the infections from Clostridioides difficile as well as salmonella. This is because the reduced stomach acidity increases the rate of survival of bacteria
Describe an example of how a breach in the microbiological barrier can lead to an infection
A patient that takes antibiotics could potentially perturbate her natural flora which could allow Clostridioides difficile to proliferate and cause an infection.
Another example are antibiotics that perturb the vaginal flora leading to fungal infections
What is the first attacker of the pathogen once the p[athogen has passed the first three layers of protection
The complement system
What is the main role of the complement system in the innate immune system?
The first role is the detection of a pathogen that leads to an activation cascade
Describe the three consequences of the activation of the complement system cascade
1 production of pro inflammatory cytokines
2 sticking of the complement proteins on the surface of the pathogen which lead to the lysis of the pathogen via the formation of a membrane attack complex
3 the proteins activated by the complement will be sticking to the surface of the pathogen favoring its phagocytosis (opsonisation)
What do the cytokines release by the complement system do?
Let’s say cause a vasodilation of the blood vessels increasing permeability which leads to the recruitment of other immune cells.
The cytokines released by the complement immune system are essentially a messenger for the cells in the near environment
Describe what are cytokines
Cytokines are a way of communication between different cells.
They can message for proliferation differentiation activation vasodilation molecule synthesis or even fever. For example some cytokines can travel to the brain and trigger an increase in temperature in the hypothalamus.
Cytokines can be autocrine paracrine or endocrine
Describe the membrane attack complex
The membrane attack complex is created from the complement system
What happens here is that the complements will stick to the surface of the pathogen and start creating small holes in the membrane
These holes essentially mean that the bacteria will die