Flashcards in Chapter 43: The Immune System Deck (27)
What are pathogens?
Disease-causing agents like bacteria, viruses etc.
There are two layers of protection from pathogens. What are they?
Innate immune system
Adaptive immune system
How does the innate immune system work?
Recognizes common pathogen tags and has a general response
What are barrier defenses for innate immunity?
- mucus (thick fluid traps pathogens)
- fluids (saliva, sweat, tears)
^ creates unfavorable environment
How does the cell recognize pathogens for innate immunity?
There's something present (antigen) on the pathogen that's not present on your other cells.
What are 3 ways to kill a pathogen in innate immunity?
- cells that signal other cells over for help
2) Enzymatic secretions
- these proteins/enzymes secrete products to attack the pathogen
- the cell creates a pocket to eat the dead pathogen
How does the innate immunity work for a physical wound?
1) Macrophage (acting as an interferon) will call over other cells for help
2) The macrophage and other cells will release secretory products to attack the pathogens
3) Phagocytosis occurs
How can a pathogen dodge the immune system in terms of receptors?
- pathogens can secrete inhibitors to block/bind to the receptors
- pathogens can make a camouflage membrane to disguise itself
^these prevent the pathogen from binding to the receptor. As long as it avoids it, it doesn't do transduction or cellular response and it can invade the immune system.
How can a pathogen dodge the immune system in terms of cellular response?
- enzymatic secretions:
- pathogen could have its own receptors to catch the secretory products so that the cell is not notified
- pathogen could send out its own competitor inhibitors to bind to the receptors of other enzymes
- cannot do phagocytosis if receptors do not touch pathogens
How can a pathogen dodge the immune system in terms of inflammatory response?
It could stop cells from notifying each other to release secretory products
In general, why might some pathogens surpass the immune system?
They multiply very quickly and the immune system doesn't have time to catch them
How does the adaptive immune system work?
Learns specific features on pathogens and has a specific response for them
What are the two main cells of adaptive immunity and what are their differences?
B cells - good for fighting free floating pathogens
T cells - good for fighting pathogens that have affected the cells
What is an antigen?
Specific feature (substance) recognized about a specific pathogen
What are antigen receptors?
Receptors created by memory in order to attack the pathogen if it comes back
What happens when the receptor of a B cell binds to the antigen of a pathogen?
- The other receptors on that B cell are released as antibodies to find other pathogens
- The antibodies bring all the pathogens together
How does a T cell help an infected cell?
- The cell breaks up the antigens
- An MHC molecule displays an antigen fragment in the outside of the cell
- The T cell identifies it and its receptor binds to the antigen
--> the T cell will then signal for other cells to come over and help kill it
How does adaptive immunity remember specific features of a pathogen?
- The B cells will create antigen receptors after seeing a specific pathogen
- If it sees this pathogen again (antigens binding to its receptors, it will multiply and produce many memory cells with the same antigen receptors
- When the same pathogen comes back, the memory cells will be ready for them
What happens to your cellular response the more and more you're exposed to the same pathogen?
Your cellular response is much faster
How do antibodies prevent further infections?
They neutralize the pathogen by blocking a virus's ability to bind to a cell
How does phagocytosis work?
- Compliment proteins insert pores (proteins) into the membrane which create a hole for water and ions to flow in.
- The cell gets bigger and bigger until it bursts (lyses)
How do vaccines work?
- they take advantage of your adaptive immune system
- they carry antigens of the actual disease and expose your cells to them so that your cells can make antigen receptors and remember what the disease looks like
- this will increase your response time if you were to actually exposed to a disease
Why don't vaccines always work?
- vaccine was made last year, this year the disease has different properties
- sometimes not enough antigens are injected and your cells don't make any antigen receptors
What is an important component about our blood type?
Blood type A has A sugars
Blood type B has B sugars
Blood type AB has AB sugars
Blood type O has no sugars
If you have blood type A, and you were injected with someone's blood which is type B, what would happen?
- if you're blood type A, you have antibodies against B sugars
- your antibodies will attack these sugars and your cells will kill the B red blood cells
- therefore, the blood transfusion was ineffective
- this could even cause a blood clot!
Why are people with blood type AB considered universal acceptors?
They are able to accent any blood type because they do not have any antibodies that will attack A or B sugars