Chapter 43: The Immune System

Question 1

What are pathogens?

Answer 1

Disease-causing agents like bacteria, viruses etc.

Question 2

There are two layers of protection from pathogens. What are they?

Answer 2

Innate immune system

Adaptive immune system

Question 3

How does the innate immune system work?

Answer 3

Recognizes common pathogen tags and has a general response

Question 4

What are barrier defenses for innate immunity?

Answer 4

• skin
• mucus (thick fluid traps pathogens)
• fluids (saliva, sweat, tears)
  ^ creates unfavorable environment

Question 5

How does the cell recognize pathogens for innate immunity?

Answer 5

There’s something present (antigen) on the pathogen that’s not present on your other cells.

Question 6

What are 3 ways to kill a pathogen in innate immunity?

Answer 6

1) Interferons
- cells that signal other cells over for help
2) Enzymatic secretions
- these proteins/enzymes secrete products to attack the pathogen
3) Phagocytosis
- the cell creates a pocket to eat the dead pathogen

Question 7

How does the innate immunity work for a physical wound?

Answer 7

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

Question 8

How can a pathogen dodge the immune system in terms of receptors?

Answer 8

• 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.

Question 8

How can a pathogen dodge the immune system in terms of cellular response?

Answer 8

• 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
• phagocytosis:
  
  • cannot do phagocytosis if receptors do not touch pathogens

Question 9

How can a pathogen dodge the immune system in terms of inflammatory response?

Answer 9

It could stop cells from notifying each other to release secretory products

Question 10

In general, why might some pathogens surpass the immune system?

Answer 10

They multiply very quickly and the immune system doesn’t have time to catch them

Question 12

How does the adaptive immune system work?

Answer 12

Learns specific features on pathogens and has a specific response for them

Question 13

What are the two main cells of adaptive immunity and what are their differences?

Answer 13

B cells - good for fighting free floating pathogens

T cells - good for fighting pathogens that have affected the cells

Question 14

What is an antigen?

Answer 14

Specific feature (substance) recognized about a specific pathogen

Question 15

What are antigen receptors?

Answer 15

Receptors created by memory in order to attack the pathogen if it comes back

Question 16

What happens when the receptor of a B cell binds to the antigen of a pathogen?

Answer 16

• The other receptors on that B cell are released as antibodies to find other pathogens
• The antibodies bring all the pathogens together

Question 17

How does a T cell help an infected cell?

Answer 17

• 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

Question 18

How does adaptive immunity remember specific features of a pathogen?

Answer 18

• 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

Question 19

What happens to your cellular response the more and more you’re exposed to the same pathogen?

Answer 19

Your cellular response is much faster

Question 20

How do antibodies prevent further infections?

Answer 20

They neutralize the pathogen by blocking a virus’s ability to bind to a cell

Question 21

How does phagocytosis work?

Answer 21

• 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)

Question 22

How do vaccines work?

Answer 22

• 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

Question 23

Why don’t vaccines always work?

Answer 23

• 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

Question 24

What is an important component about our blood type?

Answer 24

Blood type A has A sugars
Blood type B has B sugars
Blood type AB has AB sugars
Blood type O has no sugars

Question 25

If you have blood type A, and you were injected with someone’s blood which is type B, what would happen?

Answer 25

• 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!

Question 26

Why are people with blood type AB considered universal acceptors?

Answer 26

They are able to accent any blood type because they do not have any antibodies that will attack A or B sugars

Question 27

What is autoimmune disease?

Answer 27

When you try to kill your own cells (because you’re allergic to yourself)