Page 1 of 53
MED SURG EXAM 3 - IMMUNE RESPONSE AND
INFECTION CONTROL NURSING COMPREHENSIVE 2026
QUESTIONS EXAM LATEST VERSION SOLVED QUESTIONS
& ANSWERS VERIFIED 100 %
Immune Response and Infection Control
what is an infection?
–Invasion and multiplication of harmful microorganisms (pathogens) in body
tissues
-we have organisms that are not self all throughout body (skin+gut). In some cases it
helps the body, normal flora is not invasive or bad. (not made up of own bodies
genetic material and cells but body tolerates them since they are helpful and not
harmful)
-pathogen when enter the body create infectious process that involves inflammation.
non self that multiplies and creates infection.
What is the inflammatory response?
–The body’s nonspecific (innate immune system) defense mechanism to
infection or injury
-bodies response to tissue damage due to the infection. tissue damage brings on the
inflammatory response. it involves vasodilation, capillary permeability = warmth,
swelling, redness, pain
for a immune response to be initiated what must happen?
-for an immune repsonse to occur, the foreign antigen must be recognized as non
self on presentation by APCs via the MHC molecule on its surface
🧠 What Are APCs?
APC = Antigen-Presenting Cell
, Page 2 of 53
Special immune cells that detect, “eat,” and show pieces of germs (antigens) to
other immune cells (like T cells). T cells are the cells in charge of differentiating
between self and non self when APC shows piece of antigen on MHC surface
Their job: start the immune response by telling T cells, “Here’s the invader—go
attack!”
🔹 Main Types of APCs
Macrophages – big eaters that engulf and digest bacteria and dead cells.
Dendritic cells – the best APCs; found in tissues that contact the outside (skin,
lungs, GI tract).
B cells – can also act as APCs when they bind their specific antigen through their B
cell receptor (BCR).
🍽️ How APCs “Eat” and Display Antigens
APCs engulf the pathogen (through phagocytosis or endocytosis).
Inside the cell, the pathogen is broken into tiny pieces (antigens).
The APC then attaches these pieces to a special surface protein called MHC
II (Major Histocompatibility Complex class II).
The MHC II + antigen complex is then displayed on the APC’s surface — like
holding up a “wanted poster” of the invader.
⚡️ How This Mounts an Immune Response
A Helper T cell (CD4+) comes by and recognizes the antigen on the APC’s MHC
II.
If it’s a foreign antigen (non-self), the Helper T cell activates.
The Helper T cell then releases cytokines (chemical messages) that:
Activate B cells → make antibodies
Activate Cytotoxic T cells → kill infected cells
Recruit macrophages → increase phagocytosis
What is the difference between Infection and Inflammation?
–Infection = the cause (pathogen present)
–Inflammation = the body’s response (redness, swelling, heat, pain)
*can have infection that causes inflammation (bodies response to infection) and can
have inflammation from other things
*can have infection that causes inflammation, can also have inflammation with any
sort of tissue damage (sprain ankle or cut)
, Page 3 of 53
*can you have infection without inflammation? HIV, anytime the immune system is
severly immunocompromised due to HIV/AIDS, drugs, steroids.
Can you have inflammation without infection?
-Yes: Inflammation can occur without infection (e.g., sprain)
Can you have infection without inflammation?
–Infection almost always triggers inflammation
**can you have infection w/o inflammation? HIV, drugs, meds (anything that
suppresses the immune system). if your immune system is suppressed or not
responding normally then you can infection w/o the bodies response of
inflammation. this occurs in pt that have supressed immune system or are
immunocompromised (HIV/ADIS, drugs, steroids)
What are the two main parts of the immune system?
-innate (natural) immunity, nonspecific --> first responders
-acquired (adaptive) immunity (specific) --> specialized defenders
what is innate immunity (also known as natural or nonspecific immunity)? how
many lines of defense are in innate immunity?
-This is the type of immunity we are born with, and it doesn't target specific germs—it
works the same way every time. It's like a general alarm system.
-have it when born, part of body= not learned
-it is immediate, non specific, and without memory as the first and second line of
defense against threats that are foreign
What is the first line of defense of the immune system? what are the 3 parts?
Innate immune system:
-physical (first line of defense)
-biochemical
-mechanical
what is the second line of defense for the immune system?
Innate immune system:
-inflammatory response
what is the third line of defense for the immune system?
adaptive immune system:
-naturally acquired and artificially acquired
Innate Immune System
"general defenders"
, Page 4 of 53
First line of defense: what is the physical barriers?
-physical barriers: such as our skin and the lining of our respiratory and digestive
tracts. These act like walls to keep germs out.
First line of defense: what are the biochemical layer of the innate immune
system?
-biochemical barriers, like enzymes in our saliva and stomach acid, that break
down bacteria before they can cause harm. -book = biochemical surfaces and
glandular secretions such as tears, perspiration, and earwax provide additional
means of protection
First line of defense: what are the mechanical barriers of the innate immune
system?
Mechanical barriers include things like sneezing or coughing—ways the body
physically pushes invaders out.
-also cilia in respiratory system catch stuff and move out of the respiratory tract
What is the second line of defense of the immune system if the pathogen gets
past the first line of defense?
-If germs make it past those defenses, our body activates the second line of
defense, which is the inflammatory response. This is when you might notice
redness, swelling, or warmth around a cut or infection site. It’s your body’s way of
sending immune cells to fight off the invaders.
-this is still under the innate immunity response
Acquired Immune system
"specialized fighters"
What is acquired immunity?
-also called adaptive or specific immunity
-This part of the immune system learns from past infections and creates a
targeted response. It’s slower to respond but more powerful and accurate.
-body learns and adapts to the agent
-going to learn what compromises viral or bacteria and communicate it to other cells
so they can have a targeted response to it. -adaptive immunity relies on antigen
specific receptors on T and B cells to mount a response against exposure to a threat
or disease.
what is the third line of defense in the immune system?
MED SURG EXAM 3 - IMMUNE RESPONSE AND
INFECTION CONTROL NURSING COMPREHENSIVE 2026
QUESTIONS EXAM LATEST VERSION SOLVED QUESTIONS
& ANSWERS VERIFIED 100 %
Immune Response and Infection Control
what is an infection?
–Invasion and multiplication of harmful microorganisms (pathogens) in body
tissues
-we have organisms that are not self all throughout body (skin+gut). In some cases it
helps the body, normal flora is not invasive or bad. (not made up of own bodies
genetic material and cells but body tolerates them since they are helpful and not
harmful)
-pathogen when enter the body create infectious process that involves inflammation.
non self that multiplies and creates infection.
What is the inflammatory response?
–The body’s nonspecific (innate immune system) defense mechanism to
infection or injury
-bodies response to tissue damage due to the infection. tissue damage brings on the
inflammatory response. it involves vasodilation, capillary permeability = warmth,
swelling, redness, pain
for a immune response to be initiated what must happen?
-for an immune repsonse to occur, the foreign antigen must be recognized as non
self on presentation by APCs via the MHC molecule on its surface
🧠 What Are APCs?
APC = Antigen-Presenting Cell
, Page 2 of 53
Special immune cells that detect, “eat,” and show pieces of germs (antigens) to
other immune cells (like T cells). T cells are the cells in charge of differentiating
between self and non self when APC shows piece of antigen on MHC surface
Their job: start the immune response by telling T cells, “Here’s the invader—go
attack!”
🔹 Main Types of APCs
Macrophages – big eaters that engulf and digest bacteria and dead cells.
Dendritic cells – the best APCs; found in tissues that contact the outside (skin,
lungs, GI tract).
B cells – can also act as APCs when they bind their specific antigen through their B
cell receptor (BCR).
🍽️ How APCs “Eat” and Display Antigens
APCs engulf the pathogen (through phagocytosis or endocytosis).
Inside the cell, the pathogen is broken into tiny pieces (antigens).
The APC then attaches these pieces to a special surface protein called MHC
II (Major Histocompatibility Complex class II).
The MHC II + antigen complex is then displayed on the APC’s surface — like
holding up a “wanted poster” of the invader.
⚡️ How This Mounts an Immune Response
A Helper T cell (CD4+) comes by and recognizes the antigen on the APC’s MHC
II.
If it’s a foreign antigen (non-self), the Helper T cell activates.
The Helper T cell then releases cytokines (chemical messages) that:
Activate B cells → make antibodies
Activate Cytotoxic T cells → kill infected cells
Recruit macrophages → increase phagocytosis
What is the difference between Infection and Inflammation?
–Infection = the cause (pathogen present)
–Inflammation = the body’s response (redness, swelling, heat, pain)
*can have infection that causes inflammation (bodies response to infection) and can
have inflammation from other things
*can have infection that causes inflammation, can also have inflammation with any
sort of tissue damage (sprain ankle or cut)
, Page 3 of 53
*can you have infection without inflammation? HIV, anytime the immune system is
severly immunocompromised due to HIV/AIDS, drugs, steroids.
Can you have inflammation without infection?
-Yes: Inflammation can occur without infection (e.g., sprain)
Can you have infection without inflammation?
–Infection almost always triggers inflammation
**can you have infection w/o inflammation? HIV, drugs, meds (anything that
suppresses the immune system). if your immune system is suppressed or not
responding normally then you can infection w/o the bodies response of
inflammation. this occurs in pt that have supressed immune system or are
immunocompromised (HIV/ADIS, drugs, steroids)
What are the two main parts of the immune system?
-innate (natural) immunity, nonspecific --> first responders
-acquired (adaptive) immunity (specific) --> specialized defenders
what is innate immunity (also known as natural or nonspecific immunity)? how
many lines of defense are in innate immunity?
-This is the type of immunity we are born with, and it doesn't target specific germs—it
works the same way every time. It's like a general alarm system.
-have it when born, part of body= not learned
-it is immediate, non specific, and without memory as the first and second line of
defense against threats that are foreign
What is the first line of defense of the immune system? what are the 3 parts?
Innate immune system:
-physical (first line of defense)
-biochemical
-mechanical
what is the second line of defense for the immune system?
Innate immune system:
-inflammatory response
what is the third line of defense for the immune system?
adaptive immune system:
-naturally acquired and artificially acquired
Innate Immune System
"general defenders"
, Page 4 of 53
First line of defense: what is the physical barriers?
-physical barriers: such as our skin and the lining of our respiratory and digestive
tracts. These act like walls to keep germs out.
First line of defense: what are the biochemical layer of the innate immune
system?
-biochemical barriers, like enzymes in our saliva and stomach acid, that break
down bacteria before they can cause harm. -book = biochemical surfaces and
glandular secretions such as tears, perspiration, and earwax provide additional
means of protection
First line of defense: what are the mechanical barriers of the innate immune
system?
Mechanical barriers include things like sneezing or coughing—ways the body
physically pushes invaders out.
-also cilia in respiratory system catch stuff and move out of the respiratory tract
What is the second line of defense of the immune system if the pathogen gets
past the first line of defense?
-If germs make it past those defenses, our body activates the second line of
defense, which is the inflammatory response. This is when you might notice
redness, swelling, or warmth around a cut or infection site. It’s your body’s way of
sending immune cells to fight off the invaders.
-this is still under the innate immunity response
Acquired Immune system
"specialized fighters"
What is acquired immunity?
-also called adaptive or specific immunity
-This part of the immune system learns from past infections and creates a
targeted response. It’s slower to respond but more powerful and accurate.
-body learns and adapts to the agent
-going to learn what compromises viral or bacteria and communicate it to other cells
so they can have a targeted response to it. -adaptive immunity relies on antigen
specific receptors on T and B cells to mount a response against exposure to a threat
or disease.
what is the third line of defense in the immune system?
