NURS 231 Pathophysiology Exam 3 Questions
With Verified Answers
innate immunity
Innate immunity, also called natural immunity, is the first line of defense. This type of defense is in
place before an infection takes place and can function immediately. It is comprised of physical,
chemical, cellular, and molecular defenses.
How does the skin act as a physical barrier?
The skin's design makes it a strong physical barrier. It has closely packed cells in multiple layers that
are continuously being shed. Keratin covers the skin, which creates a salty, acidic environment
inhospitable to microbes. It also contains antimicrobial proteins and lysozymes that inhibit
microorganisms and help to destroy them.
What cells are involved in innate immunity?
neutrophils
macrophages
dendritic cells (DC)
natural killer (NK) cells
intraepithelial lymphocytes
Describe each type of leukocyte and explain their function.
Neutrophils are the most abundant in the body and are an early responder in innate immunity and
use phagocytosis to kill microbes.
Eosinophils are active in parasitic infections and allergic responses.
Basophils release histamine and proteolytic enzymes.
Monocytes are the largest in size and are released from the bone marrow and mature into
macrophages and dendritic cells where they engage in the inflammatory response and phagocytize
foreign substances and cellular debris.
Macrophages have a long life span, reside in the tissues, and are the first phagocyte that organisms
encounter.
Neutrophils and macrophages work together on behalf of the host's initial defense system.
adaptive immunity
Adaptive immunity, also called acquired immunity, is the second line of defense and includes both
humoral and cellular mechanisms that respond to cell-specific substances known as antigens.
Adaptive immunity is acquired through previous exposure to infections and other foreign agents. It
can not only distinguish self from nonself but can recognize and destroy specific foreign agents based
on their different antigenic properties. This response takes more time but is extremely effective.
antigens
Antigens are present on the surface of pathogens or other foreign substances that elicit the adaptive
immune response.
What are the primary cells of adaptive immunity?
The primary cells of the adaptive immune system are the lymphocytes, APCs (antigen presenting
cells), and effector cells.
Describe B & T lymphocytes and discuss their role in immunity:
, B lymphocytes produce the antibodies (humoral immunity) and T lymphocytes provide the cell-
mediated immunity. B and T lymphocytes have the unique function as the only cells to recognize
specific antigens present on the surface of pathogens and to remember them in the future.
table 3.1 (difference between innates and adaptive immunity)
function of humoral immunity
Humoral immunity is mediated by B-lymphocyte activation and subsequent antibody production. It is
the main defense against extracellular microbes and toxins.
B lymphocytes function in humoral immunity to produce antibodies.
5 classes of immunoglobulins
IgG (gamma globulin) makes up approximately 75% of the total circulating antibodies. It is a large
molecule that has antiviral, antibacterial, and antitoxin properties. It is present in all body fluids,
readily enters the tissues, and crosses the placenta to give immunity to the fetus.
IgA is the second most common, comprising approximately 15% of all antibodies. It is a secretory Ig
found in saliva, tears, colostrum, and bronchial, GI, prostatic, and vaginal secretions. Its main function
is to provide local immunity on mucosal surfaces. IgA prevents the attachment of viruses and bacteria
onto epithelial cells.
IgM makes up roughly 10% of all antibodies and plays a role in the lysis of microorganisms. It is the
first antibody to be produced by the fetus and immature B lymphocytes as well as the first Ig to be
produced in response to an infection. For this reason, monitoring IgM levels is helpful clinically, as
increased levels would indicate an active (current) infection.
IgD circulates in very low levels and its functions are relatively unknown.
IgE is the least common of the antibodies, but it is responsible in inflammation and allergic responses
as well as combating parasitic infections.
function of cellular immunity
T lymphocytes make up the cellular immunity and function to activate other T and B cells, control
intracellular viral infections, reject foreign tissue grafts, activate autoimmune processes, and activate
delayed hypersensitivity reactions.
master regulator of the immune system
CD4+ helper T cells
Describe the differences between active and passive immunity
Active immunity is acquired from an immune response either via vaccination or from environmental
exposure. Active immunity is long lasting but takes days to weeks after the first exposure to fully
develop a response.
Passive immunity is immunity transferred from another source. The most common example is from
mother to fetus, where the IgG antibodies are passed on either via the placenta or breast milk or
colostrum. Passive immunity is short-term protection lasting only weeks to months.
What are type I hypersensitivity reactions?
IgE-mediated reactions that develop quickly upon exposure to an antigen.
What cells are involved in type I reactions? (Know their roles.)
With Verified Answers
innate immunity
Innate immunity, also called natural immunity, is the first line of defense. This type of defense is in
place before an infection takes place and can function immediately. It is comprised of physical,
chemical, cellular, and molecular defenses.
How does the skin act as a physical barrier?
The skin's design makes it a strong physical barrier. It has closely packed cells in multiple layers that
are continuously being shed. Keratin covers the skin, which creates a salty, acidic environment
inhospitable to microbes. It also contains antimicrobial proteins and lysozymes that inhibit
microorganisms and help to destroy them.
What cells are involved in innate immunity?
neutrophils
macrophages
dendritic cells (DC)
natural killer (NK) cells
intraepithelial lymphocytes
Describe each type of leukocyte and explain their function.
Neutrophils are the most abundant in the body and are an early responder in innate immunity and
use phagocytosis to kill microbes.
Eosinophils are active in parasitic infections and allergic responses.
Basophils release histamine and proteolytic enzymes.
Monocytes are the largest in size and are released from the bone marrow and mature into
macrophages and dendritic cells where they engage in the inflammatory response and phagocytize
foreign substances and cellular debris.
Macrophages have a long life span, reside in the tissues, and are the first phagocyte that organisms
encounter.
Neutrophils and macrophages work together on behalf of the host's initial defense system.
adaptive immunity
Adaptive immunity, also called acquired immunity, is the second line of defense and includes both
humoral and cellular mechanisms that respond to cell-specific substances known as antigens.
Adaptive immunity is acquired through previous exposure to infections and other foreign agents. It
can not only distinguish self from nonself but can recognize and destroy specific foreign agents based
on their different antigenic properties. This response takes more time but is extremely effective.
antigens
Antigens are present on the surface of pathogens or other foreign substances that elicit the adaptive
immune response.
What are the primary cells of adaptive immunity?
The primary cells of the adaptive immune system are the lymphocytes, APCs (antigen presenting
cells), and effector cells.
Describe B & T lymphocytes and discuss their role in immunity:
, B lymphocytes produce the antibodies (humoral immunity) and T lymphocytes provide the cell-
mediated immunity. B and T lymphocytes have the unique function as the only cells to recognize
specific antigens present on the surface of pathogens and to remember them in the future.
table 3.1 (difference between innates and adaptive immunity)
function of humoral immunity
Humoral immunity is mediated by B-lymphocyte activation and subsequent antibody production. It is
the main defense against extracellular microbes and toxins.
B lymphocytes function in humoral immunity to produce antibodies.
5 classes of immunoglobulins
IgG (gamma globulin) makes up approximately 75% of the total circulating antibodies. It is a large
molecule that has antiviral, antibacterial, and antitoxin properties. It is present in all body fluids,
readily enters the tissues, and crosses the placenta to give immunity to the fetus.
IgA is the second most common, comprising approximately 15% of all antibodies. It is a secretory Ig
found in saliva, tears, colostrum, and bronchial, GI, prostatic, and vaginal secretions. Its main function
is to provide local immunity on mucosal surfaces. IgA prevents the attachment of viruses and bacteria
onto epithelial cells.
IgM makes up roughly 10% of all antibodies and plays a role in the lysis of microorganisms. It is the
first antibody to be produced by the fetus and immature B lymphocytes as well as the first Ig to be
produced in response to an infection. For this reason, monitoring IgM levels is helpful clinically, as
increased levels would indicate an active (current) infection.
IgD circulates in very low levels and its functions are relatively unknown.
IgE is the least common of the antibodies, but it is responsible in inflammation and allergic responses
as well as combating parasitic infections.
function of cellular immunity
T lymphocytes make up the cellular immunity and function to activate other T and B cells, control
intracellular viral infections, reject foreign tissue grafts, activate autoimmune processes, and activate
delayed hypersensitivity reactions.
master regulator of the immune system
CD4+ helper T cells
Describe the differences between active and passive immunity
Active immunity is acquired from an immune response either via vaccination or from environmental
exposure. Active immunity is long lasting but takes days to weeks after the first exposure to fully
develop a response.
Passive immunity is immunity transferred from another source. The most common example is from
mother to fetus, where the IgG antibodies are passed on either via the placenta or breast milk or
colostrum. Passive immunity is short-term protection lasting only weeks to months.
What are type I hypersensitivity reactions?
IgE-mediated reactions that develop quickly upon exposure to an antigen.
What cells are involved in type I reactions? (Know their roles.)
