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.)
Mast cells, basophils, and eosinophils play an important role in the development of type
I reactions because they contain the chemical mediators histamine and heparin.
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.)
Mast cells, basophils, and eosinophils play an important role in the development of type
I reactions because they contain the chemical mediators histamine and heparin.
