portage pathophysiology module 3
define innate immunity Ans- 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? Ans- 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? Ans- neutrophils, macrophages, dendritic cells (DC), natural
killer (NK) cells, and intraepithelial lymphocytes.
Describe each type of leukocyte and explain their function: Ans- 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.
Describe adaptive immunity: Ans- 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.
What are antigens? Ans- 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? Ans- lymphocytes, APCs (antigen presenting cells), and
effector cells.
, Describe B & T lymphocytes and discuss their role in immunity: Ans- 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.
What is the function of humoral immunity? Ans- B lymphocytes function in humoral immunity to
produce antibodies.
What is the function of cellular immunity? Ans- 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.
What is the master regulator of the immune system? Ans- CD4+ helper T cells
Describe the differences between active and passive immunity? Ans- active is acquired from an immune
response via vaccination or environmental exposure. The host's own immune system initiates immune
response and developed memory. Passive is through another source, such as a mother's breast milk
What are type I hypersensitivity reactions? Ans- IgE-mediated reactions that develop quickly upon
exposure to an antigen
What cells are involved in type I reactions? (Know their roles.) Ans- Mast cells, basophils, and
eosinophils play an important role in the development of type I reactions because they contain the
chemical mediator histamine.
What are type II hypersensitivity reactions? Ans- Type II hypersensitivity reactions, or cytotoxic
hypersensitivity reactions, are antibody-mediated reactions. They are mediated by IgG or IgM antibodies
directed against target antigens on specific host cell surfaces or tissues.
What are autoimmune disorders? Ans- Autoimmune diseases occur when the body's immune system
fails to differentiate self-antigens from nonself antigens and mounts an immunologic response against
host tissues.
define innate immunity Ans- 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? Ans- 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? Ans- neutrophils, macrophages, dendritic cells (DC), natural
killer (NK) cells, and intraepithelial lymphocytes.
Describe each type of leukocyte and explain their function: Ans- 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.
Describe adaptive immunity: Ans- 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.
What are antigens? Ans- 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? Ans- lymphocytes, APCs (antigen presenting cells), and
effector cells.
, Describe B & T lymphocytes and discuss their role in immunity: Ans- 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.
What is the function of humoral immunity? Ans- B lymphocytes function in humoral immunity to
produce antibodies.
What is the function of cellular immunity? Ans- 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.
What is the master regulator of the immune system? Ans- CD4+ helper T cells
Describe the differences between active and passive immunity? Ans- active is acquired from an immune
response via vaccination or environmental exposure. The host's own immune system initiates immune
response and developed memory. Passive is through another source, such as a mother's breast milk
What are type I hypersensitivity reactions? Ans- IgE-mediated reactions that develop quickly upon
exposure to an antigen
What cells are involved in type I reactions? (Know their roles.) Ans- Mast cells, basophils, and
eosinophils play an important role in the development of type I reactions because they contain the
chemical mediator histamine.
What are type II hypersensitivity reactions? Ans- Type II hypersensitivity reactions, or cytotoxic
hypersensitivity reactions, are antibody-mediated reactions. They are mediated by IgG or IgM antibodies
directed against target antigens on specific host cell surfaces or tissues.
What are autoimmune disorders? Ans- Autoimmune diseases occur when the body's immune system
fails to differentiate self-antigens from nonself antigens and mounts an immunologic response against
host tissues.
