Animal anatomy and physiology Z
MM
,Anatomy of the Immune System Immunity of defense
Recall that the immune system has two main parts: the external barriers
and the cellular components. These two parts make up what’s called the
innate immune system. There's a third defense if all else fails, the
adaptive immune system, that you’ll learn more about in this assignment.
Skin and Mucous Membranes
The first line of defense includes the skin, which covers the body and
mucous membranes, found along the respiratory, gastrointestinal, and
urinary systems. Skin acts as a physical barrier and houses
microorganisms that help to recognize and destroy invading
microorganisms. In many species, sweat also helps to inhibit bacterial
growth.
Remember there are some species that don’t sweat as people do—cats
and dogs for example.
Organs and Tissues
The second line of defense has to do with cellular components.
These components are housed in organs and in the blood system.
The spleen is the largest immunity organ. It has both red pulp and
white pulp, which is made up of lymphoid tissue. The white pulp
contains lymphocytes that react to antigens in the bloodstream. The
lymphocytes not only remove the antigens via phagocytosis, but also
help to initiate an immune response that produces antibodies to the
antigen. The production of antibodies helps not only destroy what’s
currently in the body, but also helps the body to remember this
antigen in the future and be able to attack and destroy it if it invades
in the future.
,Unit 2 -
Immunity & defense
Lymphatic System
Lymphatic System
The lymphatic system is the next largest component of the immune
system. As you'll recall, the lymphatic system is made up of vessels and
tissues that collect and return excess interstitial fluid, lymph, to the
cardiovascular system. Along the way, the lymph is passed through a
series of tissues that filter out and destroy the invading microorganisms.
Once the lymph reaches the heart, it mixes with blood to help maintain
osmotic pressure and fluid balance.
The lymphoid tissue includes the lymph nodes, mucosa-associated
lymphatic tissue (MALT), tonsils, Peyer’s patches, and the thymus. The
lymph nodes are the easiest of the tissues to evaluate as some of them
(peripheral lymph nodes) are located near the surface of the skin.
MALT refers to lymphoid tissues found in the mucosa throughout the
animal’s body. They work much like the lymph nodes, but they aren’t
encapsulated and usually don’t show a dramatic change in size during
infection or inflammation. The purpose of these tissues is to identify
antigens and then mount an immune response to them. MALT is the
general term for all the lymphoid tissue, but it has specific names for
where it’s located.
Conjunctiva-associated lymphoid tissue (CALT) is found in the
conjunctiva, nasopharynx-associated lymphoid tissue (NALT) is found in
the nose and pharynx, and gut-associated lymphoid tissue (GALT) is
found in the gastrointestinal tract.
,Unit 2 of 7 - Immunity and defense Review
-
The immune system works to prevent harm to the body by
microorganisms.
The lymphatic system filters organisms from lymph and returns it to
the cardiovascular system.
Skin and mucous membranes comprise innate immunity, the first
line of defense.
Inflammation serves as the second line of defense.
MM
,Anatomy of the Immune System Immunity of defense
Recall that the immune system has two main parts: the external barriers
and the cellular components. These two parts make up what’s called the
innate immune system. There's a third defense if all else fails, the
adaptive immune system, that you’ll learn more about in this assignment.
Skin and Mucous Membranes
The first line of defense includes the skin, which covers the body and
mucous membranes, found along the respiratory, gastrointestinal, and
urinary systems. Skin acts as a physical barrier and houses
microorganisms that help to recognize and destroy invading
microorganisms. In many species, sweat also helps to inhibit bacterial
growth.
Remember there are some species that don’t sweat as people do—cats
and dogs for example.
Organs and Tissues
The second line of defense has to do with cellular components.
These components are housed in organs and in the blood system.
The spleen is the largest immunity organ. It has both red pulp and
white pulp, which is made up of lymphoid tissue. The white pulp
contains lymphocytes that react to antigens in the bloodstream. The
lymphocytes not only remove the antigens via phagocytosis, but also
help to initiate an immune response that produces antibodies to the
antigen. The production of antibodies helps not only destroy what’s
currently in the body, but also helps the body to remember this
antigen in the future and be able to attack and destroy it if it invades
in the future.
,Unit 2 -
Immunity & defense
Lymphatic System
Lymphatic System
The lymphatic system is the next largest component of the immune
system. As you'll recall, the lymphatic system is made up of vessels and
tissues that collect and return excess interstitial fluid, lymph, to the
cardiovascular system. Along the way, the lymph is passed through a
series of tissues that filter out and destroy the invading microorganisms.
Once the lymph reaches the heart, it mixes with blood to help maintain
osmotic pressure and fluid balance.
The lymphoid tissue includes the lymph nodes, mucosa-associated
lymphatic tissue (MALT), tonsils, Peyer’s patches, and the thymus. The
lymph nodes are the easiest of the tissues to evaluate as some of them
(peripheral lymph nodes) are located near the surface of the skin.
MALT refers to lymphoid tissues found in the mucosa throughout the
animal’s body. They work much like the lymph nodes, but they aren’t
encapsulated and usually don’t show a dramatic change in size during
infection or inflammation. The purpose of these tissues is to identify
antigens and then mount an immune response to them. MALT is the
general term for all the lymphoid tissue, but it has specific names for
where it’s located.
Conjunctiva-associated lymphoid tissue (CALT) is found in the
conjunctiva, nasopharynx-associated lymphoid tissue (NALT) is found in
the nose and pharynx, and gut-associated lymphoid tissue (GALT) is
found in the gastrointestinal tract.
,Unit 2 of 7 - Immunity and defense Review
-
The immune system works to prevent harm to the body by
microorganisms.
The lymphatic system filters organisms from lymph and returns it to
the cardiovascular system.
Skin and mucous membranes comprise innate immunity, the first
line of defense.
Inflammation serves as the second line of defense.
