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Slide 1
Plants and animals have a variety of chemical defenses against
infections that affect dynamic homeostasis. Essential Knowledge
2.D.4:
Slide 2
Plants, invertebrates and vertebrates have multiple,
nonspecific immune responses.
Slide 3
Invertebrates Invertebrate immune systems have nonspecific
response mechanisms, but they lack pathogen-specific defense
responses. innate immune system, also known as non-specific immune
system (respond in a generic way)
Slide 4
2 types of invertebrate defenses Insects' exoskeleton made
mostly of a polysaccharide called chitin, serves as an effective
barrier against microbes Phagocytosis is used to engulf bacteria
cells
Slide 5
Plants Innate Response Plant defenses against pathogens include
molecular recognition systems with systemic responses; Infection
triggers chemical responses that destroy infected and adjacent
cells, thus localizing the effects.
Slide 6
Slide 7
Vertebrate immune systems have nonspecific and nonheritable
defense mechanisms against pathogens.
Slide 8
Vertebrate nonspecific Immunity The epithelial surfaces form a
physical barrier. gastrointestinal and respiratory tract, movement
due to peristalsis or cilia helps remove infectious agents; and
mucus traps infectious agents The gut can prevent the colonization
of pathogenic bacteria by secreting toxic substances The flushing
action of tears and saliva helps prevent infection of the eyes and
mouth. Inflammation is one of the first responses of the immune
system to infection or irritation. Ex: histamine
Slide 9
All white blood cells (WBC) are known as leukocytes. Leukocytes
are different from other cells of the body in that they are not
tightly associated with a particular organ or tissue; thus, they
function similar to independent, single-celled organisms.
Leukocytes are able to move freely and interact with and capture
cellular debris, foreign particles, or invading microorganisms.
Unlike many other cells in the body, most innate immune leukocytes
cannot divide or reproduce on their own, but are the products of
multipotent hematopoietic stem cells present in the bone marrow.
The innate leukocytes include: Natural killer cells, mast cells,
eosinophils, basophils; and the phagocytic cells including
macrophagess, neutrophilss and dendritic cells, and function within
the immune system by identifying and eliminating pathogens that
might cause infection.
Slide 10
All white blood cells (WBC) are known as leukocytes. Leukocytes
are different from other cells of the body in that they are not
tightly associated with a particular organ or tissue; thus, they
function similar to independent, single-celled organisms.
Leukocytes are able to move freely and interact with and capture
cellular debris, foreign parti es, or invading microorganisms.
Unlike many other cells in the body, most innate immune leukocytes
cannot divide or reproduce on their own, but are the products of
multipotent hematopoietic stem cells present in the bone marrow.
The innate leukocytes include: Natural killer cells, mast cells,
eosinophils, basophils; and the phagocytic cells including
macrophagess, neutrophilss and dendritic cells, and function within
the immune system by identifying and eliminating pathogens that
might cause infection.
Slide 11
Slide 12
The mammalian immune system includes two types of specific
responses: cell mediated and humoral Cell-mediated immunity is an
immune response that does not involve antibodies but rather
involves the activation of phagocytes, antigen-specific cytotoxic
T-lymphocytes(a type of white blood cell), and the release of
various cytokines in response to an antigen Cell-mediated immunity
is directed primarily at microbes that survive in phagocytes and
microbes that infect non-phagocytic cells. It is most effective in
removing virus-infected cells, but also participates in defending
against fungi, protozoans, cancers, and intracellular
bacteria.
Slide 13
Humoral In the humoral response, B cells, a type of lymphocytic
white blood cell, produce antibodies against specific antigens.
Humoral immunity is so named because it involves substances found
in the humours, or body fluids. The principal function of B cells
is to make antibodies
Slide 14
Antibodies are proteins produced by B cells, and each antibody
is specific to a particular antigen. A second exposure to an
antigen results in a more rapid and enhanced immune response. What
are memory T-cells? Memory T-cells are derived from normal T-cells
that have learned how to overcome an invader by remembering the
strategy used to defeat previous infections. (adaptive
immunity)