BIOS 255
(EDAPT WEEK 5)
Anatomy & Physiology III course with a lab
,Introduction to the Immune System
Introduction
During this concept, you will be introduced to the immune system. The
topics covered include:
An introduction to innate (non-specific) and adaptive (specific)
immune responses.
Compare and contrast innate (non-specific) with adaptive (specific)
defenses.
Define immunity and the immune system.
Describe the roles of the various types of leukocytes in innate (non-
specific) and adaptive (specific) immune responses.
Explain the ways in which the innate (non-specific) and adaptive
(specific) immune responses cooperate to enhance the overall
resistance to disease.
An Introduction to the Immune System
The body's ability to maintain homeostasis is highly dependent on its
ability to fight off pathologic agents. Immunity is our body’s ability to ward
off the pathogens that produce disease. The protective cells, chemicals,
and physical barriers that keep us safe from invading pathogens form the
immune system of our body. These are widely distributed with the highest
numbers present in the lymphatic system – lymph nodes, spleen, and
lymphatic vessels to name few.
There are two major forms of immunity with three lines of defense:
1. Non-specific Resistance (Innate Immunity): Fast-acting defense
mechanisms that provide general protection (non-specific) against
invasion by a wide range of pathogens. Also called inborn/ native/
genetic immunity as it is present at birth.
Non-specific defense includes both first and second line of defense:
, First line of defense: Physical and chemical barriers like skin,
mucus membranes, and sebum that block the invasion through
exposed epithelia.
Second line of defense: Internalized system of protective cells
and processes that work to prevent pathogens entering the
body. Leukocytes like neutrophils, eosinophils can destroy
pathogens in both phagocytic and non-phagocytic killing, while
macrophages perform phagocytic killing only. A differential
count of leukocytes can help in identifying infectious agents
(bacterial, viral. or parasites). Some processes that form the
second line of defense are:
o Inflammation and fever are non-specific responses
activated to enhance the activity of leukocytes.
o Interferons are chemical messengers released by cells
attacked by viruses to activate defense mechanisms in
healthy in nearby healthy cells.
o Complement system is a set of proteins activated via
three different pathways that target and destroy the cell
wall of pathogens.
1. Specific Immunity (Adaptive Immunity): Directed slow responses by
specialized lymphocytes that recognize specific foreign substances
(antigens) and develops memory of those antigens. A slow, uniquely
tailored response to a specific pathogen based on antigen
identification hence the name adaptive or acquired immunity.
Adaptive immunity forms the third line of defense, which
includes cell-mediated and antibody-mediated responses that
provide long-term specific immunity.
, Innate Immunity Adaptive Immunity
Specificity Non-specific and no Specific recognizes
and Memory memory. specific antigens.
Response Fast: Immediate, up to Slower: Several hours
Rate several hours. to several days.
Component Skin, mucus membranes, T and B
s and the lymphocytes, macrophages,
chemicals associated dendritic cells.
with these. Leukocytes:
Granulocytes and
macrophages.
Processes: Inflammation,
fever, interferons, and
the complement system.
Overview of Innate (Non-Specifc) Defenses
(EDAPT WEEK 5)
Anatomy & Physiology III course with a lab
,Introduction to the Immune System
Introduction
During this concept, you will be introduced to the immune system. The
topics covered include:
An introduction to innate (non-specific) and adaptive (specific)
immune responses.
Compare and contrast innate (non-specific) with adaptive (specific)
defenses.
Define immunity and the immune system.
Describe the roles of the various types of leukocytes in innate (non-
specific) and adaptive (specific) immune responses.
Explain the ways in which the innate (non-specific) and adaptive
(specific) immune responses cooperate to enhance the overall
resistance to disease.
An Introduction to the Immune System
The body's ability to maintain homeostasis is highly dependent on its
ability to fight off pathologic agents. Immunity is our body’s ability to ward
off the pathogens that produce disease. The protective cells, chemicals,
and physical barriers that keep us safe from invading pathogens form the
immune system of our body. These are widely distributed with the highest
numbers present in the lymphatic system – lymph nodes, spleen, and
lymphatic vessels to name few.
There are two major forms of immunity with three lines of defense:
1. Non-specific Resistance (Innate Immunity): Fast-acting defense
mechanisms that provide general protection (non-specific) against
invasion by a wide range of pathogens. Also called inborn/ native/
genetic immunity as it is present at birth.
Non-specific defense includes both first and second line of defense:
, First line of defense: Physical and chemical barriers like skin,
mucus membranes, and sebum that block the invasion through
exposed epithelia.
Second line of defense: Internalized system of protective cells
and processes that work to prevent pathogens entering the
body. Leukocytes like neutrophils, eosinophils can destroy
pathogens in both phagocytic and non-phagocytic killing, while
macrophages perform phagocytic killing only. A differential
count of leukocytes can help in identifying infectious agents
(bacterial, viral. or parasites). Some processes that form the
second line of defense are:
o Inflammation and fever are non-specific responses
activated to enhance the activity of leukocytes.
o Interferons are chemical messengers released by cells
attacked by viruses to activate defense mechanisms in
healthy in nearby healthy cells.
o Complement system is a set of proteins activated via
three different pathways that target and destroy the cell
wall of pathogens.
1. Specific Immunity (Adaptive Immunity): Directed slow responses by
specialized lymphocytes that recognize specific foreign substances
(antigens) and develops memory of those antigens. A slow, uniquely
tailored response to a specific pathogen based on antigen
identification hence the name adaptive or acquired immunity.
Adaptive immunity forms the third line of defense, which
includes cell-mediated and antibody-mediated responses that
provide long-term specific immunity.
, Innate Immunity Adaptive Immunity
Specificity Non-specific and no Specific recognizes
and Memory memory. specific antigens.
Response Fast: Immediate, up to Slower: Several hours
Rate several hours. to several days.
Component Skin, mucus membranes, T and B
s and the lymphocytes, macrophages,
chemicals associated dendritic cells.
with these. Leukocytes:
Granulocytes and
macrophages.
Processes: Inflammation,
fever, interferons, and
the complement system.
Overview of Innate (Non-Specifc) Defenses
