Control of Microorganisms
Human body’s defenses
Introduction
Today, people are able to travel around the world easily, increasing our exposure to new
people, new foods, and new cultures. But as we spread out, so do diseases. Emerging and re-
emerging diseases need to be monitored and managed to prevent the pandemic spread of
disease and potential death.
National and global agencies are in place to support these efforts of prevention, but reality
predicts the inevitability of a global outbreak. Ultimately, it is the role of the immune system
to identify and fight off any organism of the body that has the potential to cause harm or
disease.
Physical and chemical barriers are our first line of defense, but active immunity comes from
the innate and specific immune defenses. A strong immune system can adapt and fight off
many infections, but as we age or overwork our bodies, we weaken our immune systems and
are more vulnerable to diseases. In order to help us and society, scientists seek to understand
and develop new and more effective treatments against diseases.
Overview of specific adaptive immunity
How does the host defend against the pathogen?
, The host defenses are a multilevel network of innate, non-specific protections and specific
immunities referred to as the first, second, and third lines of defenses.
First line of defense-nonspecific barriers that block invasion at the portal of entry. Physical
barriers include the skin and mucous membranes of the respiratory and digestive tract.
*the skin is a thick, though layer that is highly impervious and waterproof
*the flushing action of sweat glands helps to remove microbes
*the mucous membranes provide limited barrier protection as they are moist and permeable
*the mucous coat on the free surface on some membranes impedes the entry and attachment
of bacteria
*blinking and tearing flushes the eye’s surface with tears and removes irritants
*the constant flow of saliva helps carry microbes to the harsh conditions in stomach
*vomiting and defecation also evacuates noxious substances or microbes from the body
*the respiratory tract has nasal hair that traps particles, mucus which exerts a flushing action,
ciliated epithelium that flushes irritants upward and out of the lungs, reflex sneezing and
coughing
*the genitourinary tract has partial protection from the flow of urine and vaginal secretions
*resident microbiota provides microbial antagonism that can block pathogens from epithelial
surfaces and create an unfavorable environment for pathogens by competing for nutrients or
by altering local
Human body’s defenses
Introduction
Today, people are able to travel around the world easily, increasing our exposure to new
people, new foods, and new cultures. But as we spread out, so do diseases. Emerging and re-
emerging diseases need to be monitored and managed to prevent the pandemic spread of
disease and potential death.
National and global agencies are in place to support these efforts of prevention, but reality
predicts the inevitability of a global outbreak. Ultimately, it is the role of the immune system
to identify and fight off any organism of the body that has the potential to cause harm or
disease.
Physical and chemical barriers are our first line of defense, but active immunity comes from
the innate and specific immune defenses. A strong immune system can adapt and fight off
many infections, but as we age or overwork our bodies, we weaken our immune systems and
are more vulnerable to diseases. In order to help us and society, scientists seek to understand
and develop new and more effective treatments against diseases.
Overview of specific adaptive immunity
How does the host defend against the pathogen?
, The host defenses are a multilevel network of innate, non-specific protections and specific
immunities referred to as the first, second, and third lines of defenses.
First line of defense-nonspecific barriers that block invasion at the portal of entry. Physical
barriers include the skin and mucous membranes of the respiratory and digestive tract.
*the skin is a thick, though layer that is highly impervious and waterproof
*the flushing action of sweat glands helps to remove microbes
*the mucous membranes provide limited barrier protection as they are moist and permeable
*the mucous coat on the free surface on some membranes impedes the entry and attachment
of bacteria
*blinking and tearing flushes the eye’s surface with tears and removes irritants
*the constant flow of saliva helps carry microbes to the harsh conditions in stomach
*vomiting and defecation also evacuates noxious substances or microbes from the body
*the respiratory tract has nasal hair that traps particles, mucus which exerts a flushing action,
ciliated epithelium that flushes irritants upward and out of the lungs, reflex sneezing and
coughing
*the genitourinary tract has partial protection from the flow of urine and vaginal secretions
*resident microbiota provides microbial antagonism that can block pathogens from epithelial
surfaces and create an unfavorable environment for pathogens by competing for nutrients or
by altering local
