THE IMMUNE SYSTEM
Immunity is the body’s ability to develop and maintain resistance to invasion from foreign organisms,
and to inactivate them and/or eliminate them.
The mechanisms of this involve:
— Resistance against pathogens
— Removal of debris or old cells
— Identification of abnormal or mutated cells
— Development of allergies or autoimmune diseases
º This happens when the immune response is not regulated properly and becomes harmful to
the body itself.
— Rejection of cells
º Such as rejection of an organ transplant. Another potentially harmful aspect of the immune
response.
Immunity against a disease = resistance to that pathogen
Access Points to the Body
Any opening on the body presents an access point to pathogens, including:
— GIT system
— Reproductive system
— Ears
— Respiratory tract
— Damage to skin
Natural openings such as the GIT or reproductive system are lined with mucosa (mucous membranes
consisting of epithelial tissue) which have aggregations of immune cells in them, ready to eliminate
pathogens.
Another example of defence is the naturally acidic
environment of the vagina, which is antibacterial.
, Pathogens
— Pathogens = Bacteria + Viruses
— Bacteria = single-cell micro-organisms
º Tissue damage
º Produce toxic waste which damages
tissue
Virulence = how severe or
harmful they are
Figure 1 - VERY NB!
— Viruses = nucleic acids + protein capsule (not
living cell, ∴ cant reproduce)
º Infection of host cell
Take over cellular functions of host cell
Destruction of cells
Formation of cancer cells
— Antigens:
º Are like flags or markers on a cell which identifies it
º Each organism has its own unique antigens, and thus will recognize foreign matter
º An antibody binds to the antigen of a pathogen
º The body will only develop antibodies for the pathogens to which it has already been
exposed.
— Leucocytes: (white blood cells)
º Many different types, all from one hematopoietic stem cell
º Forms two immune response systems
Immunity is the body’s ability to develop and maintain resistance to invasion from foreign organisms,
and to inactivate them and/or eliminate them.
The mechanisms of this involve:
— Resistance against pathogens
— Removal of debris or old cells
— Identification of abnormal or mutated cells
— Development of allergies or autoimmune diseases
º This happens when the immune response is not regulated properly and becomes harmful to
the body itself.
— Rejection of cells
º Such as rejection of an organ transplant. Another potentially harmful aspect of the immune
response.
Immunity against a disease = resistance to that pathogen
Access Points to the Body
Any opening on the body presents an access point to pathogens, including:
— GIT system
— Reproductive system
— Ears
— Respiratory tract
— Damage to skin
Natural openings such as the GIT or reproductive system are lined with mucosa (mucous membranes
consisting of epithelial tissue) which have aggregations of immune cells in them, ready to eliminate
pathogens.
Another example of defence is the naturally acidic
environment of the vagina, which is antibacterial.
, Pathogens
— Pathogens = Bacteria + Viruses
— Bacteria = single-cell micro-organisms
º Tissue damage
º Produce toxic waste which damages
tissue
Virulence = how severe or
harmful they are
Figure 1 - VERY NB!
— Viruses = nucleic acids + protein capsule (not
living cell, ∴ cant reproduce)
º Infection of host cell
Take over cellular functions of host cell
Destruction of cells
Formation of cancer cells
— Antigens:
º Are like flags or markers on a cell which identifies it
º Each organism has its own unique antigens, and thus will recognize foreign matter
º An antibody binds to the antigen of a pathogen
º The body will only develop antibodies for the pathogens to which it has already been
exposed.
— Leucocytes: (white blood cells)
º Many different types, all from one hematopoietic stem cell
º Forms two immune response systems
