Defence System Flashcards
Pathogen
An organism that causes disease
Immunity
The ability to resist infection
General defence system
Acts as a barrier to all pathogens attempting to gain entry to the human body
First line of general defence
Skin
Mucous
Lysozome
Acid
First line of defence:skin
Structural barrier which prevents the entry of infections
First line of defence:mucus
Traps pathogens in sticky mucus and stops it from entering the body
First line of defence:Lysozome
Enzyme in sweat tears and saliva that dissolves the cell walls of bacteria
First line of defence:Hydrochloric acid
Acidic solution attacks and kills the pathogen
Second line of defence
Phagocytic white blood cells;phagocytes,macrophages
Defence proteins;complement, interferons
Inflammation
Phagocytic white blood cells
White blood cell that engulfs ans destroys pathogens -phagocytes
Larges phagocytes- macrophages
Some in bloodstream others stay in spleen or lymph nodes
Defence protein: Complement
A set of proteins activated in an infection that destroys pathogens and viruses
Defence proteins: Interferons
A set of proteins that prevent/INTERFERE WITH the growth of viral infections e.g colds and influenza
Second line of defence:inflammation
Chemicals are released to dilate capillaries and make it more porous to allow more white blood cells.
Generates heat and kills the bacteria
Specific defence system
Attacks particular pathogens
Third line of defence
Monocytes
Lymphocytes
Antibodies
Monocytes
Mature in macrophages
Engulf the pathogens and display the antigens found on the pathogen on its own surface
Causes antibodies to be produced
Lymphocytes
Attack cells with antigens on its surface OR
Makes antibodies
Lymphocyte B and T cells
Antigen
A foreign molecule that stimulates the production of antibodies
Antibodies
A protein produced by white blood cells in response to a specific antigen
Induced immunity
The ability to resist disease caused by a specific pathogen by the production of antibodies
Active immunity
Involves the production of a person’s own antibodies in response to foreign antigens that enter the body
Natural active immunity
Occurs when a pathogen enters the body in a normal/natural way
Artificial active immunity
Occurs when a pathogen is mediaclly introduced to the body
Vaccine
A non disease causing dose of the pathogen which triggers the production of antibodies
Passive immunity
Occurs when individuals are given the antibodies that were formed by another organism
Natural passive immunity
Ccurs when a child gets antibodies from its mother
Artificial passive immunity
When a person is given an injection containing antibodies made by another organism
Lymphocyte T cells
Mature in Thymus gland Killer T cells Helper T cells Suppressor T cells Memory T cells
Lymphocyte B cells
Mature in Bone marrow
Plasma B cells
Memory B cells
Plasma B cells
Produce antibodies
Memory B cells
Survive for years after the infection is eliminated and can make the specific antibody if the same infection later enters the body
Helper T cells
Stimulates B cells and killer T cells
Killer T cells
Destroy abnormal human body cells
Suppressor T cells
Inhibit the immune response
Memory T cells
Survived for years after the infection is eliminated and can stimulate the specific B cells and killer T cells if the same infection later enters the body
