Spread of Bacterial Spread of Bacterial InfectionInfection

Bacteria which cause disease are Bacteria which cause disease are called PATHOGENS.called PATHOGENS.

Once pathogenic bacteria enter body Once pathogenic bacteria enter body they produce TOXINSthey produce TOXINS

Toxins travel through body via bloodToxins travel through body via blood

Fighting Bacterial Fighting Bacterial Diseases:Diseases:

– SweatSweat on skin kills some bac. on skin kills some bac.– TearsTears with enzymes destroy some bac. with enzymes destroy some bac.– Mucous Mucous traps and causes you to cough traps and causes you to cough

up bac.up bac.– Cilia Cilia in respiratory tract catch and in respiratory tract catch and

remove bac.remove bac.– Stomach AcidStomach Acid destroys some bac. destroys some bac.

Internal Defenses – Immune Response:Internal Defenses – Immune Response:

White blood cells enter infected tissue White blood cells enter infected tissue & destroy pathogens through & destroy pathogens through phagocytosisphagocytosis

Undigested pathogens stimulate the Undigested pathogens stimulate the lymph nodes to produce memory cells lymph nodes to produce memory cells and plasma cellsand plasma cells

Plasma cells make antibodies designed Plasma cells make antibodies designed to destroy that specific pathogen.to destroy that specific pathogen.

Antibodies circulate through the Antibodies circulate through the blood stream to fight any remaining blood stream to fight any remaining pathogenspathogens

• Memory cells are stored in the lymph nodes. They contain the instructions of how to make antibodies for that specific pathogen if it ever enters body again. (Fig.4 pg. 122)

Immunity to Bacterial Immunity to Bacterial Diseases:Diseases:

1.1. Active ImmunityActive Immunity – the body makes antibodies – the body makes antibodies to fight a specific disease, can also get this to fight a specific disease, can also get this through use of vaccines.through use of vaccines.

VaccineVaccine – injection of dead or weakened – injection of dead or weakened pathogen to stimulate the immune response.pathogen to stimulate the immune response.

2.2. Passive ImmunityPassive Immunity – antibodies are put into – antibodies are put into the bloodstream either naturally or by injection the bloodstream either naturally or by injection of antibioticsof antibiotics

NaturalNatural – pass from mother to fetus during last – pass from mother to fetus during last month of pregnancymonth of pregnancy

AntibioticsAntibiotics – any natural product which inhibits – any natural product which inhibits the growth of another living organism, many the growth of another living organism, many are fungi, eg:are fungi, eg:

Antibiotic Resistance:Antibiotic Resistance: Antibiotics first discovered in 1940’sAntibiotics first discovered in 1940’s More than 250 naturally-occurring antibiotics to More than 250 naturally-occurring antibiotics to

treat infectionstreat infections Over past 60 years bacteria been developing Over past 60 years bacteria been developing

resistance to antibioticsresistance to antibiotics When first exposed to antibiotics, weaker strains When first exposed to antibiotics, weaker strains

of bacteria dieof bacteria die Surviving bacteria may have slight genetic Surviving bacteria may have slight genetic

differencedifference These reproduce and pass on difference These reproduce and pass on difference

(resistance)(resistance) *70% of all antibiotics made are fed to livestock, *70% of all antibiotics made are fed to livestock,

often added to healthy animals’ feed.often added to healthy animals’ feed. The Eyes of Nye-09-(Antibiotics)The Eyes of Nye-09-(Antibiotics)