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Microbial Diseases of the Nervous System and Eyes

Chapter 20
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The cns consists of
brain and spinal cord
the spinal cord is protected by
the backbone
the peripheral nervous system consists of
the nerves that branch from the CNS
two types of nerves in the pns
motor and sensory nerves
motor nerves
nerves that transfer commands from the CNS to muscles and other organs throughout the body
sensory nerves
nerves that trasmit information to the CNS concerning events in the body and environmental stimuli
the cns is covered by how many protective layers
3
meninges
the 3 protective layers covering the CNS
where is cerebrospinal fluid
it circulates between the space in the meninges and in the ventricles of the brain
blood vessels that supply the CNS are composed of tightly joined cells that form
the blood brain barrier
what does the blood-brain barrier do
prevents most microbe and large molecules in the blood from entering the cerebrospinal fluid that fills the subarachnoid space
csf (cerebrospinal fluid) acts as a
shock absorber
csf provides
nutrient and oxygen to the CNS and removes wastes
spinal tap
the surgical procedure for removing CSF from the lumbar region of the spinal cord
how do microorganisms enter the CNS 4 ways
through trauma, along peripheral nerves, and through the bloodstream and lymphatic system
meningitis
an infection in the meninges
encephalitis
an infection of the brain
2 types of ccells of the nervous system
neuroglia and neurons
neuroglia
supportive cells of the NS that provide scaffolding, insulation, nutrition or defense
neurons
cells that generate and transmit nerve impulses
Grouped together, nerve cell bodies form a
ganglion
structure of the neurons
nucleus, axon and dendrites
where is the nucleus of a neuron found
in the cell bodies of neurons
dendrites
carry impulses toward the cell body
axon
carries impulses away from the cell body
axonal transport
the cytoskeleton transport system within the axon
the terminal ends of axons have branches that form junctions called
synapses
synaptic cleft
the space between an axon and a neighboring cells
what does synaptic cleft do
stops the transmission of electrical signals
how do you bridge the gap of a synaptic cleft
an axon terminal releases neurotransmitters into the synaptic cleft
neurotransmitters
chemical messengers
how do microorganisms get into the cns
through breaks in the barriers or through the PNS
how do microbes carried in the blood or lymph penetrate the blood-brain barrier
by infecting and killing cells of the meninges, causing meningitis
one bacterial disease of the nervous system
bacterial meningitis
four things that may cause meningitis
viruses, bacteria, fungi, protozoa
the 3 major causes of bacterial meningitis are
Haemophilus influenzae, streptococcus pneumonae, neisseria meningitidis
what is the most common cause of meningitis in children under four
Haemophilus influenzae
what kind of vaccine is available for Haemophilus influenzae
a conjugated vaccine directed against the capsular polysaccharide antigen
Neisseria Meningitis causes
Meningococcal Meningitis
Neisseria meningitis is a bacterium found in the
throat
how does Neisseria Meningitis gain access to the meninges
through the bloodstream. may be found in leukocytes in the CSF
Streptococcus Pneumoniae causes
pneumococcal meningitis
S. pneumoniae is commonly found in the
nasopharynx
name 4 other causes of meningitis
listeriosis, tetanus, botulism, leprosy
2 groups of people most susceptible to s. pneumoniae meningitis
hospitalized patients and young children
what is the most common cause of meningitis in adults
streptococcus meningitis
listeriosis is caused by (bacteria)
listeria monocytogenes
listeriosis is spread by
food
listeriosis affects mostly ___ and causes______
pregnant women; abortion or stillborn infant
tetanus is caused by
a localized infection of a wound by clostridium tetani
What type of bacteris is c. tetani
obligate anaerobic endospore gram-positive bacterium
where is c. tetani usually found
in the soil
C. tetani produces what kind of toxin
neurotoxin
acquired immunity for tetanus comes from
dtp immunization
Botulism is caused by
an exotoxin produced by C. botulinum
what kind of bacteria is c. botulinum
obliigate anaerobic endspore gram-positive bacterium
what kind of toxin is botulism
neurotoxin
what does the toxin from c. botulinum do
inhibits the transmission of nerve impulses
leprosy is caused by
mycobacterium leprae
besides leprosy, what else does mycobacterium leprae cause
Hansen's disease
how is mycobacterium leprae cultured
in armadillos and mouse footpads
the tuberculoid form of leprosy is characterized by
loss of sensation in the skin surrounded by nodules
the progressive form of leprosy is also called
lepromatous
in the progressive form of leprosy the disease is characterized by
disseminated nodules and tissue necrosis occurs
how is leprosy spread
by prolonged contact with exudates
how are patients with leprosy treated
with chemotherapy
viral meningitis aka
aseptic meningitis
which is the mildest type of meningitis
viral meningitis
viral meningitis results from ______ which are transmitted via ________ to infect the ______
from infection of enteroviruses which are transmitted via fecal contamination of food, water or hands and spread via the bloodstream to infect the meninges
best prevention for viral meningitis
hand washing
what are the reservoirs for poliovirus
humans
how is poliovirus transmitted
by the ingestion of water contaminated with feces
what does the salk vaccine involve
injection of formalin inactivated viruses and boosters every few years
the sabin contains
three attenuated live strains of poliovirus and is administered orally
how can polio be eliminated
through vaccination
how can rabies be contracted
through the bite of a rabid animal, by inhalation of aerosols, or invasion through minute skin abrasions
where does rabies multiply
in skeletal muscle and connectve tissue
rabies is a
zoonosis
four viral diseases of th NS
Viral meningitis, poliomyelitis, rabies, arboviral encephalitis
what isi the best way to control encephalitis
control of the vector
arboviruses that case encephalitis are transmitted by
mosquitoes
one protozoan disease of the nervous system
african trypanosomiasis
african trypanosomiasis is caused by
the protozoan trypanosoma
is there a vaccine for african trypanosomiasis if not why not
no because the protozoan is able to change it's surface antigens
2 ns disases caused by prions that are transferable from one animal to another
sheep scrapie and bovine spongiform encephalopathy
2 human diseasees similar to scrabi
Creutzfeldt-Jakob disease and kuru
kuru occurs in
isolated groups of cannibals who eat brains
chronic fatigue syndrome may be triggered by
viral illnesses such as infections mononucleosis, Q fever, lyme disease
chronic fatigue syndrome aka
myalgic encephalomyelitis