Micro Quiz

• CNS
• -brain
• -spinal cord

PNS

-composed of 3 membranes (dura, arachnoid, & pia mater) that cover/protect the brain & spinal cord

-contain CSF

-blood brain barrier--many substances in the blood cannot cross into the CSF

inflammation of the meninges

inflammation of the brain

inflammation of the brain and meninges

Bacterial

Viral

Protozoan

Prion

Bacterial meningitis

Tetanus

Botulism

Leprosy

• Can be caused by:
• *Haemophilus influenzae
• *Neiserria meningitidis
• *Streptococcus pneumoniae

• -all are frequent normal colonizers of the nose/throat
• -all have thick capsule preventing phagocytosis
• -if enter bloodstream, replicate rapidly
• -sometimes they cross BBB to cause meningitis
• -initial symptoms: fever, headache, stiff neck
• -can cause rapid death--shock/inflammation due to toxin release, can be w/in hours

• caused by:
• Clostridium tetani
• -commonly found in soil
• -releases a neurotoxin
• -toxin enters bloodstream and then CNS
• -toxin causes muscle contractions - lockjaw, muscle spasm, back and heels can bow backward
• -eventual death due respiratory muscle spasms
• -preventable with tetanus vaccine--toxiod

• caused by:
• Clostridium botulinum
• -found in soil
• -makes exotoxin in anaerobic environments (ex: canned foods)
• -exotoxin blocks nerve signals
• -results in flaccid paralysis
• -respiratory & cardiac failure
• -spores often found in honey--problem for infants < 1 year due to not having normal flora protection
• -toxin is now used therapeutically--botox

• caused by:
• Mycobacterium leprae
• -disfiguring nodules form on the body
• -means of transfer unclear
• -grows in nerve & skin cells
• -tuberculoid (neural) leprosy, lepromatous (progressive) leprosy

Poliomyelitis

Rabies

• caused by:
• poliovirus
• -infects throat & small intestine, but can get into the CNS
• -causes paralysis

• caused by:
• rabies virus
• -results in fatal encephalitis
• -virus found in animals (dogs, bats)
• -virus prolliferatres in PNS then to CNS

• African Trypanosomiasis
• caused by:
• Trypanosoma brucei
• -aka: African sleeping sickness
• -carried person to person by a vector--Tsetse fly
• -protozoan flagellate invades the CNS resulting in deterioration of the nerves
• -coma & death inevitable w/out treatment
• -drugs not very effective
• -elimination of the vector is primary approach

• -are abnormally folded proteins
• -found in brain tissue
• -cause normally folded proteins to fold abnormally
• -leads to aggregates & spongiform tissue

• Creutzfeldt-Jakob disease (CJD)
• Bovine spongiform encephalopathy (BSE) - mad cow