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• Central Nervous System


  Consists of the brain and the spinal cord
• Peripheral Nervous System


  Composed of nerves that supply all parts of the body
• Components of the Nervous System

  • Nerves
  • Ganglia
  • Meninges
• Nerves


  Of the peripheral nervous system consist of nerve fibers that transmit sensory information and motor responses
• Ganglia


  Aggregations of these cell bodies in the PNS
• Meninges


  Membranes that cover and protect the CNS
• Defense of the Nervous System

  • The CNS is well protected by bone and meninges from invasion by pathogens
  • Phagocytes of the nervous system called microglial cells can destroy invaders that reach the brain and spinal cord
  • Blood-brain barrier - special thick-walled capillaries without pores in the brain which limits entry of substances into brain cells
• Meningitis


  Most cases of meningitis are acute, but some are chronic. Acute meningitis is acquired from carriers or endogenous organisms. Organisms gain access to the meninges directly during surgery or trauma, or spread to them in blood from other infections such as pneumonia and otitis media
• Meningitis is diagnosed by culturing cerebrospinal fluid. The fluid usually is turbid—sometimes so thick with pus that it is difficult to remove with a syringe
• Meningococcal meningitis


  The organisms colonize the nasopharynx, spread to the blood, and make their way to the meninges, where they grow rapidly
• Haemophilus meningitis is the leading cause of mental retardation in the United States and worldwide
• Among adults Streptococcus pneumoniae is the most common cause of meningitis. Organisms generally spread via the blood from lung, sinus, mastoid, or ear infections
• Listeriosis


  Another kind of meningitis, caused by Listeria monocytogenes, a small, Gram-positive bacillus that is widely distributed in
• Listeriosis is now a leading cause of infection in kidney transplant patients. In pregnant women the bacillus can cross the placenta, infect the fetus, and cause abortion, stillbirth, or neonatal death
• Brain abscesses


  Microorganisms that cause brain abscesses reach the brain from head wounds or via blood from another site. As would be expected with wounds, multispecies infections are common, and anaerobes are as likely to be responsible as are aerobes
• Rabies


  In humans the first symptoms are headache, fever, nausea, and partial paralysis near the bite site. These symptoms persist for 2 to 10 days and then worsen until the acute neurological phase of the disease ensues. Hydrophobia (fear of water) occurs as throat muscles undergo painful spasms, especially during swallowing. Aerophobia (fear of moving air) occurs because the skin is hypersensitive to any sensations. Confusion, hyperactivity, and hallucinations also occur. Within 10 to 14 days of the onset of symptoms, the patient typically goes into a coma and dies
• Herpes meningoencephalitis


  This disease often follows a generalized herpes infection in a newborn infant, child, or adult. In the middle-aged or elderly, meningoencephalitis causes confusion, loss of speech, hallucinations, and sometimes seizures. Most patients die in 8 to 10 days; survivors usually display neurological damage
• Hansen's disease


  The currently preferred name for leprosy. Severe lepromatous disease erodes bone, fingers and toes become needlelike, pits develop in the skull, nasal bones are destroyed, and teeth fall from the jaw as bone surrounding them is lost. In 2013 it was discovered that M. leprae bacilli hide from the immune system inside Schwann cells, and reprogram the
• Tetanus


  Clostridium tetani endospores are exceedingly resistant to drying, disinfectants, and heat. Boiling for 20 minutes does not kill them, and they can survive for years if not exposed to sunlight. Spores are found in all soils but especially in those enriched with manure
• Central Nervous System


  Consists of the brain and the spinal cord
• Peripheral Nervous System


  Composed of nerves that supply all parts of the body
• Components of the Nervous System

  • Nerves of the peripheral nervous system
  • Ganglia
  • Meninges
• Nerves of the peripheral nervous system

  Consist of nerve fibers that transmit sensory information and motor responses
• Ganglia


  Aggregations of cell bodies in the PNS
• Meninges


  Membranes that cover and protect the CNS
• Defense of the Nervous System

  • CNS is well protected by bone and meninges from invasion by pathogens
  • Phagocytes of the nervous system called microglial cells can destroy invaders that reach the brain and spinal cord
  • Blood-brain barrier - special thick-walled capillaries without pores in the brain which limits entry of substances into brain cells
• Meningitis


  Most cases are acute, but some are chronic. Acute meningitis is acquired from carriers or endogenous organisms. Organisms gain access to the meninges directly during surgery or trauma, or spread to them in blood from other infections such as pneumonia and otitis media
• Meningitis is diagnosed by culturing cerebrospinal fluid. The fluid usually is turbid—sometimes so thick with pus that it is difficult to remove with a syringe
• Meningococcal meningitis


  1. Organisms colonize the nasopharynx

  2. Spread to the blood

  3. Make their way to the meninges, where they grow rapidly
• Haemophilus meningitis is the leading cause of mental retardation in the United States and worldwide
• Among adults Streptococcus pneumoniae is the most common cause of meningitis. Organisms generally spread via the blood from lung, sinus, mastoid, or ear infections
• Listeriosis


  Another kind of meningitis, caused by Listeria monocytogenes, a small, Gram-positive bacillus that is widely distributed in
• Listeriosis is now a leading cause of infection in kidney transplant patients. In pregnant women the bacillus can cross the placenta, infect the fetus, and cause abortion, stillbirth, or neonatal death
• Brain abscesses


  Microorganisms that cause brain abscesses reach the brain from head wounds or via blood from another site. As would be expected with wounds, multispecies infections are common, and anaerobes are as likely to be responsible as are aerobes
• Rabies


  1. First symptoms are headache, fever, nausea, and partial paralysis near the bite site

  2. Symptoms persist for 2 to 10 days and then worsen until the acute neurological phase of the disease ensues

  3. Hydrophobia (fear of water) occurs as throat muscles undergo painful spasms, especially during swallowing

  4. Aerophobia (fear of moving air) occurs because the skin is hypersensitive to any sensations

  5. Confusion, hyperactivity, and hallucinations also occur

  6. Within 10 to 14 days of the onset of symptoms, the patient typically goes into a coma and dies
• Herpes meningoencephalitis


  This disease often follows a generalized herpes infection in a newborn infant, child, or adult. In the middle-aged or elderly, meningoencephalitis causes confusion, loss of speech, hallucinations, and sometimes seizures. Most patients die in 8 to 10 days; survivors usually display neurological damage
• Hansen's disease


  The currently preferred name for leprosy. Severe lepromatous disease erodes bone, fingers and toes become needlelike, pits develop in the skull, nasal bones are destroyed, and teeth fall from the jaw as bone surrounding them is lost. In 2013 it was discovered that M. leprae bacilli hide from the immune system inside Schwann cells, and reprogram the
• Tetanus


  Clostridium tetani endospores are exceedingly resistant to drying, disinfectants, and heat. Boiling for 20 minutes does not kill them, and they can survive for years if not exposed to sunlight. Spores are found in all soils but especially in those enriched with manure