Chapter 19：19章.pptx

The Nervous System and Its Defenses The Nervous System and Its Defenses A. ponent parts to the nervous system 1. CNS – Brain and spinal cord: made up of neurons, both surrounded by bone, encased with meninges 2. PNS: cranial and spinal nerves The Nervous System and Its Defenses B. Defenses of the Nervous System 1. Mainly structural A) Bony casings B) Cushion of CSF C) Blood-brain barrier D) Immunologically privileged site Diseases of the Nervous System Nervous System Diseases Caused by anisms A. Bacterial meningitis 1. Many different anisms can cause an infection 2. More serious forms caused by bacteria A) Bacterial form is mon and most patients are children Diseases of the Nervous System 3. Typical symptoms: headache, painful or stiff neck, fever, and usually an increased number of white blood cells in the CSF 4. Causative agents: Diseases of the Nervous System A) Neisseria meningitides 1) Gram-negative i 2) Commonly known as us 3) Causes the most serious form of acute meningitis a) Greatly feared because it can result in shock and death within 24 hours after infection Diseases of the Nervous System 4) Can occur in both adults and children 5) Transmission via salivary droplets 6) The presence of N. meningitis within the nervous system causes a massive response by neutrophils resulting in inflammation, which obstructs the normal flow of fluids causing infarcts Diseases of the Nervous System 7) The bacteria and leukocytes metabolize the glucose normally found in cerebrospinal fluid potentially depriving the brain of nutrients 8) In addition, N meningitis circulates in blood and produces an endotoxin that causes a drop in blood pressure leading to shock Diseases of the Nervous System B) us pneumonia 1) Referred to as the us 2) Most frequent cause munity- acquired meningitis 3) Very severe Diseases of the Nervous System C) Haemophilus influenza 1) Tiny gram-negative pleomorphic rods 2) Causes severe meningitis Dis