Chapter 26 Flashcards
What is the central nervous system?
Brain and Spinal cord
What is the peripheral nervous system?
Nerves
What protects the brain?
The skull and three meninges (the dura mater, arachnoid mater, and pia mater).
What are tissues of the PNS and CNS formed out of?
Glial cells and neurons.
Does the CNS have a normal microbiota?
No, bc of blood-brain barrier.
What is encephalitis or meningitis?
Inflammation of the brain or meninges caused by infection (breach blood-brain barrier). Can lead to blindness, deafness, coma, and death.
What types of bacteria can cause bacterial meningitis?
Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae, and Streptococcus agalactiae (group B streptococci) (vaginal microbiota)
How are Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae spread?
Person to person by respiratory secretions.
Who does H. influenzae primarily affect?
Young children and neonates
What are the effects of and who does N. Meningitidis or Meningococcal Meningitis infect?
Nonfatal cases can result in irreversible nerve damage (hearing loss and brain damage, or amputation of extremities because of tissue necrosis).
Its prevalence is highest among infants, adolescents, and young adults.
N. meningitidis has a high affinity for mucosal membranes (IgA protease) in the oropharynx and nasopharynx.
What is a unique sign of meningococcal meningitis?
The formation of petechial rash on the skin or mucous membranes, characterized by tiny, red, flat, hemorrhagic lesions.
Why does the rash caused by M. meningitis occur?
This rash is a response to LOS endotoxin and adherence virulence factors that disrupt the endothelial cells of capillaries and small veins in the skin → triggers the formation of tiny blood clots, causing blood to leak into the surrounding tissue → infection progresses (the levels of virulence factors increase) → the hemorrhagic lesions can increase in size as blood continues to leak into tissues. Lesions larger than 1.0 cm usually occur in patients developing shock.
Who does S. pneumoniae or Pneumococcal meningitis mostly affect?
Young children
What are the major virulence factors produced by S. pneumoniae?
PI-1 pilin for adherence to host cells (pneumococcal adherence) and virulence factor B (PavB) for attachment to cells of the respiratory tract; choline-binding proteins (cbpA) that bind to epithelial cells and interfere with immune factors IgA and C3; and the cytoplasmic bacterial toxin pneumolysin that triggers an inflammatory response.
Who does S. agalactiae affect?
Newborns during or shortly after birth,
What is S. agalactiae?
The infant initially becomes infected by S. agalactiae during childbirth, when the bacteria may be transferred from the mother’s vagina. Signs and symptoms of early onset disease include temperature instability, apnea (cessation of breathing), bradycardia (slow heart rate), hypotension, difficulty feeding, irritability, and limpness.