Upgrade to remove ads
Only $35.99/year

Micro Ch 20 - Whole chptr

Terms in this set (83)

Nervous System parts
Central and Peripheral
Basic Cell Types of Nervous System
Neuroglia and Neurons
Neuroglia
F: support, insulation, nutritive support, and phagocytize microbes
Central Nervous System
composed of brain and spinal cord F: master control center of the body
Cerebrum
voluntary muscle control, perception, thinking
Cerebellum
involuntary body movement
Brain stem
control of breathing, heart rate, and blood pressure
CNS environment
axenic- free of microbes
Pathogens access CNS by
breaks in the bones and meninges, medical procedures, and traveling in peripheral neurons to the CNS
Meningitis
infecting and killing cells of the meninges when microbes penetrate the blood-brain barrier
Bacteria cause disease in Nervous System by
infecting cells or growing elsewhere and releasing toxins that affect neurons
Examples of infecting cells of the nervous System
meningitis and leprosy
Examples of release of toxins that affect neurons
botulism and tetanus
Neurons
F: generate and carry signals as electrical signals
Cell body
contains nucleus
Ganglion
collection of many neuron's cell bodies
Appendages to Cell Body
Axons and dendrites
Most Common Bacterial Infection of the Nervous System
Bacterial Meningitis - inflammation of the pia mater and arachnoid mater
Bacterial Meningitis- Signs and Symptoms
sudden high fever, severe meningeal inflammation, encephalitis, increased number of WBC in the CSF
Inflamed Cranial meninges
severe headache, vomiting, pain
Inflamed spinal meninges
stiff neck, altered muscle control
Encephalitis
infection of the brain that causes deafness blindness behavioral changes, coma, and death
Bacterial Meningitis- Pathogens
5 species that cause 90% of cases 1) S. pneumoniae 2) N. meningitidis 3) H. influenzae 4) L. monocytogenes 5) S. agalactiae
Streptococcus pneumoniae
leading cause of bacterial meningitis in adults
Neisseria meningitidis
Gram - cause of bacterial meningitis- due to fimbria, capsule and lipooligosaccharide (13 strains A B C W135 in humans) ((MENGINOCOCCAL MENINGITIS))
Haemophilus Influenzae
leading cause of BM prior to vaccine
Listeria Monocytogenes
BM in fetuses, pregnant women, elderly and immunocompromised individuals
Streptococcus agalactiae
BM in newborns
BM- Pathogenesis
S. agalactiae acquired during birth, Listeria transmitted via contaminated food, other via respiratory droplets
BM- Epidemiology
S. pneumoniae present in throat of 75% of humans without causing harm, not spread by casual contact
BM- Diagnosis, Treatment, and Prevention
Diagnosis: based on symptoms and spinal tap(reveals CSF is milky) Treatment: antimicrobial drugs Prevention: vaccines available for S. penumoniae, H. influenzae type B, and N. meningitidis AVOID HIGH RISK FOODS
Botulism- Pathogen
intoxication caused by Clostridium botulinum toxin producing 1 of 7 toxic factors
Botulism- Three Forms
Food borne, infant, and wound botulism
Food-borne botulism
progressive paralysis of all voluntary muscles, blurred vision Death from paralysis of diaphragm
infant Botulism
**MCCase bacteria grow in the intestines, producing non-specific symptoms // toxin is not ingested, bacterium grows in infant's GI tract
Wound botulism
symptoms like those of food-borne botulism// growth of bacterium in dead tissue following introduction of endospores into wounds
Botulism- Epidemiology
Rare, only 50 cases per year --** most common: infant botulism
Botulism- Diagnosis, Treatment, Prevention
Diagnosis: symptoms Treatment: repeated washing of intestinal tract, administration of botulism immune globulin, and treatment with antimicrobial drugs (infant and wound) Prevention: destroying endospores in contaminated food through proper canning
Viral Disease of the Nervous System
viruses can more readily cross the blood-brain barrier, occur more frequently than bacterial and fungal infections
Viral Diseases of the NS
meningitis, polio, rabies, encephalitis
Viral Meningitis- Signs and Symptoms
similar to bacterial meningitis, usually milder than bacterial or fungal meningitis
VM- Pathogens and Virulence Factors
90% of cases caused by viruses in the genus Enterovirus family PICONAVIRDIAE (+ssRNA) **most common coxsackie A virus coxsackie B virus and echovirus
VM- Pathogenesis
damage to cells in the meninges triggers meningitis
VM- Epidemiology
more common than bact/fungal meningitis // spread through respiratory droplets and feces
VM- Diagnosis, Treatment, and Prevention
Diagnosis: signs/symptoms that occur in the absence of bacteria in the CSF Treatment: no specific one // Prevention: hand antisepsis, avoiding crowded swimming pools, limit spread
Enteroviruses
spread via the bloodstream to infect other organs including the meninges (( CALLED VIREMIA))
Poliomyelitis kinds
causes four conditions: 1) asymptomatic (90% of cases) 2) minor polio 3) nonparalytic polio 4) paralytic polio
Minor Polio
temporary fever, headache, malaise, and sore throat
Nonparalytic Polio
Minor polio symptoms plus muscle spasms and back pain
Paralytic Polio
paralysis
Polio Treatment
None, but "iron lungs" are used to assist the paralyzed respiratory muscles of polio patients// can get polio (salk and Sabin) vaccine though!
Rabies- Signs and Symptoms
pain or itching at site of infection, fever, headache, malaise, and anorexia seizures, disorientations, hallucinations
Rabies- Epidemiology
zoonosis- spread from animal resevoirs to humans-- urban areas - most common is dog in wild, skunk, fox, raccoon, badgers, bats, cats // Tranmission in the saliva spread via a bite or breaks in the skin, sometimes inhalation
Rabies- Diagnosis, Treatment, and Prevention
Diagnosis: symptoms Treatment: treatment of site of infection, antirabies serum, HRIG Prevention: Rabies vaccine (HDCV- human diploid cell vaccine)
Mycoses of the NS
fungal diseases that spread from the lungs to the CNS via the blood //
Neurological Problems and Hallucinations
poisoning from mushroom toxins
Fungi can produce
fungal meningitis
Protozoan diseases of the NS
rare, two examples: african sleeping sickness and meningoencephalitis
Meningocephalitis
caused by Acanthamoeba-- enter hosts through cuts or scrapes in the skin, eyelid, of through inhalation
African Sleeping Sickness- Signs and Symptoms
lesion of dead necrotic tissue, presence of parasite in lood with fever headaches swelling of lymphnodes, and invasion of the CNW resulting in meningoencephalitis
Meningocephalitis- Signs and Symptoms
headache, abnormal neurological function, and extreme drowsiness--- become so lethargic they dont eat
ASS- Epidemiology
from the bloodsucking tsetse fly that spreads T. brucei areas of Africa mostly
ASS- Diagnosis, Treatment, and Prevention
Diagnosis: observation of trypanosomes Treatment: pentamidine and suramin Prevention: insecticides, no current vaccine
Meningocephalitis- Epidemiology
enter through cuts or scrapes, covering of the eye, or inhalation-- rareeeee
meningocephalitis- Diagnosis, Treatment, and Prevention
Diagnosis: detect amoebae in scrapings of eye, CSF, and bipsy of brain Treatment: Miconazole, sulfadiazine, and tetracycline Prevention: difficult == avoid waterways where it is endemic, sterilize!
Prion
infectious protein
Prion Disease - Pathogen
Spongiform encephalopathies = pathogen
Prion Disease examples
scrapie (sheep) and mad cow disease- leaves the brains of victims full of holes
Prion Disease- Epidemiology
contracted by eating meat from infected cattle
synapses
terminal ends of axons
action potential
electrical signal traveling down the axon
neurotransmitter actions
1) gland to secrete another neuron to carry a nerve impulse or muscles to contract or 2) inhibition of these
most common BM today
N. meningitidis & S. pneumonia
Only type of BM that becomes epidemic
Meningococcal Meningitis
BM- Treatment
erthryomycin, chloramphenicol, aminoglycsides, ceftriaxone
Meningococcal- Treatment
rifampin, tetracycline, sulfonamides
Leprosy
Hansen's Disease- M. Leprae -- treated with rifampin and dapsone
Botulism
blocks ACl secretion in muscle contraction
Tetanus
Clostridium tetani-- tightened jaw and muscles //muscle spasms treat : penicillin
viral meningitis aka
aseptic meningitis
Rabies - Pathogen
Rhabdovirus genus lyssavirus family rhabdovirdiae
cytococcus meningitis- Pathogen
C. neoformans
cryptococcus meningitis - treatment
amphotericin B
Sets with similar terms