Miicrobiology Lecture- Chapter 22 Microbial Diseases of the Nervous System
Does the nervous system have any normal microflora?
The human nervous system is divied into 2 major components:
Central Nervous System-
Peripheral Nervous system-
-nerves extending from the spinal cord
Bacteria in the nervous system can do great damage.
Because the central nervous system is the control mechanism for our body and bacteria causing disease in there is very serious.
CNS protection from physical damage:
Bone- The brain is encased in the skull
spinal cord within the vertebrae
Meninges- 3 protective layers
Blood Brain Barrier-made up of cerebral capillaries
The nervous system doesn't have phagocytic cells exactly but the do have __________ cells that have phagocytic capability that are unique to the nervous system.
The meninges are __________.
3 sheets of connective tissue that protect and encircle the brain and spinal cord.
The 3 layers of the meninges are:
Exterior to closest to brain:
Cerebrospinal fluid is located?
A normal weight individual has how many mL of cerebrospinal fluid?
Why would it be bad if you cracked your skull open and some microbes got into your CNS?
The CNS has little to no:
Lacking the complement system their is no lysing of foreign invaders, no enhancement of phagocytosis and no innate system to trigger the adaptive immune system.
The blood brain barrier consists of 3 layers of _________.
Characteristics of the BBB are:
highly selective as to what gets through
-some substances can cross into the brain
-substances that typically cross are lipid soluble
In cases where medicines are needed to be taken for disease in the CNS what needs to be different about these medicines than in other parts of the body?
True or false capillaries in BBB are leaky in diseased state?
Inflammation as a result of infection makes ______ more ________ .Which in turn would let drugs cross over easier.
The BBB is 3 layers
Feet of astrocytes
-which are specific to NS
The endothelial cells are held together by protein staples called?
tight junctions- nothing gets a crossed
Diseases of the NS
inflammation of the meninges
inflammation of the brain
inflammation of the meninges and brain
True or false a lot of viruses that cause diseases causes humans to have flu like symptoms?
True or false humans and horses are often affected by the same viruses?
inflammation of the meninges
Maybe caused by variety of microbes
usually caused by viruses
way more serious when caused by
Meningitis is diagnosed by
sample of CSF taken from between the 3rd and 4th lumbar region.
If the CSF is turbid and thick what does that mean?
that the CSF is infected and hard to extract from the lumbar region
How do you ID the bacteria from CSF?
latex agglutination tests
-latex made for the most common bacterial causes of meningitis
-clumps it is positive for that bacteria
- not good for less common bacteria or viruses
Bacterial nerve diseases: they are neuroparalytic
Hansen disease- Leprosy
Hansen's disease is caused by
-only bacterium known to cause damage to the PNS
-slow growing ( 12 days to replicate from 1--->2 cells
-acid fast bacteria
Tetanus is caused by
-spore forming bacillus
Botulism caused by
Clostridium botulinum- most potent toxin known to man
mainly due to food poisoning- ingestion of spores
There are 3 types of botulism
wound- rarest form
In Hansen's disease (Leprosy) people tend to be ____________.
asymptomatic at first
Hansen's disease destroys ________ and _________.
Mycobacterium travel to _______ areas of the body such as appendages, ears, skin and nose.
The Island of Molokai was _____________.
A leper colony where people with Hansen's disease were sent to live out their natural lives with no medical attention
Tetanus symptoms are:
lockjaw (one of the first signs)
Tetanus prevents ______________.
muscle relaxation- death usually due to asphyxia if respiratory muscles are affected
In tetanus the _________ is causing the problem not the _________.
Clostridium tetani is
obligate anaerobe- O2 kills it
In tetanus the bacteria is preventing the glycine signal to be released so it doesn't prevent _______
from being disbursed causing constant contractions no muscle relaxation.
If someone steps on a nail and gets a puncture wound and needs quick attention and not immunized they receive the __________
TIG - tetanus immune globulin which immediately makes mass # of antibodies
If a person who is immunized against tetanus has the same scenario they receive the ______
1 million cases of tetanus world wide over 1/2 are in _________.
Botulism is derived from the Latin meaning _______ and is ______ shaped. Even a taste of this can be fatal.
Botulism produces ________ which affects neuromuscular junction.
Infant botulism was first discovered in 1976. Also referred to as _______________.
floppy baby syndrome (flaccid state)cannot contract muscles
Should infants be given honey?
Food botulism is the most common. Caused by _______.
Intoxication- caused by toxin not bacteria
True or false 1 ounce can kill the entire U.S. population.
True or false. In California 10% of the jars of honey sold contain botulism.
Wound botulism is introduced deep enough to be in an _________ environment.
Wound botulism is:
least common form of botulism
no more than 1 case per year in the U.S.
occurs in deep wounds
Tissue damage impairs circulation
Toxins reach tight junctions between neurons and muscle cells
Positive form of botulism
relaxes muscles to wrinkle less