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Nervous and Eye Diseases: Lecture 1 (Peripheral Nervous System (neuroglia,…
Nervous and Eye Diseases: Lecture 1
Nervous system
central nervous system
brain and spinal cord
cerebrum: largest part; controls voluntary muscles and thinking
cerebellum: controls body movements and balance
brain stem: connects brain to cord and controls vital signs
spinal cord: from brain stem to lumbar region
below lumbar is bundle of nerves- cranium equina- extends to cord
dura mater-lies next to bones that covers all soft organs of CNS
arachnoid mater-has numerous branching fibers
subarachnoid space-space sits between dura mater and pia mater
pia mater-internal layer, presses close to spinal cord and brain, supplies CNS with blood
blood brain barrier- blood vessel walls are tightly joined together and not alot of path or meds cross
cerebral spinal field
fluid leaks into subarachnoid space and circulates and bathes the organs
acts as a shock absorber, give nutr, and electrolytes and O2 to nervous tissue; removes waste products
lumbar puncture- needle b/t two lumbar vertebrae through dura mater and subdural space
arachnoid villi: extend into a blood-filled cavity at the top of the cranium and return CSF to blood
Peripheral Nervous System
made of nerves that transfer commands to CNS
cranial nerves- from brain through holes in cranial bones
spinal nerves- extend from spinal cord through vertebral gaps
sensory
carry signals toward CNS
motor
carry signals away from CNS
mixed
carry signals both toward and away CNS
neuroglia
provides support, insulation, and nutriton
phagocytize microbes
Neurons
carry nerve impulses
nucleus lies in region-cell body
Ganglion
collection of many neurons cells bodies
dendrites and axons extend from cell body
synapse
junction at terminal ends of axon
helps bring on signal transfer
neurostransmitter
can stimulate or inhibit
chemical signals
Bacteria
CNs has no openings to allow for microbe colinization
a closed system- called axenic enviornment
enter by bone break and meninges
enter through medical procedure
can travel in peripheral neurons to CNS
inflam can cause/alter permeability to blood brain barrier
can infect cells of nervous system
bacteria can grow elsewhere and release toxins that affect neurons
Bacterial Meningitis
s/s: sudden onset fever(105+), increased blood cell count in CSF, swelling slows norm flow, pressure on brain, severe nausea, vomit, pain, drowsiness, confusion, irritable, stiff neck, encephalitis
can progress to blindness, deafness, coma, and death
can develop rapidly and kill wothin 6 hours
will take a lumbar puncture and see milky fluid
more than 50 different pathogens can casue bacterial type
5 types cause 90% of the cases
Neisseeria, strept. pneumoniae, Haemophilus, strep. agalactiae, listeria
Streptococcus Pneumoniae
gram + coccus with a capsule
forms short strains- has 92 different types are known to be infective in the normal microbiome
can grow in throat, lungs, sinuses, and from location can move to meninges via blood
lead cause for elderly and child
polysaccharide capsule protects bacteria
unencapsulated :one doesn't cause disease
enzymes and toxins enable to counteract immune system