Nervous system Flashcards
two major division of the NS
CNS and PNS
components of the CNS
Cerebral hemispheres
Brainstem/cerebellum
spinal cord
Components of PNS
Cranial Nerves
Spinal Nerves/Autonomic counterparts
Outside the brain and cord
main roles of the CNS
Integrate & coordinate incoming and outgoing information
Conduct higher mental functions
Thinking
Learning
Judgement/perceptions (only place where this happens)
>
Helps interpret what is happening in surroundings
PNS role
Conduct signals/information to or away from the CNS
Connects the CNS with peripheral structures
Neuron composed of
Cell body/axon terminal (gray)
Axon (white)
Collection of cell bodies and synaptic sites in the CNS
Nuclei in CNS
Collection of cell bodies and synaptic sites in the PNS
Ganglia in PNS
Bundle of myelinated axons in the CNS
Tract in CNS
Bundle of myelinated axons (white matter) in the PNS
nerves
pathways of motor and sensory in the CNS
CNS there are different pathways for sensory and motor
pathways of motor and sensory in the PNS
When we get to the spinal nerve - this carries both motor and sensory
Mixed nerve = sensory and motor components
Supratentorial
the upper part of the brain- does notincluded the brainstem/cerebellum/spinal cord
Allows for higher functions (cognition, judgement, perception) -only place we see this
Serves motor and sensory functions
motor and sensory functions in the right brain
relates to Left body
motor and sensory functions left hemp
relates to Right body
left hemp
In most is the dominant hemp
associated with aspects of language (motor aspects speech/understanding)
Right hemp
associated with body attention/awareness/recognition
affective aspects of language
Left sided neglect
the right brain is saying they do not have anything on the left side
>
Nothing gets attended to on the left
Frontal hemp
Motor/motor planning
Higher functions
Voluntary gaze
Speech (motor)**
Parietal
Sensory/sensory integration
Body attention/awareness**
Temporal
Audition
Learning/memory
Emotion
Speech (understanding)**
Visual recognition
Occipital
vision
Visual recognition
helps us understand that we are seeing a red ball bouncing
Lateral and medial aspects homunculus
each have their own blood supply
Lesions to cerebral hemispheres lead to
“cortical” weakness & sensory patterns
(Contralateral) face, arm, trunk, leg
Motor Lesions in the cerebral hemispheres
Whole/portions of limb weakness vs. individual muscles
Sensory Lesions in the cerebral hemispheres
JPS, vibration, discriminative touch, pain & temperature
Global sensory loss only occurs at cortical and peripheral levels, not in between (BS/SC)
JPS • Joint position sense
measures the individual’s ability to perceive the position of a joint with his/her vision occluded and minimal exteroceptive cues
Infratentorial role in higher order processing
No role in higher functions (cognition, judgement, perceptions)
brainstem consists of
rostral (upper) midbrain, middle pons, and a caudal (lower) medulla
brainstem control
Areas pertaining to alertness & body vitals
Cerebellum
- all things Coordination
> When someone’s timing of movement is off, this might be cause of issue
What is the connections between hemispheres and spinal cord
via tracts
Tracts
bundles of axons w/ similar function
Different tracts carry different information
Motor tract
carries contralateral full body information
o Descending tract
Sensory tracts carry
contralateral full body information (lesion?)
o Ascending tract
Take out a tract
we remove half of the body - all body info for the opposite side of body
Tracts location
in Brainstem and spinal cord
Spinal cord ends as what
conus medullaris (L1-2) - where many nerves (Lumbar sacral) come out
Filum terminale internum
attaches cord to dural sac (S2)
attaches dural sac to coccyx
Cauda Equina
horse tail
Traveling spinal nerves
Descend to exit below associated vertebra
spinal cord grey and white matter
eye
grey internal butterfly
white outer segment
White Matter of the spinal cord
Axons – tracts/columns
Tracts extend into or from brainstem
Gray Matter of the spinal cord (D, I, V)
DAVE
Cell bodies/synapses – nuclei
dorsal horn/intermediate/ventral horn
Meninges surround the cord
DAP
Pia, arachnoid, dura mater/dural sac
Inside DAP is cerebral spinal fluid
are there any cranial nerves in the spinal cord
No cranial nerves
Spinal cord provides segmental info
• Info that comes into that level has to do w/ that level
• Motor and sensory
• Goes out to certain segment of body
Dorsal ramus:
smaller, innervates deep muscles and skin of back/posterior neck and head
Ventral ramus:
larger, makes up plexuses to extremities
Combine to form plexus and peripheral nerves
Ventral rootlets/root
motor efferents, outgoing information
Dorsal rootlets/root
sensory afferents, incoming information
Cervical Spinal nerves
Exit above vertebra (C1-C7), C8 b/w C7-T1
Provides segmental information re: UE’s (brachial plexus)
Thoracic, lumbar, and sacral spinal nerves
Exit below vertebra & provides segmental info
Provides segmental info re: LE’s (lumbar plexus) & bladder/sphincter (sacral plexus)
Disc bulge/herniation/foramen narrowing
Root compression
Spinal nerve compression
- Disc can impact the root or nerve
- Root compression - something is compressing the root
dermatomes
an area of skin supplied by sensory neurons that arise from a spinal nerve ganglion
learning pattered associate w/ dorsal root or spinal nerve
C2 dermatone
remainder of head
C5-T1 dermatones
UE
T4 derma
at nipple line
T10 derma
at umbilicus
L1-S2 derma
LE
a lesion to a single root level
may result in a DECREASE in sensation but not a COMPLETE LOSS.
myotome
Anterior root/spinal nerve contribute to multiple peripheral nerves, innervating multiple muscles that form the myotome.
C5 myotome.
Weakness to bicep and deltoid
Sensory deficit to upper lateral arm
Decreased biceps reflex
C6 myotome
Weak wrist extensors, biceps
Sensory deficit to thumb/index finger
18% of cervical radiculopathies
C7 myotome
Weak triceps, thumb extension
Sensory deficit to middle finger
Decreased triceps reflex
46% of cervical radiculopathies
L4 myotome
Weak DF, iliopsoas, quads
Sensory deficit to knee and medial shin
Decreased patellar tendon reflex
L5 myotome
Weak big toe extension and ankle DF
Sensory deficit to top of foot and big toe
40% of lumbosacral radiculopathies
S1 myotome
Weak ankle PF
Sensory deficit to little toe and lateral foot
Decreased Achilles reflex
45-50% of lumbosacral radiculopathies
how are peripheral nerves formed
Anterior rami from spinal nerves merge with one or more rami to form a plexus (network) that give rise to multisegmental peripheral nerves that innervate a muscle
UMN
Upper motor neuron is that neuron that has direct communication with the cortex
Lower motor neuron
Lower motor neuron is that neuron that has communication with muscle/end organ
UMN lesion
Lesion of connection to cerebral hemisphere
LMN lesion
Lesion of connection to muscle
UMN lesion signs and symptoms
Altered motor activity
Spasticity (hypertonicity)
Hyper-reflexia
Positive Babinski sign
Toes up-going and flared
LMN lesion signs and symptoms
Altered motor activity
Flaccid paralysis (hypotonicity)
Hypo-reflexia/areflexia
Muscle fasciculations
Muscle fasciculations
small, rapid, involuntary contractions in that are too weak to move a limb
muscle twitch
