Notes from rest of Ballyk's lectures Flashcards
What is present in the epidural space?
- FAT
2. Blood vessels
The dorsal and ventral roots exit via which sulci?
- Dorsolateral and ventrolateral sulci
What do the lumbosacral and cervical enlargements contain
- Cervical (C5-t1) contain somatic motor to arms
2. Lumbar (L2- S3) contain somatic motor to legs
What do the IML columns contain (T1-L2)?
What do they contain between S2-S4?
Cell bodies of sympathetic preganglionic Ns
Cell bodies of Parasympathetic pre gang Ns
Location of IML cell columns?
T1- L2, S2-S4
Neurons of ventral horns are…
Neurons of IML cell columns are…
- Somatic motor
2. Visceral motor
What parts of the thalamus relay information from basal ganglia?
from cerebellum?
from skin,muscle, joints?
- Both VA and VL nuclei
- VL nucleus
- VP nucleus
What are the functions of the limbic system?
- Olfaction
- Survival
- memory
- behavior
What type of movement are the medial portions of the ventral horns responsible for?
Ipsilateral
axial muscle
(Posture and balance)
What type of movement are the lateral expansions in the cervical and lumbar regions responsible for?
Ipsilateral
Limb muscles - skilled Voluntary movement
List which spinal levels are tested in the following reflexes
- Biceps
- Triceps
- Patellar
- Achilles
- C6
- C7
- L4
- S1
LMN lesion will result in …. 5 things
- Ipsilateral weakness
- HYPOreflexia
- FLACCID paralysis
- Atrophy
- Fasciulations
UMN lesions will result in… 5 things
- Hemiplegia (depends on level)
- HyPER reflexia
- No atrophy
- No fasciculations
- BABINSKI
In a unilateral lesion to mandibular nerve (5) - bilaterally innervated - how does the jaw swing?
Towards the weak side
Which axon decussates in SS from body and face?
The second order neurone decussates
Where is the cell body of the first order neuron?
GANGLION IN PNS
- Body (dorsal root ganglion)
- Face (trigeminal ganglion)
Where is the cell body of the second order neuron?
- Dorsal horn of spinal cord
2. Brainstem nucleus
List 4 most medial voluntary motor nuclei (LMNs)
(3) Occulomotor
(4) Trochlear
(6) Abducens
(12) Hypoglossal
list 4 lateral voluntary motor nuclei (LMNs)
(5) The Masticator nucleus
(7) The facial nucleus
(9,10) Nucleus ambiguous
(11) Accessory
List 4 Visceral Motor nuclei (Contain PREGANGLIONIC Psy Ns)
(3) Edinger Westphal
(7) Superior salivatory - everything that drips except the parotid
(9) Inferior salivatory (Parotid)
(10) Dorsal Vagal (Thoracic and abdominal viscera)
List the two Somatic Sensory nuclei (Second order sensory neurons)
- Spinal trigeminal nucleus
2. Pontine trigeminal nucleus
List the two special sensory nuclei (Second order sensory neurons)
- The vestibular (8) - BALANCE
2. The cochlear (8) - Auditory
In a supratentorial lesion, what are the symptoms of increased ICP
Effects are contra or ipsilateral?
- Headache
- Altered mental status
- Nausea, vomiting
- Papilledema,
- Diplopia
EFFECTS ARE CONTRALATERAL FACE AND BODY
What creates the blood-ISF barrier
Astrocytic end feet - induce formation of Tight Junctions between endothelial cells of Cerebral BVs
What forms the Blood-CSF barrier?
The choroid plexus
Where do cerebral BVs form continuous capillaries?
Fenestrated capillaries?
- Continuous everywhere EXCEPT
2. In the choroid plexus
Choroid ependymal cells are joined by
TIGHT JUNCTIONS
Function of the choroid ependymal cells?
Secrete CSF
Total volume of CSF:
Rate of production of CSF:
- Volume = 140mls
2. 500ml/day produced
How do you differentiate a block in CSF movement versus impaired absorption?
- block in movement - only some of the ventricles will enlarge depending on block
- All ventricles enlarge - due to a genesis of villi
Met-HB (subacute blood) appears
BRIGHT on both T1 and t2
Hemosiderin
Appears DARK on T1 and T2
Most pathologies are ….. on T1… and ….. on T2
DARK on T1
BRIGHT on T2
except for fat, calcium, melanin, blood at certain stages
BEST modality for imaging an acute stroke
CT scan of head with no contrast - rule out contraindications
high attenuation clot/embolus can often be seen
BEST modality for imaging an acute stroke if in the posterior fossa
MRI - diffusion weighted - water restriction (first 7-10 days)
To image blood vessels you can use
Doppler - flowing blood hypo echoic, dense tissue hyper echoic - challenging for vertebral circulation
cT angio
MR Angio
What is the order of the neurological exam?
1 Mental status
- Cranial nerves
- Motor
- Sensory
- coordination
- Stance and Gait
The receptors for tactile sensation are…
LOW threshold mechanoreceptors
Nociception receptors are…
HIGH threshold mechanoreceptors
Which receptors detect onset and end of stimulus?
RAPIDly acting receptors
Which receptors detect high frequency vibration?
RAPIDLY acting receptors
Which receptors report continuously on a stimulus?
Slow adapting receptors
Which receptors are good for reporting pressure, shape, LOW frequency vibration?
SLOW adapting receptors
Which are the only unmyelinated fibers?
cLASS C… they are also smallest in diameter and conduction velocity
Capacitance and velocity are
Inversely correlated
Which nerve fibers have motor and sensory targets?
Aalpha
A gamma
B
C
Which class of fibers is used for Limb position
and Motion - muscle spindle
MOTOR - EXTRAfusal
Class A alpha
Which class of fibers is used for Skin, conscious proprioception, touch, pressure, vibration and 1B AFFERENT GOLGI tendon tension
Class A beta
Which class is for FAST pain, cold, and hair follicles
Class A delta
Which class of fibers is for SLOW pain, warmth, - has autonomic post-ganglionic fibers - grey rami
Class C
Class B fibers are
for Preganglionic autonomic, white rami
Where do the sensory relay neurons project
- To neurons in the dorsal horn to suppress the pain pathway
- to medullary and pontine reticular formations for alerting responses and modifying locomotor reflexes
- Superior colliculus to drive orientation
AT THE first synapse what type of inhibition do you have/
- Cortical descending inhibition
2. Lateral inhibition to sharpen localization of the stimulus
What is the function of the secondary somatosensory area? S2?
Receives signals from S1 and thalamus
Important for tactile memory
Function of the Sensory association area?
Visual and somatosensory signals integrated
Pitch is proportional to
Frequency (Hz)
Intensity of sound is
Difference in pressure between compressed and rarefied patches of air - decibels, amplitude variation
Movement of the ossicles is modulated by 2 muscles
Tensor tympani (V3)
Stapedius (7)
lesions there can result in hyperacusis
The tympanic cavity is connected to 2 things
- Nasopharynx (via ET)
2. Mastoid air cells (via lots of channels)
The 2 special sense organs in the inner ear are
- Vestibular apparatus : senses equilibrium
2. Cochlea - senses sound
The scala vestibuli and scala tymapni both contain
Perilymph
The membranous labyrinth contains
Endolymph - lots of K+
The width of the basilar membrane is determined by
SIZE of the spiral lamina (INVERSELY)
Where is the basilar membrane the widest?
AT THE APEX (narrow and stiff at the base)
What is the name of the area through which the scala vestibuli and scala tympani are continuous?
At the Helicotrema
WHich scala does the oval window fit into and what does it do
The Scala Vestibuli
- INITIATES pressure waves
what does the round window do and where does it fit?
The scala tympani
- RELIEVES pressure waves
What part of the inner ear contains the auditory receptor cells and what do they do?
Organ of Corti - converts sound energy into Action potentials
Where is the frequency the lowest for the basilar membrane tonotopy?
AT THE APEX (higher frequency at the bASE)
The stereocilia of which hair cells extend INTO the Tectorial membrane?
The stereo cilia of the Inner hair cells
The longest or tallest hair cells are closer or further away from the modiolus?
They are furthest away
When the basilar membrane moves up what happens to the stereo cilia (1) and to the hair cells (2)
1) The stereo cilia move OUT
2) The hair cells MOVE IN
What is the receptor potential like when the stereo cilia bend towards the tallest hair cell?
Depolarizing potential (towarD... Depolarize) - INCREASED K+ channel conductivity INCREASE NT release at the base along spiral ganglion
What is the receptor potential like when the stereo cilia bend away from the tallest hair cell?
Away… Hyper polarize
DECREASED K+ channel conductivity
Which ion is the main driving force for receptor potentials in hair cells?
K+
What is the function of the IHCs
Conduct auditory input by cochlear nerve
What is the function of the OHCs
Amplify Basilar membrane movement (100X) during low intensity (low amplitude sound)
When can you have deafness happening at what level?
At the cochlear nerve, damage to ear, or cochlear nucleus
ABOVE that all are bilaterally pathways
