Neuro Peer Tute test Flashcards
What structure has the function of initiation of appropriate / inhibition of inappropriate movements?
Basal ganglia
Which structure receives proprioceptive input and uses it to fine-tune skilled movements?
The cerebellum
Which structures are involved in motor memory?
Cerebellum & basal ganglia
What can be the result of basal ganglia damage?
Rigidity
Resting tremor
Uncontrolled jerky movements
What structure is the major sensory relay to the cortex?
The thalamus
What structure produces the CSF?
Choroid plexus in the ventricles
What structures allow outflow of CSF into the sinuses?
Arachnoid granulations
Where are the interventricular foramina? And what is it aka?
Foramina of Monro
Channels that connect the lateral ventricles with the 3rd ventricle
Where is the cerebral aqeduct?
Connecting the 3rd ventricle to the 4th
Where is the foramen of Magendie?
On the dorsal side of the 4th ventricle, it allows CSF to drain into the “cisterna magna” below the cerebelloum
Where are the foramina of Luschka?
Also draining out from the 4th ventricle
What does communicating hydrocephalus mean?
CSF is blocked after leaving the ventricles - but it can still communicate freely between the ventricles
What is non-communicating hydrocephalus?
Aka obstructive
CSF is blocked along one of the passages that connect the ventricles
What is Nissl substance & where is it found?
RER of neurons, which stains intensely purple in H&E (due to concentration of RNA)
What are the glial cells of the CNS that myelinate called?
Oligodendrocytes
Do oligodendrocytes myelinate one cell or multiple cells? What about Schwann cells?
Multiple
Schwann cells myelinate single neurons.
Which glial cells are important in the BBB?
Astrocytes
Which are more numerous in the CNS - neurons or glial cells?
Glial cells
What are the three major classes of brain herniation?
Uncal/transtentorial
Cingulate/subfalcine
Tonsillar/cerebellar
What symptoms tend to accompany all herniations? (5)
Headache Nausea Vomiting Blurred vision Papilloedema
What is papiloedema?
Blurring of the optic disc margins
What are differentiating symptoms of an uncal hernia?
LOC - via compression of RAS
Hemiparesis - via compression of corticospinal tracts
Mydriasis - via CNIII compression
(Also risk of PCA compression)
What artery can be affected by a cingulate hernia?
ACA
What are the effects of tonsillar hernias?
Life threatening compression of medulla, - incl CV & resp centres
What causes watershed strokes?
Systemic hypoperusion
What would you see on a brain that has had watershed stroke?
Multifocal lesions at the far boundaries of the cerebral arterial terriories
What colour are cerebral infacts?
They can be pale, or haemorrhagic (due to secondary transformation)
What happens to an infarct if the pt survives?
Glial scar formation and cystic fluid filled holes
What is the most likely cause of a large cortical stroke?
Amyloid angiopathy
What is the most common cause of subcortical strokes?
Hyalinearteriolosclerosis
What defines cerebral dominance?
The side of the brain involved in language
Right handed people are usually ____ dominant
Left
Left handed people are usually _____ dominant
Left
What proportion of right handed people are left dominant?
90%
What proportion of left handed people are left dominant?
70%
What do non-dominant hemisphere do?
Visual-spacial orientation
What part of the brain is largely responsible for executive function?
PFC
What part of the brain is essential for working memory?
DLPFC
dorso-lateral prefrontal cortex
Which part of the brain inhibits innapropriate behaviour?
Orbitofrontal
What part of the brain is important for motivation and emotion processing?
MPFC
Which division of the MCA supplies Broca’s area?
Superior
Which devision of the MCA supplies Wernicke’s area?
Inferior
Which aphasia tends to have associated muscle weakness & what does it have?
Broca’s
Contralateral face & UL hemiparesis
What sort of sensory deficit might you expect alongside a Broca’s aphasia?
Decreased sensation in contralateral face & upper limb
What sort of sensory deficit might you expect alongside a Wenicke’s aphasia?
R quadrantopia
As the temporal fibres of the left brain are for the upper R side.
What is Broca’s aphasia is also known as?
Productive aphasia
What is Wernicke’s aphasia aka?
Receptive aphasia
What is the 1st manifestation of frontotemportal dementia?
Behavioural and personality changes
impulsivity, anhedonia, apathy
What is the 1st presentation of Alzheimers?
Decrease in memory
dysnomia and circumlacutory language
What’s the 1st presentation of vascular dementia?
It depends on lesion sites - no pattern
What is the pattern that would help you distinguish vascular dementia?
Stepwise progression
What usually causes subdural haematomas?
Acceleration-decelleration forces tearing the bridging veins
What usually causes extradural haematomas?
Head trauma especially skull fracture rupturing the meningeal arteries
What usually causes subarachnoid haematomas?
Aneurism rupture
What does an extradural haematoma look like?
Tends to be lenticular in shape as the dura is strong and attached at the fissures
What does a subdural haematoma look like?
Tends to fill in the sulci
Which haematoma bleeds slowly and may not even present?
Subdural - as it’s venous pressure
Which spinal segment has no ANS p’way originating from it?
Cervical
What is the only certain way to distinguish sympathetic NS from parasymp NS?
Anatomy
Symp comes from thoracolumbar
Parasymp comes from craniosacral
Symp vs parasymp: Which usually has longer pre-ganglionic fibres?
Parasympathetic
Symp vs parasymp: Which usually has shorter pre-ganglionic fibres?
Sympathetic
Think of the sympathetic trunk
Symp vs parasymp: Which usually has longer post-ganglionic fibres?
Sympathetic
Symp vs parasymp: Which usually has shorter post-ganglionic fibres?
Parasympathetic
What does “divergence’ refer to?
The ratio of pre- to post-ganglionic fibres
Symp vs parasymp: Which has greated divergence?
Sympathetic
Symp vs parasymp: Which has ACh from pre-ganglionic receptors acting on NicR post-synaptically?
Both!
Symp vs parasymp: Which releases ACh from post-ganglionic neurons acring on MuscR on the tissue?
Both!
All parasympathetic ones, and sympathetic ones do in some circumstances (like it’s activation of sweat glands)
What is Horner syndrome?
Unilateral damage to the sympathetic trunk
What are the symptoms of Horner syndrome?
Ipsilateral ptosis
Ipsilateral miosis
Ipsilateral adiaphoresis
What is ptosis?
Drooped eyelid
What is miosis?
Constricted pupid
What id mydriasis?
Dilated pupil
What is diaphoresis?
Excessive sweating
What is adiaphoresis?
& what is it aka?
Decreased sweating
aka anhidrosis
CNS vs PSN: in which is neural regeneration poorer?
CNS
List 4 reasons CNS regeneration is poorer than PNS
CNS structure/cellularity is complex
Glial scar inhibits CNS regeneration
Neuronal degeneration is slower in CNS, and debris inhibits growth
Oligodendrocytes inhibit axon regrowth (cf Schwann cells)
What is the somatotopy of the spinal cord?
In the ventral horns, proximal muscles are represented medially, and distal muscles are represented laterally
Do the medial decending pathways of the spinal cord have bilateral or unilateral innervation of proximal muscles?
Bilateral
Do the lateral decending pathways of the spinal cord have bilateral or unilateral innervation of the distal muscles?
Unilateral
Medial or lateral descending pathways: which are important for balance?
Medial
LMN signs (5)
Flaccid weakness Hyporeflexia Signs of denervation Decreased tone Downgoing plantar reflex
What are 3 signs of denervation?
Atrophy
Fascivulations
Fibrillations
UMN signs?
Spastic weakness Hyperreflexia (+/- clonus) No signs of denervation Increased tone Positive Babinsky (upgoing)
What does an upgoing plantar reflex indicate?
UMN sign
Indicates lesion above level of L5/S1 (as these are the efferent motor responses)
In which lobe does Broca’s area lie?
Frontal
In which lobe does Wernicke’s area lie?
Temporal
some texbooks say parietal
Aphasias usually result from damage to which hemisphere?
Left
What is the corticobulbar tract?
The UMN tract for all non-ocular cranial nerve nuclei
What non-ocular, motor nuclei does the corticubulbar tract from one side supply? (bi-, uni-, ipsi-, contra-)
Bilateral for all of them, except for the lower face and tongue - where ennervation is unilateral (contralateral)
What will result from a right UMN lesion of CNVII?
Weak bottom half of left face
What will result from a right LMN lesion of CNVII
This is just facial nerve palsy - entire right side will be weak.
Which are the nerves that only have contralateral UMN supply from the corticobulbar tract?
VII Facial
VXII Hypoglossal
What does decerebrate posture exhibit?
Extension of lower & upper limbs
What does decorticate posture exhibit?
Extension of lower limbs
Flexion of upper limbs
Where much the lesion be to cause decerebrate posture?
Below the level of the red nucleus
Where is the red nucleus located?
In the rostral midbrain
Where must the lesion be to cause decorticate posture?
Above the level of the red nucleus
What does the red nucleus have to do with decorticate vs decerebrate?
It’s important for limb flexion - when it’s knocked out, everything goes into extension
(decerebrate)
When the control of it is lost the limbs go to their “default” (decorticate)
What is the likely cause of sudden, severe, unexplained headache?
Berry aneurism rupture
Where in the cerebral circulation do berry aneurisms tend to form?
On the circle of Willis
What results from a berry aneurism rupture?
Subarachnoid haemorrhage
Is the intraction between basal ganglia and cortex ipsi- or contralateral?
Ipsilateral
The basal ganglia regulate movement on the ___‘lateral side
Contralateral
The cerebellum interacts with the cortex on it’s ____‘lateral side?
Contralateral
The cerebellum fine-tunes movements in ___‘lateral limbs
Ipsilateral
What’s the likely cause of a R homonumous hemianopia with macular sparing?
L PCA infarct
as left brain see’s right field; and macular has colateral flow from MCA
What is the afferent nerve of the pupillary reflex?
CNII
Optic
What is the efferent nerve of the pupillary reflex?
CNIII
Occulomotor
What part of the brainstem is tested by the puillary reflex?
Midbrain
What is the afferent nerve of the corneal reflex?
CNV
Trigeminal
What is the efferent nerve of the corneal reflex?
CNVII
Facial
What part of the brainstem is tested by the corneal reflex?
Pons
What is the afferent nerve of the gag reflex?
CNIX
Glossopharyngeal
What is the efferent nerve of the gag reflex?
CNX
Vagus
What part of the brainstem is tested by the gag reflex?
Medulla
What’s the main motor pathway?
Corticospinal tract
Superficial vs deep mechanoreceptors: which has a smaller receptive field?
Superficial
Superficial vs deep mechanoreceptors: which are present in greater density?
Superficial
Which are the superficial recepters?
Meissner & Merkel
are outer Most
What structure is largely responsible for consciousness?
Reticular activating system
Where is the reticular activating system located?
Midbrain
Where are the cardio & resp centres located?
Medulla
What information is carried by the dorsal column medial lemniscus system?
Fine touch, vibration and propioception
On what side of the spinal cord does information in the DCML travel?
Ipsilateral to the stimulus
What are the two components of the DCML?
Cuneate & gracile
Cuneate vs gracile: which carries touch information from the lower limb?
Gracile
Cuneate vs gracile: which carries touch info from the upper limb?
Cuneate
Cuneate vs gracile: which runs more medially?
Gracile
Cuneate vs gracile: which runs more laterally?
Cuneate
Where does the DCML synapse?
Thalamus
In the spinal cord, sensory information is carried on which side?
Dorsal
In the spinal cord, motor information is carried on which side?
Ventral
In the brainstem, CN motor nuclei are found on which side?
Medial
In the brainstem, CN sensory nuclei are found on which side?
Lateral
Which nucleus provides the branchial motor ourput for CN IX (glossoph’) and X (vagus)?
Nucleus ambiguous
Which nucleus receives gustatory and visceral sensory input from CN VII, IX and X?
Nucleus tractus solitarius
Which nucleus provides the motor output for CN VII?
Facial motor nucleus
Which nucleus provides the preganglionic parasympathetic output on CN III?
Edger-Westphal nucleus
Taste from the anterior 2/3 of the tongue travels in which CN?
Chora tympani of CN VII
Touch sensation from the anterior 2/3 of the tongue travels in which CN?
Lingual nerve - a branch of V3
Taste from the posterior of the tongue travels in which CN?
Glossopharyngeal (IX)
Touch sensation from the posterior of the tongue travels in which CN?
Glossopharyngeal (IX)
When the eye is looking pointed laterally, what muscle & nerve is being tested?
Lateral rectus CN IV (abducens)
When the eye is pointed supero-laterally, what muscle & nerve is being tested?
Superior rectus
CN III
When the eye is pointed supero-medially, what muscle & nerve is being tested?
Inferior oblique
CN III
When the eye is pointed medially, what muscle and nerve is being tested?
Medial rectus
CN III
When the eye is pointed inferomedially, which muscle and nerve is being tested?
Superior oblique CN IV (trochlear)
When the eye is pointed infero-laterally, which muscle and nerve is being tested?
Inferior rectus
CN III
Which 4 muscles of eye movement does CN III ennervate?
Medial rectus
Inferior oblique
Superior rectus
Inferior rectus
Which muscle of eye movement does CN IV ennervate?
Superior oblique
Which muscles of eye movement does CN VI ennervate?
Lateral rectus
the abducens abducts
Which is the muscle that changes the curvature of the lens?
Ciliary muscle
What does contraction of the ciliary muscle do to the shape of the lens?
It lets it “boing” back to its rounder shape (able to focus on things nearby)
What is the intermediate structure that lets the lens relax when the ciliary muscle contracts?
Zonules
