Week 2 Flashcards
What are the two connected sources of arterial blood for the brain?
Ant. and post. circulation
What vessel supplies the anterior circulation of the brain?
Int. Carotid a.
What does the Anterior circulation of the brain supply with blood?
Ant. 3/5 of cerebrum
Diencephalon
Int. capsule
What are the 3 main branches of the Int. Carotid a.?
Middle cerebral a.
Ant. cerebral a.
Perforating branches
What is an Endarterectomy?
Removal of plaque from an artery
What vessel supplies the posterior circulation of the brain?
Vertebrobasilar a.
What does the Posterior circulation of the brain supply with blood?
Brainstem
Cerebellum
Post. 2/5 of cerebrum
Diencephalon
What are the main branches of the Vertebrobasilar a.?
Cerebellar (PICA, AICA, SCA)
Pontine
Post. cerebral
Striate & thalamic branches
What vessels supply the Midbrain?
-Post. Cerebral-
post. communicating
sup. cerebellar
What vessels supply the Pons?
-Basilar-
ant. inf. cerebellar (AICA)
What vessels supply the Medulla?
-Ant. Spinal-
post. spinal
ant. + post. inf cerebellar (AICA, PICA)
What rate will the brain try to keep the blood flow at?
50 ml/min
What happens if the blood pressure in the brain drops below 50 mmHg?
The blood vessel will try to dilate, but due to lack of pressure keeping it open, it will collapse. This leads to Ischemia
What happens if the blood pressure in the brain raises above 150 mmHg?
The blood vessel will dilate to try and reduce blood pressure leading to high bp and high volume. This leads to Vasogenic Oedema
What is Steal syndrome
If patient has stenosis in subclavian a. before it branches to vertebral a. the limb, if used excessively, will not get enough blood from subclavian a. alone. Therefore blood that would go to the brain via the vertebral a. is instead taken to the limb, depriving the brain of blood
What are the symptoms of a Stroke?
Facial asymmetry
Speech disturbance (dysphasia)
Asymmetrical weakness in muscles
What is a Stoke?
Loss of neurological function due to impaired blood supply to brain
What is the difference between a Stroke and a Transient ischemic attack (TIA)?
In a Stroke the symptoms must last longer than 24 hrs or lead to death with no apparent cause other than that of vascular origin
What are the 3 types of Stokes?
Ischemic (80%)
Haemorrhagic (15%)
Subarachnoid haemorrhage (5%)
What are the 3 main causes of a Haemorrhagic stroke?
HT, Tumour, Bleeding disorder (or blood thinners ie. warfarin)
What are the primary brain damages of a haemorrhagic stroke?
Mechanical damage associated with the mass effect, within minutes to hours of bleeding onset
What are the secondary brain damages of a haemorrhagic stroke?
Surrounding oedema, oxidative stress, comorbidities ie. age
What is the main causes of Ischemic strokes?
Cardio-Embolisms (clots)
Small vessel disease (diabetes)
What happens in lacunar stroke?
Type of ischemic stroke where lacunar striate arteries are blocked leading to necrosis that forms small cavities in the brain
What is the Prenumbra?
The last salvageable part of the brain in the event of a stroke
What issue may often “imitate” stoke?
Hyperglycaemia (diabetes)
What are the 4 classifications of stroke according to Oxford Community Stroke Project (OCSP)?
Total ant. circulation syndrome (TACS)
Partial ant. circulation syndrome (PACS)
Lacunar syndrome (LACS)
Post. circulation syndrome (POCS)
What are symptoms associated with OCSP’s Total ant. circulation syndrome?
Hemiparesis & dysphasia & homonymous hemianopia (loss of the same half of vision in both eyes)
What are symptoms associated with OCSP’s Partial ant. circulation syndrome?
Isolated higher cortical dysfunction OR any two of: hemiparesis, higher cortical dysfunction, hemianopia
What are symptoms associated with OCSP’s Post. circulation syndrome?
Isolated hemianopia, brainstem or cerebellar syndromes
What are symptoms associated with OCSP’s Lacunar syndrome?
Pure motor stroke OR
Pure sensory stroke OR
Sensorimotor stroke OR
Ataxic hemiparesis OR
Clumsy hand-dysarthria
What are three goals for immediate treatment for Stroke?
Consider for Thrombolysis
Supplement O2 if sats below 95% and no contraindication
Aim for 5-15 mmol/litre blood Glucose
What would be given to a patient 24hrs after thrombolysis for ischemic stoke?
Antiplatelets ie. aspirin 300 mg for 2 weeks
What would be used for secondary prevention of Stokes?
Antiplatelet/Anticoagulant
Lifestyle factors
High intensity statin
BP-lowering therapy
What is the function of the Corticobulbar tracts?
Carries UMN input to motor nuclei of Trigeminal (V), Facial (VII), Glossopharyngeal (IX), Vagus (X), Accessory (XI), and Hypoglossal (XII) nerves
How does the Corticobulbar tracts innervate?
Bilaterally
What is the function of the Rubrospinal tract?
Effects changes directed by the cerebellum in upper limb flexion
What structure does the Rubrospinal tract originate from?
Red nucleus
What is the function of the Tectospinal pathway?
Links visual stimuli with neck and head movements allowing visual stability and focus on a given target
What structure does the Tectospinal pathway originate from?
Superior Colliculus
What is the function of the Vestibulospinal pathway?
Provide control over anti-gravity muscles and processes to protect head during unexpected posture changes
What structure does the Vestibulospinal pathway originate from?
Lateral + Medial vestibular nuc.
Lat. ipsilateral excitatory to extensors, inhibitory to flexors
Med. bilateral to neck muscles
What is the function of the Reticulospinal pathway?
Links emotion to posture and enhance the response to stimuli (primes upper body for fight or flight)
What structure does the Reticulospinal pathway originate from?
Pontine and Medullary reticular formation
Descends ipsilaterally with bilateral innervation in cervical spinal cord
What would be symptoms of a brainstem lesion in the medial lemniscal pathway?
Contralateral loss of JPS and discriminative touch
What is the Spinal lemnicscal pathway?
An extension of the Spinothalamic tract through the brainstem (carries pain + temp)
What would be symptoms of a brainstem lesion in the Spinal lemniscal pathway?
Contralateral loss of pain + temp sensation
Where in the brain is the Reticulum found?
Central Tegmentum
What is the combination of the sup. and inf. colliculi called?
Tectum
Cranial Nerve I
Olfactory - Olfaction
Cranial Nerve II
Optic - Vision
Cranial Nerve III
Oculomotor - Eye, pupil, lens movement
Cranial Nerve IV
Trochlear - Enables movement of eye’s superior oblique muscle (rotates eye down)
Cranial Nerve V
Trigeminal - Provides sensory and motor innervation to muscles of mastication
Cranial Nerve VI
Abducens - Control movement of lateral rectus muscle (lateral eye movement)
Cranial Nerve VII
Facial - Motor innervation for muscles for facial expression, parasymp innervation for lacrimal gland and salivary glands, and sensory innervation for ant 2/3 of tongue
Cranial Nerve VIII
Vestibulocochlear - Hearing and balance
Cranial Nerve IX
Glossopharyngeal - Speech, swallowing, salivation (parotid), BP (carotid sinus), blood gases (carotid body), taste post 1/3, sensory data from tongue + ear
Cranial Nerve X
Vagus - Speech, swallowing, heart rate, stomach motility, abdom and thoracic visceral sensation, BP (aortic arch), blood gases (aortic body), taste, sensory data from tongue + ear
Cranial Nerve XI
Accessory - Head movement (traps, sternocleidomastoid)
Cranial Nerve XII
Hypoglossal - Tongue movement
Function of Nucleus Ambiguus?
Contains CN’s IX and X
Controls motor function of pharynx and larynx
Function of Sup. Salivatory nuc.?
Contains CN VII
Control of lacrimal, sublingual and submandibular glands (salivary glands)
Function of Inf. Salivatory n.?
Contains CN IX
Control of parotid gland
Function of Trigeminal mesencephalic n.?
CN V
Proprioception from the mouth
Function of Trigeminal pontine n.?
CN V
Discriminating touch from face
Function of Solitary n.?
CN’s VII, IX, X
Carotid baroreceptors & visceral afferent from pharynx, larynx, lungs, gut
What are the 7 neuron modalities from medial to lateral?
GSE, GVE, SVE, GVA, SVA, GSA, SSA
General Somatic Efferent (GSE) nuclei contains what CN’s?
III, IV, VI and XII
Special Visceral Efferent (SVE) nuclei contains what CN’s?
V, VII, IX, X and XI
General Visceral Efferent (GVE) nuclei contains what CN’s?
III, VII, IX and X
What special nuclei are within the General Somatic Efferent (GSE) nucleus?
Oculomotor nuc.
Trochlear nuc.
Abducens nuc.
Hypoglossal nuc.
What special nuclei are within the Special Visceral Efferent (SVE) nucleus?
Trigeminal motor nuc.
Facial motor nuc.
nuc. Ambiguus
What special nuclei are found within the General Visceral Efferent (GVE) nucleus?
Edinger-Westphal nuc.
sup. & inf. salivatory nuc.
Dorsal motor nuc. of Vagus
General Visceral Afferent (GVA) nuclei contains what CN’s?
IX and X
What special nuclei are within the General Visceral Afferent (GVA) nucleus?
nuc. Solitarius
General Somatic Afferent (GSA) nuclei contains what CN’s?
V
(VII, IX and X)
Special Somatic Afferent (SSA) nucleus contains what CN’s?
II and VIII
Special Visceral Afferent (SVA) nucleus contains what CN’s?
I, VII, IX and X
What special nuclei are within the General Somatic Afferent (GSA) nucleus?
Trigeminal mesenchephalic nuc.
Trigeminal principal nuc.
Trigeminal spinal nuc.
What special nuclei are within the Special Somatic Afferent (SSA) nucleus?
Vestibulocochlear nuc.
What special nuclei are within the Special Visceral Afferent (SVA) Nucleus?
nuc. Solitarius
Function of Medial geniculate?
Relay auditory stimuli to cerebral cortex
Function of Red nucleus
Motor co-ordination
Function of Substantia nigra
Motor modulation
Function of sup. Colliculus
Co-ordinates eye movement in response to visual and other stimuli
Function of inf. Colliculus
Co-ordinates head and upper body movement in response to auditory stimuli
Function of Reticular formation
Consciousness & cortical arousal
Function of Pontine nuclei
Link between cerebral cortex and cerebellum
Function of Olive
Auditory control (sup.) and movement control (inf.)
Function of Vital centres
Regulate heart rate, breathing, blood vessel diameter
Function of non vital centres
Co-ordinate swallowing, vomiting, cough, sneezing, hiccupping
What structures are present in the medial part of the brainstem from dorsal to ventral?
Somatic motor nuclei
Medial longitudinal fasciculus (MLF)
Medial Lemniscus
Motor pathway (corticospinal)
What structures are present in the lateral part of the brainstem from dorsal to ventral?
Spino-cerebellar
Spino-thalamic
Somatic sensory nuclei
Sympathetic
Name all structures
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Name all structures
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What is a unique trait about the CN I?
It projects to the olfactory cortex BEFORE the thalamus unlike every other CN
What may cause Anosmia?
Olfactory neuropathy caused by upper resp tract infection
or
Trauma, causing movement of olfactory bulb causes nerves to tear
How do olfactory nerves regenerate?
Basal cells on the cribriform plate can differentiate into Bipolar (olfactory) neurons
What are the 4 nuclei of the Trigeminal n. and each of their purposes?
Mesencephalic (Proprioception)
Principal (Touch/Pressure)
Spinal (Pain)
Motor (Supply muscles of 1st pharyngeal arch)
What are the 3 divisions of the Trigeminal nerve, and are they sensory or motor?
Ophthalmic V1 (Sens)
Maxillary V2 (Sens)
Mandibular V3 (Sens + Motor)
What are the 3 main branches of the Ophthalmic n.?
Lacrimal
Frontal
Nasociliary
What is the function of the Lacrimal nerve?
Supplies general sensation to lacrimal gland, conjunctiva, and upper eyelid.
Also carries parasymp fibers of facial nerve (VII) to the lacrimal gland
What are the 2 divisions and function of the Frontal n.?
Divides into supra-orbital and supra-trochlear n.
Supplies the upper eyelid and conjunctiva, frontal sinus and the scalp as far back as vertex
What are the branches of the Nasociliary n.?
Gives off long ciliary nerve(s), ant + post ethmoidal nerves, before continuing as infratrochlear n.
What nerves are represented by the purple, blue and pink areas?
Ophthalmic, Maxillary, and Mandibular respectively
What 2 nerve branches does the maxillary n. send into the orbit and through what structure do they pass?
Zygomatic and Infra-orbital branches
Through the inferior orbital fissure
The infra-orbital nerve will then leave via the infra-orbital canal
What 2 branches does the maxillary nerve send to the palate and upper teeth?
Palatine and Sup. Alveolar branches
What are the main branches of the Mandibular n.?
Auriculotemporal
Masticatory
Lingual
Inferior Alveolar
What muscles does the motor root of the Mandibular n. supply?
Muscles of mastication:
Lat. pterygoid, med. pterygoid, masseter, and temporalis
How would you test for the Trigeminal nerves motor function?
Jaw Jerk
What is the path of the Ophthalmic n.?
Ophthalmic division > lat. wall of cavernous sinus > sup. orbital fissure > Orbit
What is the path of the Maxillary n.?
Maxillary division > lat. wall of cavernous sinus > foramen rotundum > pterygopalatine fossa
What is the path of the Mandibular n.?
Mandibular division > foramen ovale > infratemporal fossa
What is the path of the Oculomotor n.?
Passes between post and sup cerebral art. before lying close to post communicating art.
Runs anteriorly on lat. wall of cavernous sinus
What are the two main divisions of the Oculomotor n. and what structure do they pass through?
Sup. & Inf. Divisions
Will pass through common tendinous ring of Zinn
What does the Sup. division of the Oculomotor n. supply?
Levator palpebrae superioris & Superior rectus
What does the Inf. division of the Oculomotor n. supply?
Medial rectus, Inferior oblique, & inferior rectus
What is unique about CN IV?
It exits the brainstem from its POSTERIOR surface
What is the path of the Trochlear n.?
Runs anteriorly around cerebral peduncle > lat. wall of cavernous sinus > through sup. orbital fissure
What does the Trochlear nerve supply and what may be a consequence of damage to this n.?
Superior Oblique
Patient won’t be able to look inferior medially, diplopia when walking downstairs or reading book
What is the path of the Abducent n.?
Exit pons ant. > INSIDE of cavernous sinus > through superior orbital fissure
What does the Abducent n. supply and what would be the consequence of damage to this n.?
Lat. rectus
Injury to right (or left) n. would cause diplopia when looking right (or left) - the right (or left) eye would not fully abduct
What are the 2 main nuclei of the Facial Nerves?
Motor nuc. & nuc. Solitarius
What are the 2 divisions of the Facial Motor nuc. and what are their connections?
Sup. and Inf. divisions
Sup. connected to ipsilateral and contralateral motor cortices
Inf. connected to contralateral cortex ONLY
What is the path of the Facial n.?
Exits at cerebellopontine angle > enters internal acoustic meatus w/ cranial nerve VIII and labyrinthine art. > enters facial canal in temporal bone > exit through stylomastoid foramen
In the fascial n. the cell bodies for taste fibres are in what structure?
Geniculate ggl.
What are the 5 branches of the Facial n. from sup. to inf.?
Temporal
Zygomatic
Buccal
Marginal Mandibular
Cervical
Before the Facial nerve divides in the parotid gland it gives of what branch?
Post. Auricular n.
Branch to supply occipitalis and the auricular muscles
What would be the symptoms of damage to the Facial nerve at cerebellopontine angle?
-Balance and hearing problems
-Ipsilateral facial muscle paralysis
-Taste disturbances
-Reduced lacrimal secretions
What would be the symptoms of damage to the Facial nerve within the petrous temporal bone?
-Reduced lacrimal secretions
-Taste disturbances
-Ipsilateral facial muscle paralysis
What would be the symptoms of damage to the Facial nerve distal to the stylomastoid foramen?
-Ipsilateral facial muscle paralysis
-Dry eye, drooling
What is the difference between Central and Peripheral facial palsy?
Central in an UMN lesion and the person can raise eyebrows
Peripheral is a LMN lesion and person can’t raise eyebrows
Neither can blow cheeks
How would you test for Facial n. and Trigeminal n. function?
Cornea reflex
What are the motor and sensory nuclei of the Glossopharyngeal n.?
nuc. Ambiguus and nuc. Solitarius
What is one of the main branches of the Glossopharyngeal n.?
Tympanic branch
What are the motor and sensory nuclei of the Vagus n.?
nuc. Ambiguus & nuc. Solitarius
How do you do to test for Vagus n.?
Gag reflex
What is the main symptom of damage to the Hypoglossal n.?
Ipsilateral tongue weakness, leading to tongue deviating to the side of the lesion
What is Spina Bifida?
Congenital abnormality where there is incomplete closing of the spine and spinal cord membranes
Is a type of neural tube defect
Where is Spina bifida most common on the spine?
Lumbrosacral region
What are the types of Spina bifida from least to most severe?
Spina bifida occulta
Meningocele
Myelomeningocele
Myeloschisis
Describe Spina bifida occulta
“Open” spine but no structures actually move out of the gap
Describe Meningocele
Open neural arch with the meninges pushed outside the body to form sac, however the spinal cord itself stays in normal position
Describe Myelomeningocele
Open neural arch with meninges & spinal cord pushed outside the body to form sac
Describe Myeloschisis
Meningeal sac is open exposing CSF and spinal cord to external environment
What is the link between Myelomeningocele and Hydrocephalus?
80% of individuals with Myelomeningocele will have Hydrocephalus (caused by disruption of CSF drainage leading to increased volume of CSF)
In Myelomeningocele what will cause Hydrocephalus?
Hydrocephalus will be caused by Chiari 2 malformation where parts of the brain are pushed into the top of the spinal cord blocking normal flow of CSF and build up of fluid in brain
What is the Ventriculoperitoneal (VP) shunt?
Used to drain CSF into peritoneal space to maintain intracranial pressure.
If shunt is blocked it’s an emergency and surgery will be needed
Where may spina bifida be first picked up?
Ultrasound pregnancy scans
What are common symptoms of Neurogenic Bladder?
Urinary incontinence
Overactive bladder
Urinary retention
What are common symptoms of Neurogenic Bowel?
Constipation
Faecal incontinence
A lesion between what vertebral levels may impact sexual function and fertility?
T12 - S5
What are possible consequences of ANY level spinal cord injury?
Neurospasticity
Neuropathic Pain
What are the spinal levels of the Sympathetic ganglia?
Superior ggl. C1 - C4
Middle ggl. C5 - C6
Inferior ggl. C7 - C8
What is the combination of the Inferior Cervical ggl. and T1 called?
Stellate ggl.
What is the sympathetic pathway to dilate the eyes?
Sup. Cervical ggl. > Carotid plexus (cavernous sinus) > Nasociliary n. > Long ciliary n. (dilates eye)
What are the main signs of Horner’s Syndrome?
Ptosis (drooping of upper eyelid)
Miosis (pupillary constriction)
Anhydrosis (lack of sweating)
What causes Horner’s syndrome?
Disruption of sympathetic nerve supply to the eye(s)
What is another name for the Accessory Oculomotor nuc.?
Edinger-Westphall nuc.
What is the path of parasympathetic fibres within the Oculomotor n.?
They follow the oculomotor n. before following the inf. division to the Ciliary ggl. where they synapse, becoming the short ciliary nerves (dilate eye)
What is the path of the light reflex?
Optic Nerve picks up light and sends signal down to the Optic Tract. Some nerves will branch off and synapse in the Pretectal nucleus in the brainstem. Signals will then be sent to Edinger-Westphall nuc. that will then send parasympathetic impulses to the Oculomotor n. > Ciliary ggl. > short ciliary nerves, finally leading to pupillary restriction
What is Consensual Light Reflex and why does it work?
Even in light only goes to one eye, the other will also constrict.
Because Pretectal nuc. gives off nerves to both Edinger-Westphall nuclei (nerves pass through post commissure to cross over to other side of brain)
What would be the symptoms of damage to the Oculomotor n.?
Dilated pupil
Ptosis
Eye turn Laterally and Inferiorly
What CN supplies the Sup. Salivatory nuc.?
Facial VII
What is the path of parasympathetic nerves within the Facial n.?
Follow facial nerve through facial canal, exit at the Geniculate ggl. as the Greater Petrosal n. before merging with the Deep Petrosal n. in the foramen lacerum. Join to form Nerve of Pterygoid canal and synapse at Pterygopalatine ggl.
What is the path of Facial nerve parasympathetic fibres innervating the lacrimal gland?
Post ganglionic fibres leave the Pterygopalatine ggl. and travel within the Zygomatic n. (branch of Maxillary n. V2) before then leaving to travel within the Lacrimal n. (branch of ophthalmic n. V1)
What is the path of Facial nerve parasympathetic fibres innervating the submandibular and sublingual glands?
Branch off facial nerve as Chorda Tympani, travel within Lingual n. V1, leave to synapse at the Submandibular ggl.
What CN supplies the Inferior Salivatory Nucleus?
Glossopharyngeal IX
What is the path of the parasympathetic fibres of the Glossopharyngeal n. that innervate the Parotid gland?
Travel within the Tympanic n. before entering the tympanic cavity, then become the lesser Petrosal n. and enter the Otic ggl. where they synapse and emerge as the Auriculotemporal n.
What are the 4 main branches of the Maxillary n.?
Infra Orbital
Zygomatic
Sup. Alveolar
Palatine
Label diagram of Midbrain (sup. Colliculus)
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Label diagram of Midbrain (inf. Colliculus)
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Label diagram of Upper Pons
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Label diagram of Mid Pons
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Label diagram of Lower Pons
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Label diagram of Upper Medulla
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Label diagram of Mid Medulla
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Label diagram of Lower Medulla
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