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