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153 Cards in this Set
- Front
- Back
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Name the major types of cells in the CNS and PNS as well as their embryoligic origins.
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CNS:
1) Neurons - neuroectoderm 2) Astrocytes - neuroectoderm 3) Microglia - mesoderm 4) Oligodendrocytes - neuroectroderm 5) Ependymal cells - neuroectoderm PNS: 1) Neurons - neural crest 2) Schwann cells - neural crest "Microglia, like Macrophages, originate from Mesoderm" |
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What is the purpose of microglia?
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They are the CNS phagocytes
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What do astrocytes do?
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Physical support
Repair K+ metabolism Removal of excess neurotransmitter Maintenance of blood-brain barrier |
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What do oligodendocytes do?
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They myelinate multiple CNS axons - up to 30 each.
Remember - "oligo" means "a few", so each one myelinates more than one. |
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What do Schwann cells do?
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Each Schwann cell myelinates ONLY 1 PNS axon.
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What is the name of the rough endoplasmic reticulum that are in the neuron cell bodies?
What's the name of the stain that binds to them? Where are they not found in the cell? |
Nissl substance
Nissl stain They're not found in the axon hillock or in the axon |
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What is the neurotransmitter of preganglionic neurons?
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Acetylcholine
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What is the neurotransmitter of postganglionic sympathetic neurons?
What is the neurotransmitter of postganglionic parasympathetic neurons? |
Sympathetic: Norepi (except sweat glands and some blood vessels use ACh)
Parasympathetic: ACh |
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What do Pacinian corpuscles sense and where are they found?
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Vibration, pressure
Found in deep skin layers |
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Compare Merkel tactile disks to Meissner corpuscles.
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Merkel: Sense position, light, crude touch
Located in the basal layer of epidermis in glabrous (hairless) and hairy skin Unencapsulated Slow-adapting Meissner: Sense fine touch Located in the dermal papillae of glabrous (hairless) skin Encapsulated Fast-adapting |
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This neurotransmitter is increased in schizophrenics and depleted in Parkinson disease. What is it, what are the precursors in the pathway and where is it manufactured?
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Dopamine
Phenylalanine --> Tyrosine --> L-Dopa --> Dopamine --> Norepi --> Epi In the substantia nigra pars compacta Remember, too, that tyrosine is the precursor to MELANIN. |
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This neurotransmitter is increased in mania and low in depression and insomnia. What is it, what are the precursors in the pathway and where is it manufactured?
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5-HT (Serotonin)
Tryptophan - 5-Hydroxytryptophan --> 5-Hydroxytryptamine Made in the raphe nuclei of the brainstem |
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What is the major inhibitory neurotransmitter of the brain?
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GABA
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For movement control, the basal ganglia has 2 pathways, direct and indirect. Which one is the excitatory pathway and which one is inhibitory?
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Direct = Excitatory
Indirect = Inhibitory |
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What's the main difference between the direct and indirect pathways of the basal ganglia?
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Direct = excitatory; Dopamine binds to D1 receptors, stimulating excitatory pathway. The net effect is to increase the activity of the thalamus and consequent excitation of the cerebral cortex.
Indirect = inhibitory; Dopamine binds to D2 receptors in the inhibitory pathway. The net effect is to decrease activity of the thalamus and consequently decrease activity of the cerebral cortex. |
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What is the difference between chorea and hemiballismus?
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Chorea is sudden, jerky, purposeless movements characteristic of basal ganglia lesion (eg Huntington's disease).
Hemiballismus is a sudden, wild flailing of one or both extremities; symptoms appear on contralateral side and are usually the result of a lesion of the subthalamic nucleus. |
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What type of tremor would you see in Parkinson's? What type would you see in a cerebellar dysfunction?
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Parkinson's = resting tremor (pill-rolling)
Cerebellar dysfunction = intention tremor |
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Name the brain lesion: Disinhibition and deficits in concentration, orientation and judgement.
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Frontal lobe
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Name the brain lesion: Kluver-Bucy syndrome (hyperorality - examines objects by mouth, hypersexuality, hyperphagia, disinhibited behavior)
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Bilateral temporal lobe lesions that include amygdaloid complex
Kluver-Bucy = Kleaver to Both temporal lobes |
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Name the brain lesion: spatial neglect syndrome (agnosia of the contralateral side of the world)
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Right parietal lobe
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Name the brain lesion: intention tremor or falling toward one side
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Ipsilateral cerebellar hemisphere (patient falls toward side of lesion)
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Name the brain lesion: Anterograde amnesia - inability to make new memories
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Hippocampus
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Name the brain lesion: ability to comprehend with nonfluent aphasia
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Broca's (Broca's Broken Boca)
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Name the brain lesion: Fluent aphasia with impaired comprehension
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Wernicke's (Wernicke's is Wordy; Wernicke's = "What?")
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Name the artery: Supplies the trunk, arm and face areas of the motor and sensory cortices as well as Broca and Wernicke areas
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Middle cerebral artery
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Name the artery: Formed by the two vertebral arteries and provides blood to cerebellum
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Basilar artery
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Name the artery: Supplies medial surface of brain, leg-foot area of motor and sensory cortices
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Anterior cerebral artery
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Name the artery: Supplies the occipital lobe, visual cortex and inferior surface of the temporal lobe (including hippocampal formation). What else does it supply?
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Posterior cerebral artery
It also provides the major blood supply to the midbrain, posterior half of the thalamus and the medial and lateral geniculate bodies. |
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What arteries make up the Circle of Willis?
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Think "Cerebral, Communicating, Carotid"
Anterior, middle and posterior cerebral Anterior and posterior communicating Internal carotid |
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The laceration of this artery results in an epidural hematoma.
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Middle meningeal artery
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What artery gives rise to the PICA?
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Vertebral artery. PICA comes off before these 2 join to form the basilar artery.
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What artery gives rise to the AICA?
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Basilar.
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What is the most common site in the brain for a Berry aneurysm?
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At the bifurcation of the anterior communicating artery
It's also common at the posterior communicating artery. |
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On imaging, what is the main differences between an epidural hematoma and a subdural hematoma?
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Epidural is a biconvex disk and doesn't cross suture lines. However, it can cross the falx and tentorium.
Subdural is a crescent-shaped hemorrhage that crosses suture lines. It can't cross falx or tentorium. |
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What venus sinuses connect at the Confluence of the Sinuses?
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Superior sagittal sinus (superior)
Occipital sinus (inferior) Transverse sinuses (lateral) Straight sinus (anterior) |
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Which sinus is a continuation of the transverse sinus and passes inferiorly and medially into the jugular foramen?
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Sigmoid sinus
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Where does all of the blood of the brain eventually drain?
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Internal jugular vein
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What connects the lateral ventricles to the 3rd ventricle?
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Interventricular Foramina of Monro
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What connects the 3rd ventricle to the 4th ventricle? Where in the brain is it located?
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Cerebral aqueduct - midbrain
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Where in the brain are the lateral, 3rd and 4th ventricles located, respectively?
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Lateral - within the cerebral hemispheres
3rd Ventricle - diencephalon 4th Ventricle - between the cerebellum and the brainstem |
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What connects the 4th ventricle to the subarachnoid space?
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Foramina of Luschka = Lateral
Foramen of Magendie = Medial |
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What makes the CSF? What reabsorbs it?
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CSF is made by the choroid plexus; it is reabsorbed by venous sinus arachnoid villi.
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What 3 structures form the blood-brain barrier?
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1) Tight junctions between nonfenestrated capillary endothelial cells
2) Basement membrane 3) Astrocyte processes |
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In the hypothalamus, the lateral area and ventromedial area are related to hunger and satiety. Which one is which?
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The lateral area --> hunger. It's inhibited by leptin.
The ventromedial area --> satiety. Stimulated by leptin. The lateral area is responsible for you growing laterally if leptin doesn't kick in. |
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Which area of the hypothalamus is responsible for circadian rhythms and receives direct input from the retina?
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Suprachiasmatic nucleus
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What does the anterior hypothalamus do?
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It plays a role in temperature regulation (cooling); it stimulates the parasympathetic system.
Think A/C - Anterior/Cooling |
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How many spinal nerves are there?
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31
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal |
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If it's necessary to do a lumbar puncture, where is it done and what structures are pierced from most superficial to deepest?
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Between L3 and L4 or L4 and L5.
1) Skin/fascia 2) Ligaments (supraspinous, interspinous, ligamentum flavum) 3) Epidural space 4) Dura mater 5) Arachnoid 6) Subarachnoid space - CSF PIA is not PIERCED |
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What is the difference between the spinal epidural space and the cranial epidural space?
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The spinal one is an actual space, the cranial one is a potential space.
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Describe the spinal cord from L1 and below.
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The spinal cord ends in the conus medullaris between L1 and L2. The filum terminale is a continuation of the pia mater that extends to the coccyx. The nerves below L2 flow loosely and are called the cauda equina.
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What are the falx cerebri and falx cerebelli?
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They are formed by the dura mater.
The falx cerebri separates the two hemispheres and contains the superior and inferior sagittal sinuses between its two layers. The falx cerebelli is located below the tentorium cerebelli on the midline of the occipital bone. It extends into the space found between the cerebellar hemispheres and contains the occipital sinus. |
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What is the tentorium cerebelli?
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It is a dural infolding that is over the cerebellum.
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What forms the straight sinus?
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The great cerebral vein and the inferior sagittal sinus
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What are the lobes of the brain?
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Frontal lobe
Parietal lobe Temporal lobe Insular lobe Limbic lobe Occipital lobe |
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What does the lateral sulcus separate? What is the other name for it?
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The temporal lobe from the parietal and frontal.
AKA Sylvian Fissure |
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The thalamus and hypothalamus are in which part of the brain? What was the precursor to this during development?
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The diencephalon, which came from the prosencephalon
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What is located in the precentral gyrus? The postcentral gyrus?
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Precentral gyrus is motor
Postcentral gyrus is sensory |
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Fully describe the spinothalamic tract.
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Lateral - transmits pain and temperature
Ventral - transmits crude touch 1st order neuron - dorsal root ganglia 2nd order neuron - dorsal horn Axons decussate in the ventral white commissure and ascend in the ventral half of the lateral funiculus 3rd order neuron - VPL of thalamus which then project to the somatosensory cortex (areas 3, 1, 2) in the postcentral gyrus. |
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What is the pathway the brain uses to modulate or control pain?
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Periaqueductal gray --> Raphe nucleus --> dorsal horn (Raphespinal fibers)
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What are the two tracts of the dorsal column - medial lemniscal pathway? Where are they located and what are their functions?
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Fasciculus gracilis is more medial and transmits signals from lower body and extremities.
Fasciculus cuneatus is more lateral and transmits signals from the upper body and extremities. They both are involved with pressure, vibration, touch and proprioception. Remember: The dorsal column is organized as we are with arms outside, legs inside. Gracilis = Graceful --> think of long, Graceful legs of a Giraffe |
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Fully describe the dorsal column - medial lemniscal pathway.
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Transmits pressure, vibration, touch and proprioceptive sensation.
1st order neuron - dorsal root ganglion Axon ascend ipsilaterally in dorsal column 2nd order neuron - gracile and cuneate nuclei of the caudal medulla The internal arcuate fibers decussate and form the medial lemniscus 3rd order neuron - VPL nucleu of thalamus which then projects to the somatosensory cortex (areas 3, 1, 2) in the postcentral gyrus |
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Fully describe the spinocerebellar pathway.
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Ventral and Dorsal tracts
Ventral is a crossed tract, Dorsal is uncrossed (remember that if someone crosses your path, it's in front of you, or ventral to you) 1st order neuron in dorsal root ganglion. Ventral 2nd order neuron is in the ventral horn which give rise to axons that decussate in the ventral white commissure and ascend in the lateral funiculus to enter the cerebellum via the SUPERIOR cerebellar peduncle. Dorsal 2nd order neuron is in the nucleus dorsalis of Clarke that give rise to axons that ascend in the lateral funiculus and reach the cerebellum via the INFERIOR cerebellar peduncle. Being in front (ventral) is SUPERIOR to being in back (dorsal). |
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What are the Broadmann areas for the 1) primary motor cortex, 2) premotor cortex, 3) primary somatosensory cortex, 4) primary visual cortex
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1) Primary motor is 4
2) Premotor is 6 3) Primary somatosensory is 3, 1, 2 4) Primary visual cortex is 17 |
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Fully describe the corticospinal path.
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Originates in the cerebral cortex, makes up part of the corona radiata, passes down through the anterior part of POSTERIOR limb of the internal capsule, through the cerebral peduncle to the medullary pyramids
30% from primary motor cortex (MI), 30% from premotor and supplementary motor areas, 40% from primary sensory cortex Lateral corticospinal tract: 1) Decussates in the medulla 2) Travels in the lateral funiculus of spinal cord 3) Terminates in laminae VII and VIII 4) Control of DISTAL musculature Ventral corticospinal tract 1) Travels in the ventral funiculus of spinal cord 2) These fibers decussate in the spinal cord near the target exit 3) Control of AXIAL musculature Remember: Legs are Lateral in the corticospinal and spinothalamic tracts |
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Fully describe the vestibulospinal path.
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Lateral vestibulospinal tract:
1) Originates in the lateral vestibular nucleus in the rostral medulla 2) Uncrossed pathway descends through the ventral funiculus in spinal cord 3) Innervates paravertebral and proximal limb muscles (antigravity extensors) on ipsilateral side 4) Mostly excites extensors Medial vestibulospinal tract: 1) Originates from the medial and inferior vestibular nucleus in the rostral medulla 2) Descends bilaterally (although ipsilateral pathway is more dense) through the MLF as far as the upper thoracic region and influences (mostly inhibits) the motor neurons for neck 3) Run with tectospinal fibers from the superior colliculus of the midbrain |
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Compare the signs of an upper motor neuron lesion to that of a lower motor neuron lesion.
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UMN Lesion:
1) Hyper-reflexia 2) Hyper-tonicity 3) Positive Babinski 4) Spastic paralysis 5) Clasp knife spasticity LMN Lesion: 1) Atrophy 2) Fasciculation (muscle twitching) 3) Hypo-reflexia 4) Hypo-tonicity Remember Upper = everything UP (tone, reflex, toes) Lower = everything LOWERED (tone, reflex, muscle mass, toes) |
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What is the main purpose of the basal ganglia (nuclei)? What makes up the basal ganglia?
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It plays a role in the initiation and execution of somatic motor activity.
The basal ganglia is made up of: 1) Caudate 2) Putamen 3) Globus palidus (externus and internus) 4) Subthalamic nucleus 5) Substantia nigra pars compacta and pars reticulata |
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How does Huntington's and Parkinson's affect the pathway through the basal ganglia?
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Parkinson's:
Reduced dopamine from the substantia nigra pars compacta (SNc) affects both the direct and indirect pathway, since the caudate and putamen receive input from the SNc. Huntington's: The GABA-containing neurons in the caudate, putamen, globus pallidus and substantia nigra pars reticularis (SNr) degenerate, affecting both the direct and indirect pathways and causes atrophy of the caudate and putamen. |
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What makes up the striatum in the basal ganglia?
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Caudate nucleus and Putamen
These 2 are larger nuclei and located lateral to the globus pallidus externus. |
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What are the 4 deep nuclei of the cerebellum and which zones are they located? Which ones are more involved with voluntary movement of extremities and which are involved more with balance, truncal coordination, ataxia and the propensity to fall toward injured side?
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Dentate - Lateral
Emboliform and Globose - Intermediate Fastigial - Medial "Don't Eat Greasy Food" Lateral - voluntary movement of extremities Medial - balance, truncal coordination, ataxia, propensity to fall toward injured side |
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What are the only cells to provide output from the cerebellar cortex? Are they inhibitory or excitatory?
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Purkinje cells - they project mostly to the deep nuclei and are INHIBITORY
PurkINje = INhibitory |
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What cells provide most of the output from the cerebellum?
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The deep nuclei cells from the Dentate, Emboliform, Globose and Fastigial
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What pathway into the cerebellum plays a major role in the maintenance of posture, balance, and the coordination of eye movements?
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Vestibulocerebellar pathway
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Where and at what levels are the sympathetic cell bodies found in the spinal cord?
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Cell bodies located in lamina VII (intermediolateral nucleus) in levels T1 to L2
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What's myelinated, preganglionic axons, postganglionic axons or both?
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Preganglionic are myelinated; therefore to get on the chain ganglia, it must travel through the white ramus.
Remember: Before joining a gang, one is pure (white). |
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When sympathetic input is interrupted through the superior cervical gangion, a condition called Horner's syndrome results. What are the symptoms?
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Horner syndrome: constriction of pupil (miosis), ptosis, flushing and diminished sweating (anhidrosis) of the face.
PAM is Horney P = Ptosis A = Anhidrosis M = Miosis |
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Which lobe is Broca's area located? Which lobe is Wernicke's area located?
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Broca's is in the frontal lobe on the dominant hemisphere.
Wernicke's spans the area between the temporal and parietal lobes on the dominant hemisphere. |
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Are sympathetic preganglionic axons generally short or long compared with parasympathetic preganglionic axons? What are the exceptions?
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Generally short.
The exceptions are when the preganglionic fiber travels to one of the following: Celiac ganglion Aorticorenal ganglion Superior mesenteric ganglion Inferior mesenteric ganglion |
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What organ accepts sympathetic preganglionic fibers directly and why?
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The adrenal glands.
Chromaffin cells of the adrenal medulla are derived from neural crest cells and secrete catecholamines (mostly epinephrine) into the bloodstream. |
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What are the clinical reflexes and their associated spinal nerves that they are testing?
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Biceps - C5
Triceps - C7 Patellar - L4 Achilles - S1 Babinski - positive sign is dorsiflexion of the big toe and fanning of other toes which is a sign of upper motor neuron lesion (except in the 1st year of life) |
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What are the cranial nerves and which are sensory, which are motor, which are both and which are parasympathetic?
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CN I - Olfactory - Sensory
CN II - Optic - Sensory CN III - Oculomotor - Motor, PS CN IV - Trochlear - Motor CN V - Trigeminal - Both CN VI - Abducens - Motor CN VII - Facial - Both, PS CN VIII - Vestibulocochlear - Sensory CN IX - Glossopharyngeal - Both, PS CN X - Vagus - Both, PS CN XI - Accessory - Motor CN XII - Hypoglossal - Motor "Some Say Marry Money But My Brother Says Big Brains Matter Most" |
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Where are the different cranial nerves' nuclei located in the brain? Where are the sensory cranial nerves located and where are the motor nerves located?
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Located in tegmentum portion of brain stem between dorsal and ventral portions.
Midbrain: nuclei of CN III, IV Pons: nuclei of CN V, VI, VII, VIII Medulla: nuclei of CN IX, X, XI, XII Lateral nuclei = sensory (alar plate) Medial nuclei = Motor (basal plate) Remember: M for Medial and Motor |
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What does CN IX do? Which pharyngeal arch is it associated with during development? Which ganglion (or ganglia) is it associated with?
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Glossopharyngeal nerve
Taste from posterior 1/3 of tongue, swallowing, salivation (parotid gland), monitoring carotid body and sinus chemo and baroreceptors and stylopharyngeus (elevates pharynx, larynx) Associated with the 3rd pharyngeal arch. Synapses in the otic ganglion and sends a postganglionic fiber to the parotid gland that increases salivation. |
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What does CN V do? Which pharyngeal arch is it associated with during development?
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Trigeminal nerve
Muscles of mastication, anterior belly of the digastric, mylohyoid, tensor tympani, tensor veli palatini, facial sensation Associated with the 1st pharyngeal arch Remember F = Five (CN V) = First pharyngeal arch |
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What does CN III do? Which ganglion (or ganglia) is it associated with?
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Oculomotor nerve
Eye movement (except SO and LR), pupillary constriction and accommodation (parasympathetic), eyelid opening (levator palpebrae). Associated with the ciliary ganglion Remember: Tea at 3 will keep your eyes open wide! |
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What does CN VII do? Which pharyngeal arch is it associated with during development? Which ganglion (or ganglia) is it associated with?
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Facial nerve
Facial movement, taste from anterior 2/3 of tongue, lacrimation, salivation, eyelid closing (orbicularis oculi - remember: Sunset at 7, time to close your eyes and dream of heaven), stylohyoid, posterior belly of the digastric, stapedius muscle in ear Associated with 2nd pharyngeal arch (Remember: S = Seven (CN VII) = Second pharyngeal arch Associated with both the pterygopalatine ganglion (lacrimal glands and nasal glands) and submandibular ganglion (submandibular and sublingual glands) |
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What does CN X do? Which pharyngeal arch is it associated with during development? Which ganglion (or ganglia) is it associated with?
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Vagus nerve
Cricothyroid muscle (superior laryngeal nerve), all intrinsic muscles of soft palate including levator veli palatini, intrinsic muscles of the larynx, visceral efferent and afferent components distributed to the heart, foregut and a large portion of midgut. Associated with the 4th and 6th pharyngeal arches (Remember: 10 or CN X = 4 + 6) Associated with terminal ganglia on the wall of the target organ |
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What are the pathways for each of the cranial nerves to exit the cranium?
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CN I - Cribiform plate
Middle cranial fossa: CN II - Optic canal (along with ophthalmic artery, central retinal vein) CN III, IV, V1, VI - Superior orbital fissure CN V2 - Foramen Rotundum CN V3 - Foramen Ovale Also, the middle meningeal artery goes through Foramen Spinosum Posterior cranial fossa: CN VII, VIII - Internal auditory meatus CN IX, X, XI - Jugular foramen (along with jugular vein) CN XII - Hypoglossal canal Also, the spinal roots of CN XI, the brain stem and vertebral arteries go through the Foramen Magnum. Tip for remembering CN V: Divisions of CN V exit owing to Standing Room Only S: Superior orbital fissure (V1) R: Foramen rotundum (V2) O: Foramen ovale (V3) |
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What is the location in the cavernous sinus where the pituitary gland sits?
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Sella turcica
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In a lesion of CN XII, which side does the tongue deviate?
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The tongue deviates TOWARD the side of the lesion.
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All muscles with the root "glossus" in their names (except for one) are innervated by the hypoGLOSSAL nerve. What's the exception?
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The palatoglossus nerve that's innervated by the vagus nerve.
Remember: all muscles with the root "palat" in their names are innervated by the vagus nerve (except for tensor veli palatini - CN V). "We go to Vegas to please our Palate, except for Tensor veli palatini who was too TENSE to go." |
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All muscles with the root "palat" in their names (except for one) are innervated by the vagus nerve. What's the exception?
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Tensor veli palatini - innervated by mandibular branch of CN V
"We go to Vegas to please our Palate, except for Tensor veli palatini who was too TENSE to go." |
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What are the 4 muscles of mastication? Which ones open the jaw and which ones close it?
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M's Munch (close the jaw):
Masseter teMporails Medial pterygoid Lateral Lowers the jaw (or lets you go "La-La-La": Lateral pterygoid |
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In the inner ear: what detects horizontal acceleration, vertical acceleration, and angular acceleration?
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2 otolith organs:
Utricle - horizontal Saccule - vertical 3 Semicircular canals - angular Picture a Unicycle going fast horizontally and a person going up in an elevator carrying SACs |
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Describe endolymph and perilymph in the bony labyrinth in terms of Na+ and K+
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Perilymph is high in Na+ like extracellular fluid
Endolymph is high in K+ like intracellular fluid |
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What is the Rinne test? What is a normal finding?
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Tuning fork placed on mastoid until person can't hear it, then put close to ear until person can't hear it.
Normal: air conduction > bone conduction |
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What is the Weber test? What is an abnormal finding?
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Tuning fork on top of head.
Conduction deafness: sound lateralizes to that ear Sensorineural loss: sound lateralizes to opposite ear |
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What area of the macula has the sharpest vision? Why?
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The fovea. It has all cones and no rods.
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Which are more light sensitive, rods or cones?
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Rods. They are what allow us to see in the dark.
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This part of the eye is contiguous with the sclera but has no vascular supply.
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Cornea
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What happens to the lens and ciliary muscle in near-sightedness?
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Zonular fibers relax --> ciliary muscle contracts and lens relaxes --> becomes more convex
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What is the sclera?
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Tough, connective tissue covered by the conjunctiva
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What happens in glaucoma? What are the 2 types and how do they differ?
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Impaired flow of aqueous humor --> increased intraocular pressure --> optic disk atrophy with cupping
Open/wide angle - obstructed outflow (eg canal of Schlemm); associated with myopia, increased age, African-American race; this is more common and is "silent", painless. Closed/narrow angle - obstruction of flow between iris and cornea --> pressure buildup behind iris. Very painful. Decreased vision, rock-hard eye, frontal headache, ophthalmologic emergency. Remember: O = Open = Obstructed Outflow = Old age = Often Occurs (more than closed angle) |
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If there were damage CN IV on one side, what would the eye do?
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CN IV innervates the superior oblique which depresses the eye while it's adducted. Therefore, one eye would be unable to look downward when adducted.
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What does the inferior oblique muscle do?
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Causes the eye to look up.
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What is the path for parasympathetic innervation of the pupil? What does it do to the pupil?
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CN III from Edinger-Westphal nucleus --> ciliary ganglion --> pupillary sphincter muscle --> constricts the pupil (miosis)
"This is the THIRD time I'm telling you: 'hEaD WEST you CILI, AiRY thing, where people are more laid back' (parasympathetic)" |
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What is the path for sympathetic innervation of the pupil? What does it do to the pupil?
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T1 preganglionic sympathetic -> superior cervical ganglion --> postganglionic sympathetic --> long ciliary nerve
Causes myDriasis (Dilation) |
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If the right optic nerve were severed, what would be the defect in the visual field?
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Right anopia (blind in right eye)
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If the right optic tract were severed, what would be the defect in the visual field?
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Left homonymous hemianopsia (failure to see the left visual field in both eyes).
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If the decussating fibers in the optic chiasm were severed, what would be the defect in the visual field?
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Bitemporal hemianopsia (failure to see the right visual field in the right eye, and the left visual field in the left eye).
Remember that the nasal fibers are the ones that decussate, and those have the temporal visual field. |
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Where does Meyer's loop run and what would be the defect in the visual field if it were severed on the right side?
Where does the dorsal optic radiation pass and if it were severed on the right side, what would be the defect in the visual field? |
From the LGN (lateral geniculate nucleus), two bundles are radiated to the primary visual cortex. One of these is the Meyer's loop and it passes through the white matter of the temporal lobe. These fibers carry information from the inferior retina (upper visual field).
A lesion on the right Meyer's loop would result in left upper quadrantic anopia (failure to see the left upper quadrant in both eyes). The other bundle runs through the internal capsule and it contains information from the superior retina (lower visual field). If it were severed, one would have left lower quadrantic anopia. |
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Describe the difference between cerebral edema and hydrocephalus.
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Cerebral edema: due to increased vascular permeability, altered regulation of fluid or transudation
Common after injury, radiation, long term HTN Hydrocephalus: due to increased CSF causing 3rd and 4th ventricles to swell |
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What kind of necrosis occurs in the brain after an infarction due to an embolus or thrombus?
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Liquifactive necrosis
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Which layer of the retina breaks down in macular degeneration? What defect occurs in the field of vision?
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The pigment layer breaks down. These cell line the back of the retina.
The center visual field is lost. |
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Who is affected by ALS/Lou Gerhig's?
What are the symptoms/signs? How does death usually occur? |
Men 50-60
Loss of both lower & upper motor neurons Mixed symptom presentation: Muscular atrophy Weakness Hyper-reflexia Death following respiratory complication (10% due to autosomal dominance) |
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What is the name of the cells lining the pia mater in the ventricles? Histologically, what type of cells are they? What do they form?
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Ependymal cells
Simple cuboidal They form the choroid plexus that produces CSF |
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What reabsorbs the CSF and returns it to the bloodstream?
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Arachnoid villi in the superior sagittal venous sinus
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What is Guillain-Barre syndrome?
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It's an immune disorder that produces inflammation and rapid demyelination within the peripheral nerves and the motor nerves arising from the ventral roots. It's associated with infections and is due to molecular mimicry (e.g. Campylobacter jejuni or herpesvirus infection). Symptoms include muscle weakness in the extremities and ASCENDING paralysis (GB = Ground to Brain)
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What do these have in common?
1) Guillain-Barre 2) Multiple Sclerosis 3) Perivenous (postinfectious) Encephalomyelitis |
They are all demyelinating diseases.
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What are the symptoms of Wernicke-Korsakoff and what causes it? What group of people does it most often affect?
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Confusion, ataxia, memory loss, confabulation, personality change.
Caused by B1 (thiamine) deficiency. Often seen in alcoholics. |
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Prolonged deficiency of this vitamin leads to irreversible nervous system damage. It is a cofactor for homocysteine methyltransferase.
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B12
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What are the histological findings of Alzheimer's? What lipoprotein can be indicative of late onset Alzheimer's? Which lipoprotein is protective?
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Beta-amyloid plaques
Neurofibrillary tangles (intracellular, abnormally phosphorylated tau protein) ApoE4 = late onset ApoE2 is protective |
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Name the disease:
- Usually occurs in persons 50 to 70 years old - Affects 2x as many men as women - Involves both LMN's and UMN's - Can be caused by defect in superoxide dismutase 1 (SOD1) - Commonly presents as fasciculations |
Amyotrophic Lateral Sclerosis
(Lou Gehrig's Disease) |
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This viral encephalitis of the CNS is associated with rubeola (measles) virus. It has intranuclear inclusions in neurons and oligodendrocytes and death usually occurs within 1-2 years.
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Subacute sclerosing panencephalitis
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This viral encephalitis is due to a papovavirus (Polyomavirus) called JC virus. It presents with intranuclear inclusion in oligodendrocytes, demyelination of CNS and occurs in AIDS patients.
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Progressive multifocal leukoencephalopathy (PML)
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What is the most common location for primary brain tumors in adults? In children? (Hint: Are they above the tentorium cerebelli or below it?)
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Adults: 70% above tentorium cerebelli
Children: 70% below tentorium cerebelli |
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What is the most common primary brain tumor in adults? Where is it commonly found? What is the histological finding? What is the prognosis?
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Gliobastoma (Grade IV Astrocytoma)
Found in cerebral hemispheres Multifocal areas of necrosis and cystic degeneration Poor prognosis |
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What type of tumor is a malignant small cell tumor primarily occurring in children that arises from the external granular cell layer of the cerebellum? What complication can it cause?
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Medulloblastoma
It can invade the 4th ventricle, causing hydrocephalus |
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A patient fractured their medial epicondyle of the humerus and now has a "claw hand". What nerve was injured?
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Ulnar nerve - loss of interosseous muscles
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A patient fractured the midshaft of their humerus and the injury produced a wrist drop. Which nerve was injured?
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Radial nerve
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Patient fractured the surgical neck of the humerus and now cannot abduct the arm to a horizontal position. Which nerve was injured?
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Axillary nerve
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What nerve is affected in carpal tunnel syndrome? What are the symptoms and what tests are positive?
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Median nerve
Pain or numbness in the thumb, 2nd, 3rd fingers and radial side of 4th finger Tinel's and Phalen's sign will be positive |
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What does Erb-Duchenne palsy cause?
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Waiter's tip deformity from a brachial plexus lesion involving C5 and C6
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What bone of the skull contains the sella tursica?
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Sphenoid
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Which muscle opens the eye? Which one closes it? What is the innervation for each?
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Opens: Levator Palpebrae Superioris innervated by CN III (picture the III propping it open)
Closes: Orbicularis Occuli innervated by CN XII (picture a "7" hooking the lid and closing the eye) |
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There are 3 peduncles connecting the cerebellum. What are they and what is the primary purpose of each?
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Inferior cerebellar peduncle: Input from Ipsilateral side of body via the dorsal spinocerebellar tract
Middle cerebellar peduncle: Input from contralateral side of cortex via pontocerebellar fibers Superior cerebellar peduncle: Output to contralateral cortex via fibers from the deep nuclei to the thalamus |
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Do the eyes look toward or away from the side of the lesion when there is damage to the frontal eye fields?
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Toward the lesion
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What laryngeal muscle would be spared if there was an injury to the recurrent laryngeal nerve?
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The cricothyroid (innervated by external branch of SUPERIOR laryngeal nerve)
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What is the name of the conduction path that connects Broca's and Wernicke's areas?
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Arcuate fasciculus
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Describe the locations of the anterior spinal and posterior spinal arteries. What do they supply? What are they branches of?
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Anterior spinal artery lies along the anterior surface of the spinal cord and supplies the anterior 2/3 of the spinal cord.
The posterior spinal arteries (2) run along the posterior side of spinal cord and supply the posterior 1/3 including posterior horns and dorsal columns. They both are branches off of the vertebral arteries. |
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What part of the nervous system does poliomyelitis affect?
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Poliovirus replicates in the oropharynx and small intestine before spreading through the blood stream to the CNS, where it leads to the destruction of cells in the anterior horn of the spinal cord, leading to LMN destruction.
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In ALS, what is spared?
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While there are both UMN and LMN signs, there are no sensory, cognitive or oculomotor deficits.
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What does neurosyphilis cause?
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Tabes dorsalis - degeneration of dorsal columns and dorsal roots leading to impaired proprioception and locomotor ataxia.
Associated with Charcot's joints, Argyll Robertson pupils (reactive to accommodatin but not to light), absence of deep tendon reflexes, positive Romberg (patient is asked to stand up and close his eyes) |
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What's the difference between muscle spindle fibers and Golgi tendons?
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Muscle spindle: in parallel with extrafusal muscles; monitor muscle length
Golgi tendons: in series with intrafusal muscles, monitor tension |
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Which cranial nerve is the only one that arises dorsally and immediately decussates?
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CN IV
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Where are the superior colliculi and inferior colliculi located and what do they do?
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Midbrain.
Superior - conjugate vertical gaze center Inferior - auditory |
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What do the procencephalon, mesencephalon and rhombencephalon become?
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Procencephalon --> telencephalon (which becomes cerebral hemisphere and lateral ventricles) and diencephalon (which becomes the thalamus and 3rd ventricles)
Mesenchephalon --> midbrain and aqueduct Rhombencephalon --> metencephalon (pons and cerebellum) and the upper part of 4th ventricle) and myelencephalon (medula and lower part of 4th ventricle) |
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Give the afferent and efferent cranial nerves for the following reflexes:
Corneal Lacrimation Pupillary Gag |
Corneal: Afferent is V1, Efferent is VII
Lacrimation: Afferent is V1, Efferent is VII Pupillary: Afferent is II, Efferent is III Gag: Afferent is X, Efferent is IX, X |
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What type of collagen makes up the sclera?
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Type I collagen fibers interlaced with elastic fibers
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What is the space anterior to the iris?
a. Anterior chamber b. Posterior chamber c. Vitreal cavity d. Both a and b e. All of a, b, and c |
Answer: a
The region behind the lens is the vitreal cavity. The chambers anterior to the lens are the anterior chamber and posterior chamber. The iris separates the anterior chamber from the posterior chamber. |
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Which contains perilymph?
a. Scala vestibuli b. Scala tympani c. Cochlear duct d. Both a and b e. All a, b, and c |
Answer: d
The scala vestibuli and scala tympani contain perilymph. The cochlear duct contains endolymph. |
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What is the only muscle that CN IX provides motor innervation to?
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Stylopharyngeal muscle
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T/F: the internal carotid has no branches until it gets inside the skull
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True. The first branch is opthalmic artery
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