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85 Cards in this Set
- Front
- Back
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What is the sequence of formation of the CNS?
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Embryonic ectoderm
Neural Plate Neural Groove Neural Tube Basal Lamina (Basement Membrane, glia limitans) Glia Limitans is boundary between CNS and PNS Neural Tube becomes the brain and spinal cord, hollow part becomes the ventricles and central canal of spinal cord Surrounded by meninges, composed of dura, arachnoid and pia |
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List the 5 components of nervous tissue
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CNS
PNS Parasympathetic Sympathetic Enteric |
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Indicate 8 classes neurons
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Motor
Sensory Preganglionic Parasympathetic Postganglionic Parasympathetic Preganglionic Sympathetic Postganglionic Sympathetic Enteric Interneurons |
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Cite the three types of neuroglia
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Oligodendrocytes
Astrocytes Ependymal |
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Compare and contrast cilia with microvilli
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Cilia are complex motile structures extending from the apical surface of cells. Internal contraction method is called an axenome. Power bend in one direction, weak recovery bend in the opposite direction. Important in moving CSF.
Microvilli extend from other cell apical surfaces. Microvilli increase surface area to maxiize secretion and adsorption and transport channels. |
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What is the role(s) of myelination?
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Insulation of axon to promote rapid transmission of action potential. In the CNS, this is accomplished by oligodendrocytes, in the PNS, this is done by Schwan cells
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What are the 3 invaders of the CNS?
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Microglia (throughout the neuropil)
Endothelium (vascular invaders) Perivascular macrophages |
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Draw and label a spinal cord cross-section
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Thin dorsal horn - Sensory inputs from sensory neurons whose nucleus is located in the dorsal ganglion
Ventral horn (bulbous) contains motor neurons Gray commisure Central canal (lined by ependymal cells) |
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List functions of the blood brain barrier (BBB)
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- Keep plasma toxins out of the neuropil
- Prevent tiny plasma vascillations of ions from impacting the neuropil - Exclude all circulating neurotransmitters, plasma growth factors and plasma proteins from the neuropil - Keep neuropil transmitters within the neuropil |
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Restate the structural components and channels of the BBB
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- 5x tight junctions (not in 1st year of life)
- Unique transport channels (carrier mediated for L-amino acids, D-glucose & essential amino acids the neuropil cannot synthesize - Active purge transport from neuropil into capillary lumen (purge mechanism) - Induced by astrocytes whose foot processes totally surround each capillary but are not the barrier proper - Astrocytes have a funnel function to dump waste products around the basal surface of the endothelial cells (purge mechanism) |
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Interpret the Oldendorf plot
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-Substances enter the neuropil from the capillary by their lipid solubility (nonpolar, hydrophobic)
-Greater rate that hydrophobicity means that transport is carrier mediated (D-glucose) -Lesser rate than hydrophobicity means that substance is bound to albumin -Example - morphine is very polar, so it doesn't get through. Heroin (more non-polar) does get through faster - |
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Explain the functions of the CSF
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- Purge the neuropil via equilibrium between ECF and CSF across the pia meningiothelial in subarachnoid space and ependymal cells in the 4 ventricles of the brain
-Brain buoyance (1400 gram brain weighs 60 grams due to bouyance) -Protects the brain from hitting the bones of the calvarium (brain in box or Monro-Kellie doctrine) -Provides micronutrients of the brain |
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5 Critical facts about CSF
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- 150 ml of CSF in the CNS
- Synthesized by choroid plexus - 0.4ml/minute, 24ml/hour - turnover 4x/day - colorless - sampled by lumbar puncture at L4-L5 |
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Draw and label a choroid plexus
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-Fronds hang down into the 4 ventricles
-Total weight of 3 grams -Dense capillary network, very leaky -Covered by unique epithelial cells with apical microvilli -Bidirectional active transport to secrete micronutrients and purge impurities -Huge in fetal lateral ventricles -smaller with normal aging |
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Compare and contrast the functions of the BBB with those of the choroid plexus
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BBB - 5x tight junctions, uses Oldendorf mechanism and active transport
Choroid plexus - leaky junctions (fenestrae, etc), produces CSF |
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Diagram the flow of the CSF
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-Lateral ventricles
-2 interventricular foramen of Monro -3rd ventricle -aqueduct of Sylvius -4th ventricle -lateral foramen of Luschka (2) and one medial foramen of Magendie into cisterna magna -spinal and cerebral subarachnoid spaces -arachnoid granulations dump into venous spaces which drain into jugular vein |
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Describe the 5 molecular purges of the ECF in the neuropil (between the pia and ependymal cells)
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-active transport across blood brain barrier
-funnel function of astrocytes -active transport across epithelium of choroid plexus into loose connective tissue -equilibrium of ECF and CSF across pia -equilibrium of ECF and CSF across ependymal cells |
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What is the effect of increased head diameter of a child and papilledema of the optic nerve head?
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CSM in spinal nerve sleeve of subarachnoid space. Optic nerve bulging in both eyes (papilledema) indicates increased CSF pressure
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List seven characteristics of a neuron
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Post-mitotic
3 structural configurations -Pseudounipolar (sensory) -Multipolar (motor, preganglionic & post ganglionic) -Bipolar(olfaction, vision, vestibular & auditory) -Interneurons Soma (perikaryon) large nucleus with active DNA, prominent nucleolus Multipolar neurons have numerous dendrites Many chemical synapses Extensive axonal transport away from and towards the soma |
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Interpret the significance of tight junctions
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- composed of transmembrane proteins
- cross the lipid bilayer many times - have domains on the extracelluar side of the plasma membrane - have domains onthe protoplasmic side of the plasma membrane - extracellular domains interact forming a barrier - the more proteins involved, the tighter the barrier - some have tight tight tight tight tight junctions and others have tight hunctions |
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Specify the functions of the three components of the cytoskeleton
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1 - Microtubules of tubulin
2 - Microfilaments of actin 3 - Intermediate filaments |
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Organize a list of the intermediate filaments unique to each cell type in the CNS and PNS
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Cytokeratin
Neurofilament GFAP in neuroflia & ependymal cells Vimentin in Schwann, pia, arachnoid, endothelial, microglia, etc. |
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Compare oligodendrocytes to Schwann cells
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Oligodendrocytes
- CNS white matter - Plasma membrane fusions - No basal lamina - channels patched at node of Ranvier Schwann cells - PNS - Lipid proliferation causes rotation around axon - Basement membrane - 20-30 rotations - Not all axons are myelinated |
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Describe the process of myelin formation around axons
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- Lipid proliferation causes rotation around axon
- Basement membrane - 20-30 rotations |
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Draw and label the structure of a cross section and logitudinal section of a peripheral nerve
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Epineurium - surrounds entire nerve proper and partitions the nerve in to fascicles
Perineurium - surrounds each nerve fascicle. 5-7 layers of epithelial-like flat cells with tight junctions Endoneurium - basement membrane of Schwann cells. Also contains capillary bed. |
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State the significance of a synapse
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Not covered in my notes - but from past recollections:
Synapse enables conduction without physical connection |
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Interpret why axonal regeneration within the CNS is so problematic while axonal regeneration within the PNS is a common reality
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Has to do with astrocyte proliferation in CNS. Astrocytes inhibit axonal growth in CNS. Basement membrane in PNS enables nerve regeneration
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Describe the purpose of the neurological exam
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Find the lesion, localize the lesion.
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List the 8 parts of the neurological exam
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Mental status
Speech and language Cranial Nerves Motor Deep Tendon Reflexes Sensory Coordination Gait |
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What part of the brain does the mental status exam involve?
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Cortex and subcortex
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What part of the brain does the speech and language exam involve?
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Cortex (language)
Cortex to lips, tongue and larynx (speech) |
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The brainstem involves which part of the neuro exam?
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Cranial nerves
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The motor exam tests which part of the brain?
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Cortex to muscle
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The sensory exam tests which part of the brain?
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Skin to cortex
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Testing coordination focuses on which brain regions?
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Basal ganglia and cerebellum
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Which part of the neuro exam tests all functions of the brain?
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Gait
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List the three planes of section you might see as you examine the brain or brain images?
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Axial (horizontal through the brain)
Coronal (front to back) Sagittal (side to side - mid sagittal goes right through the middle of the brian) |
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What are parts of the brainstem?
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Midbrain
Pons Medulla oblongota |
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What part of the brain is located on the outside of the cerebrum?
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Cortex
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How many layers exist in the normal cortex microanatomy?
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6 layers
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At which vertebral joint does the spinal cord end?
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L1-L2
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What are the important sub-parts of the cerebrum?
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Cortex
Basal ganglia Thalamus |
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Name the sub parts of the basal ganglia
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Caudate nucleus (head)
Putamen Globus Pallidus Caudate nucleus (tail) |
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What structure connects the cerebellum to the rest of the brain?
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Piduncles
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Name the 4 sections of spinal column
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Cervical
Thoracic Lumbar Sacral |
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Name the structure that connects the 3rd and 4th ventricle
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Aquaduct
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What are the two main tracts of the sensory nervous system?
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Fine touch
Pain & Temperature |
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Where do the sensory systems synapse (which brain structure)
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Thalamus
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Name the two parts of the motor system
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Pyramidal
Extrapyramidal |
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Which parts of the brain structure are most important in the extrapyramidal motor system
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Basal ganglia
Cerebellum |
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Name 5 of the functions of the extrapyramidal motor system
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Preparing to move
Stopping movement Smoothness of movement accuracy of movement rhythm of movement |
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Name 5 "systems" of neural function
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Sensory
Motor - Pyramidal Motor - Extrapyramidal Cranial Higher Cortical Functions (mental status & speech) |
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Dorsal columns carry what type of information?
Motor Sensory Enteric Autonomic |
Sensory
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Anterolateral System is also known as
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Spinothalamic tract
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What are the two principal sensory systems?
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Fine touch
Pinprick (pain) |
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Sensory exam components are?
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Test light touch and pinprick
- Proximal to distal - Side to side - Arms to legs - Face to extremities |
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Autonomic neurons reside in what part of the spinal column?
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Lateral horn of gray matter
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Motor neurons reside in what part of the spinal column
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Ventral (anterior) gray matter
Bulbous horn of the gray matter |
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What is the name of the structures that comprise the white matter of the spinal column
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Funiculus
3 parts Posterior (dorsal) Lateral Anterior (ventral) |
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Name the 3 arteries that supply the spinal cord blood supply
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Anterior spinal artery (2/3) supply
2 Posterior spinal arteries (1/3) supply |
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Dorsal columns in the spinal cord carry what type of signals?
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fine touch
vibration joint position |
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Dorsal column nerve fibers synapse in what structure?
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Medulla (1st order)
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Dorsal column second order nerves synapse in what structure?
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thalamus
Then travel in the posterior limb of the internal capsule |
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Dorsal column nerves travel on what side?
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ipsilateral
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3rd order dorsal column nerves terminate where?
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Primary sensory cortex in the parietal lobe
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The 3 main arteries that supply the sensory cortex are:
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Anterior cerebral artery (superior cortex)
Middle cerebral artery (middle cortex) Posterior cerebral artery (inferior cortex) |
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The spinothalamic tract (anterolateral system) carries what information?
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pain, temperature, crude touch, itch, tickle
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First order spinothalamic fibers synapse in what area?
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substantia gelatinosa on the ipsilateral side of spinal cord
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Second order spinothalamic fibers synapse in what area?
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Synapse in the thalamus.
After the first order synapse, the second order fibers cross via the anterior white commissure and travel in contralateral spinothalamic tract. |
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Second order spinothalamic fibers continue to travel in contralateral ST tract through the brainstem
True False |
True
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Second order spinothalamic tract fibers synapse in the thalamus then travel in posterior limb of internal capsule
True False |
True
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Afferent = incoming signals
Efferent = outgoing signals True False |
True
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Leg tracts are medial through the brainstem
True False |
False
Legs Lateral |
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Where does the corticospinal (pyramidal) tract begin?
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Precentral gyrus
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Which layer of cortex gives rise to the pyramidal tract
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5th layer
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Where do corticospinal fibers travel in the brain?
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Posterior limb of the internal capsule
(Legs are lateral) |
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Where do the corticospinal fibers cross to the other side?
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Junction of medulla and cervical spinal cord
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Where do the corticospinal tract synapse?
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Anterior horn (ventral horn)
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What substance is released at the neuromuscular junction
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Calcium
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at the neuromuscular junction, synaptic vessicles in the axon contain what chemical compound?
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ACh
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Basement membrane of the NM junction contains what chemical compound
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AChE
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Deep tendon reflex is initiated by what structure?
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muscle spindle (contained in plexus)
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Sensory neurons in deep tendon reflexes synapse with what?
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With interneurons
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What are the characteristics of an upper motor neuron lesion?
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Weakness
Increased tone (spasticity) Increased reflexes Babinski with upgoing toes |
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What are the characteristics of a lower (PNS) motor neuron lesion
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Weakness
Decreased tone Fasciculations Decreased reflexes Babinski with downgoing toes |
