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519 Cards in this Set
- Front
- Back
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What is the #1 neurological disease?
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Stroke
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What does the central nervous system consist of?
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Brain stem, spinal cord, cerebellum, and diencephalon
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What is the primary responsibility of the CNS?
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Survival
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Where is visual information processed?
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Occipital lobe
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Where is auditory information processed?
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Temporal lobe
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Where is cognitive or "personality" information processed?
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Frontal lobe
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Where is memory information processed?
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Temporal lobe
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Where is the motor information processed?
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Frontal lobe
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Where is the major relay station for all sensory information?
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Thalamus
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What do neurons consist of?
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Cell bodies, axons, dendrites
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What is the site of action in a neuron?
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The dendritic spines
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What are sensory neuron?
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Afferent
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What are motor neurons?
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Efferent
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What are interneurons?
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95% of neurons; integrate sensory and motor; doing all the work
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Where are the lower motor neurons?
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They leave the brain and spinal cord through peripheal neurons and go to muscles
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Where are the upper motor neurons?
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They go to the spinal cord
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What neurons does Polio virus affect?
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Lower motor neurons
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What neurons does Lou Gerig's disease affect?
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Upper and lower motor neurons
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What are the conduit for the information to enter our CNS?
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Sensory neurons; afferents
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What are the conduit for the output from our CNS?
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Motor neurons; efferents
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What kinds of neurons does the dorsal root ganglia contain?
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Pseudounipolar
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What are the two types of interneurons?
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Projection and local interneurons
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What are glial cells in the CNS?
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Astrocytes, oligodendrites, and microglial cells
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What do astrocytes do?
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Maintain homeostasis; major source of growth factor
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What do oligodendrocites do?
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Myelination in the CNS; inhibit growth
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What do microglial cells do?
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Process is unknown
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What are the glial cells in the PNS?
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Schwann and satellite cells
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Where are Schwann cells?
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myelinating and unmyelinating
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Where are Satellite cells?
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next to cell bodies of peripheral sensory neurons
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What are the three parts of the brainstem?
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Medulla, pons, and midbrain
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Rostral end.....
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The front of the brain
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Caudal end....
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the back of the brain
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Fasiculis Gracilis....
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carrying sensory info from leg; below t6
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Fasiculis cuneatus.....
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above t6
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Gray matter.....
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Cell bodies
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White matter....
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myelinated axons
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What are faniculi?
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Chunks of white matter
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What are roots composed of?
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Rootlets
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Ventral....
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Motor
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Dorsal....
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Sensory
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What does the forebrain consist of?
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Telencephalon and Diencephalon
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What does the diencephalon contain?
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Thalamus and hypothalamus
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Where is the 3rd ventricle located?
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Diencephalon
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Central sulcus also called.....
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Rolando
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Lateral sulcus also called....
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Sylvian fissure
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What does the central sulcus separate?
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Frontal from parietal lobe
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What does the lateral sulcus separate?
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Frontal from temporal lobe and parietal from temporal lobe
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What does the paracentral lobule consist of?
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The precentral and postcentral gyrus
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Where is the motor cortex located?
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The precentral gyrus
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Where is the somatosensory cortex located?
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The postcentral gyrus
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Where is the calcarine sulcus located?
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In the occipital lobe; visual cortex
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What is the gyrus called within the limbic lobe?
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The singulate gyrus
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What does the limbic lobe control?
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Emotions and memory
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What are the 3 gyri located in the temporal lobe?
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Superior, middle and inferior temporal gyrus
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What does the inferior temporal gyrus do?
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Face recognition
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What sits in the superior temporal gyrus?
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Auditory cortex
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What are the 3 gyri located in the frontal lobe?
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Superior, middle, and inferior frontal gyrus
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What are the parts of the inferior frontal gyrus?
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Pars opercularis, pars triangularis, and pars orbitalis
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What special thing is located in the pars opercularis and pars triangularis?
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Brocca's area
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What does Brocca's area control?
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Speech and language
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What does the postcentral gyrus map?
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The face, arm and trunk
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What does the paracentral lobule map?
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The legs and feet
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What kind of information do the caliculi receive?
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Sensory information
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What does the superior caliculi receive?
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Visual info
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What does the inferior caliculi receive?
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Auditory info
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What area of the brain is cranial nerve II located?
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Diencepahlon
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What area of the brain is cranial nerve III located?
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Midbrain
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What is the only cranial nerve that comes off the doral side of the brain?
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Trochlear nerve (IV)
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Where is cranial nerve XII located?
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Between the olive and the pyramid in the medulla
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Where do IX, X, XI, and XII exit?
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The medulla
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Where do V, VI, VII, VIII exit?
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Pons
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Where are the colliculi located?
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Midbrain
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What are the peduncles?
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Major pathways connecting the cortex, cerebellum, and the brain stem
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What is the facial colliculus?
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fiber bundles of cranial nerve VII
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What do the neural crest cells give rise to?
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The majority of the cells in the peripheal nervous system
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What are specific examples of things neural crest cells give rise to?
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Dorsal root ganglia, sympathetic ganglia, parasympathetic ganglia, adrenal medulla, enteric nervous system
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What are the 3 bulges in the neural tube?
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Prosencephalon, mesencephalon, and rhombencephalon
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What does the prosencephalon give rise to?
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Telencephalon and Diencephalon
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What does the telencephalon give rise to?
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Cerebral hemispheres and basal ganglia
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What does the diencephalon give rise to?
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Thalamus, Hypothalamus, and Retina
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What does the mesencephalon contain?
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Midbrain and cerebral aqueduct
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What does the rhombencepahlon give rise to?
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Metencephalon and Myelencephalon
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What does the mesencephalon give rise to?
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Cerebellum and Pons
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What does the myelencephalon give rise to?
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Medulla
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Which ventricle forms a diamond shape?
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4th ventricle
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What happens when the anterior neuropore fails to close?
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Anencephaly
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What happens when the posterior neuropore fails to close?
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Spina bifida
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What is the sulcus limitans?
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Divides the spinal cord into the dorsal/sensory ALAR plate and the ventral/motor BASAL plate
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What does the ALAR plate do?
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Sensory
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What do the neural crest cells give rise to?
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The majority of the cells in the peripheal nervous system
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What are specific examples of things neural crest cells give rise to?
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Dorsal root ganglia, sympathetic ganglia, parasympathetic ganglia, adrenal medulla, enteric nervous system
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What are the 3 bulges in the neural tube?
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Prosencephalon, mesencephalon, and rhombencephalon
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What does the prosencephalon give rise to?
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Telencephalon and Diencephalon
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What does the telencephalon give rise to?
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Cerebral hemispheres and basal ganglia
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What does the diencephalon give rise to?
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Thalamus, Hypothalamus, and Retina
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What does the mesencephalon contain?
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Midbrain and cerebral aqueduct
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What does the rhombencepahlon give rise to?
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Metencephalon and Myelencephalon
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What does the mesencephalon give rise to?
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Cerebellum and Pons
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What does the myelencephalon give rise to?
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Medulla
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Which ventricle forms a diamond shape?
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4th ventricle
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What happens when the anterior neuropore fails to close?
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Anencephaly
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What happens when the posterior neuropore fails to close?
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Spina bifida
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What is the sulcus limitans?
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Divides the spinal cord into the dorsal/sensory ALAR plate and the ventral/motor BASAL plate
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What does the ALAR plate do?
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Sensory
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What do the neural crest cells give rise to?
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The majority of the cells in the peripheal nervous system
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What are specific examples of things neural crest cells give rise to?
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Dorsal root ganglia, sympathetic ganglia, parasympathetic ganglia, adrenal medulla, enteric nervous system
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What are the 3 bulges in the neural tube?
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Prosencephalon, mesencephalon, and rhombencephalon
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What does the prosencephalon give rise to?
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Telencephalon and Diencephalon
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What does the telencephalon give rise to?
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Cerebral hemispheres and basal ganglia
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What does the diencephalon give rise to?
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Thalamus, Hypothalamus, and Retina
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What does the mesencephalon contain?
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Midbrain and cerebral aqueduct
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What does the rhombencepahlon give rise to?
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Metencephalon and Myelencephalon
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What does the mesencephalon give rise to?
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Cerebellum and Pons
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What does the myelencephalon give rise to?
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Medulla
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Which ventricle forms a diamond shape?
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4th ventricle
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What happens when the anterior neuropore fails to close?
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Anencephaly
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What happens when the posterior neuropore fails to close?
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Spina bifida
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What is the sulcus limitans?
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Divides the spinal cord into the dorsal/sensory ALAR plate and the ventral/motor BASAL plate
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What does the ALAR plate do?
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Sensory
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What does the BASAL plate do?
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Motor
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Where do lower motor neurons synapse?
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On muscle
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In the 4th ventricle, what causes the walls to spread apart?
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The pontine flexure
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What is the result of the pontine flexure?
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The dorsal-ventral arrangement of sensory and motor areas become arranged laterally-medially.
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In the medulla, which is most medial (motor or sensory)?
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Motor is the most medial
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In the medulla, which is most lateral (motor or sensory)?
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Sensory is the most lateral
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How do you tell if a cerebral hemisphere is mature?
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If it has gyri it is mature; if it is smooth it is immature
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Where are neurons born?
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Ventricular zone
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How many cell layers extend out from the ventriclar zone?
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6
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The oldest neuron is located in which cell layer?
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6th
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When does migration in the cortex peak?
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Between the 11th and 15th week of gestation
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When do the majority of cells complete migration in the cortex?
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By the 24th week
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What is a disorder of neuronal proliferation and/or survival?
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Microcephaly
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What is microcephaly?
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Small head; brain doesn't achieve normal size
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What is a disorder of neuronal migration?
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Lissencephaly
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What is lissencephaly?
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smooth brain; normal gyrations absent or reduced so brain appears smooth; cortex is thickened and has 4 layers instead of 6
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What two arteries supply blood to the brain?
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Internal carotid (anterior) and vertebral arteries (posterior)
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What do the verterbral arteries join to form?
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The basilar artery
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The internal carotid and basilar arteries join to form.....
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The circle of willis
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What artery branches off the verterbral arteries?
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The posterior inferior cerebellar artery (PICA)
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Where does the anterior inferior cerebellar artery (AICA) branch from?
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The basilar artery
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What is the next branch off the basilar artery after the AICA?
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The superior cerebellar artery
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What is the next branch after the superior cerebellar artery?
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The posterior cerebral artery
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What branch does the posterior cerebral artery give off?
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The posterior communicating artery
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Where does the vertebral artery join the basilar artery?
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The medulla/pons junction
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What connects the anterior and posterior circulation?
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The posterior communicating artery
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What does the anterior cerebral artery supply?
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Most of the frontal and parietal lobes and the paracentral lobule
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What does the posterior cerebral artery supply?
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The posterior regions of the brain; the occipital lobe which includes the visual cortex; supplies the medial and inferior temporal lobe
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What supplies the bulk of the lateral surface of the brain?
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The middle cerebral artery
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What does the middle cerebral exit in order to supply the lateral surface of the brain?
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The Sylvian fissure
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If you have a stroke in the anterior cerebral artery, what will be affected?
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The legs and feet on the contralateral side
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If you have an infarct in the middle cerebral artery, what area will be affected?
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The face and hands of the contralateral side.
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What are the deep arteries branching off the MCA?
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The lenticulostriate arteries
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What do the lenticulostriate arteries supply?
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The basal ganglia and the internal capsule
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If you have an infarct in the lenticulostriate arteries, what will be affected?
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The internal capsule causing total weakness on the contralateral side
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What is the most common artery for stroke of the 3 major cerebral arteries?
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The middle cerebral artery
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What are the divisions of the MCA?
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The superior, inferior, and deep
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What will be affected if the infarct occurs at the most proximal part of the MCA?
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All 3 divisions would be affected---a stem infarct.
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What would be affected if you had an infarct in the left MCA superior division?
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Right face and arm weakness (upper motor neuron type) and Broca's aphasia
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What would be affected if you had an infarct in the right MCA stem?
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Prfound left hemineglect, left hemiplegia, left hemianesthesia
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What would be affected if there was an infarct in the ACA?
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Contralateral weakness and loss of sensation in the lower extremity because of damage to the paracentral lobule
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What would be affected if there was an infarct in the PCA?
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Loss of one visual cortex.....a stroke in the left PCA would result in loss of visual information from the right side of each eye's visual field (a right homonymous hemianopia)
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What are the regions between the ACA and the MCA and the MCA and the PCA called?
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Watersheds
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What happens if there is an infarct in the ACA-MCA watershed?
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The "Man in a Barrell" syndrome (motor and sensory lost in the trunk region)
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What area of the brain does the PICA supply?
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The medulla and cerebellum
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What area of the brain does the AICA supply?
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The pons and cerebellum
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What area of the brain does the superior cerebellar artery supply?
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The midbrain and cerebellum
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What area of the brain does the anterior spinal artery supply?
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Parts of the medulla
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What are the two major arteries that supply the spinal cord?
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The anterior and posterior spinal arteries
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What portion of the spinal cord does the anterior spinal artery supply?
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2/3
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What portion of the spinal cord does the posterior spinal artery supply?
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1/3
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What is a stoke?
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Sudden death of brain cells due to a lack of oxygen
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What is the 3rd leading cause of death in the US?
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Stoke
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What are the two possible forms of stoke?
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Hemorrhage (20%) and infarct (80%)
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What are small vessels infarcts usually called?
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Lacunar infarcts
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What are the 5 major signs of stroke?
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Numbess or weakness or the face, arm, or leg
Confusion, trouble speaking Trouble seeing Trouble walking, loss of balance Severe headache |
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What do all of the signs of stroke have in common?
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They are all SUDDEN in onset
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What can we treat patient's with if the stroke is diagnosed within 3 hours?
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TPA
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What is the penumbra?
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Area surrounding the infarct
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Are the cells in the penumbra apoptosing or necrosing?
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Apotosing
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Is necrosis rapid and passive or prolonged?
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Rapid and passive
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Does necrosis occur at high levels or low levels of excitotoxicity?
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high levels
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Does apoptosis occur at high levels or low levels of excitotoxicity?
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Low levels
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Is necrosis reversible or irreversible?
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Irreversible
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Is apoptosis reversible or irreversible?
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Potentially reversible
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What is glutamate excitotoxicity?
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Major mechanism causing cell death during ischemia
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What is the major excitatory neurotransmitter of the brain?
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Glutamate
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What glutamate receptor plays the "deadly" role in ischemic condition?
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NMDA receptor
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What is pyramidal decussation?
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Crossing over of neurons
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Where does decussation occur?
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At the medulla-spinal cord junction
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Where do 98% of upper motor neurons synapse?
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On interneurons
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How does a subarachnoid hemorrhage usually present?
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As "the worst headache of my life"
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How do patients with a subarachnoid hemorrhage usually present?
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Drowsy, confused, nuchal rigidity from blood irritating the meninges
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How are hemorrhages usually diagnosed?
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CT Scan
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Where do Berry aneurysms usually occur?
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At bifucation of vessels; anterior communicating, posterior communicating MCA birfucation, and bifurcation of the internal carotid in to MCA and ACA
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What do the three meningeal layers in the brain do?
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Serve as a protection
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What do the meninges include?
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Dura, arachnoid, and the pia
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What is the dura and what does it include?
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It is the hard outermost meninge and includes the falx cerebri and the tentorium cerebelli
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What is the falx cerebri?
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Divides the cerbral hemispheres
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What is the tentorium cerebelli?
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Hard tent shaped sheet that covers the cerebellum
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What is the arachnoid?
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A spider web like layer; CSF percolates over the brain
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What is the meningeal layer closet to the brain?
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The pia
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What causes a subarachnoid hematoma?
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A tear in the briding veins
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Where is the epidural space?
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Between the dura and the skull
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Where is the subdural space?
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Between the arachnoid and the pia
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Where is the subarachnoid space?
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Between the arachnoid and the pia
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What is significant about the subarachnoid space?
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It is filled with CSF and it is where the major blood vessels run in the brain
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What are the two major sites for hematoma formation?
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The epidural and subdural spaces
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What artery is involoved in epidural hematoma?
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Middle meningeal artery
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What does an epidural hematoma look like on CT scan?
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A lens-shaped biconvex hematoma; bleeds fast
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What does a subdual hematoma look like on CT scan?
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A crescent shape; bleeds slowly
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What is an uncal herniation?
|
When the uncus herniates through the tentorial notch
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What is the classic triad of symptoms due to an uncal herniation?
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"Blown" pupil due to damage to occulomotor nerve, hempleiga, and coma
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What part of the brain are the lateral ventricles located in?
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The forebrain; telencephalon
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What part of the brain is the 3rd ventricle located in?
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The diencephalon
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What part of the brain is the cerebral aqeuduct located in?
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The mesencephalon or midbrain
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What part of the brain is the 4th ventricle located in?
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The hind brain
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What are the different parts of the lateral ventricles?
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Frontal (anterior horn), Body, Temporal (inferior horn), and Occipital (posterior horn)
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What connects the lateral ventricles with the third ventricle?
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The Foramen of Monro
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What connects the 3rd ventricle with the 4th ventrcie?
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The cerebral aqueduct
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What produced the cerebral spinal fluid?
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Choroid plexus
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What does the choroid plexus produce?
|
CSF
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What kind of cells line the ventricles?
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Ependymal cells
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What ions make up the CSF?
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Mg, Cl, and K
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Is the ionic composition tightly controlled?
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Yes to maintain a healthy environment
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What happens to glucose levels in the CSF in bacterial meningitis?
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Glucose drops because bacteria eat all the glucose
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Is the protein elevated or low in bacterial meningitis?
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Low protein
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What is the pattern of flow of CSF?
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Choroid plexus, lateral ventricles, foramen of monro, 3rd ventricle, cerebral aqueduct, 4th ventrcile
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Where does CSF drain into?
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Arachnoid villi or granulations
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Where does CSF pool?
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In the cisterns and then flows through the subarachnoid space
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Where is a CSF for a lumbar puncture taken from?
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Lumbar cistern
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How much CSF does the choroid plexus produce per day?
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500 ml
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How much CSF is in the ventricular system?
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140 ml
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How much CSF is in the ventricles?
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25 ml
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Where is the remaining 335 ml of CSF located?
|
subarachnoid space
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What happens if the CSF is not absorbed of flow is obstructed and CSF builds up?
|
Hydrocephalus
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What are the 3 causes of development of hydrocephalus?
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Excess production of CSF
Obstruction of flow of CSF Failure to drain CSF properly |
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What is the most common cause of build up of CSF in the brain?
|
Obstruction of flow due to tumors, masses, adhesions, or congential causes
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What is communicating hydrocephalus?
|
Ventricles are working fine but CSF flow is obstructed in the subarachnoid space or not absorbed in the granulations
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What is noncommunicating hydrocephalus?
|
Obstruction of flow of CSF between the ventricles
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What is an example of noncommunicating hydrcephalus?
|
Dandy-Walker Syndrome--the exit foramina for the ventricles were not formed
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|
What is the blood brain barrier?
|
Barrier around the brain that limits what can enter the brain--minimizes infection
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What keeps things from entering the blood brain barrier?
|
Tight junctions between endotheilial cells just in capillaries of the brain
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What forms the blood brain barrier?
|
Endotheilial cells
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What reinforces the blood brain barrier?
|
Astrocytes form foot processes that surround the tight junctions
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Besides the blood brain barrier, what is the other type of barrier seen in the brain?
|
Between the choroid plexus and the CSF--choroid epithelial cells make tight junctions between themselves so that things need to be actively transported across the barrier
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Can the CSF freely penetrate the barriers?
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Yes--allows it to bathe the neurons and glia in the brain
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Are there astrocytes in the choroid plexus barrier?
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No
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Where are the regions in which the BBB is interrupted?
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Area postrema, pineal gland, and neurohypophysis
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Where is the area postrema?
|
4th ventricle--detects toxins that can cause vomitting
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What area is called the Chemotactic trigger zone?
|
The area postrema
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Where is the neurohypophysis?
|
In the pituitary gland--regulates and releases pituitary hormones
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What does the pineal gland do?
|
Releases melatonin that can regulate circadian rhythms
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What sugar will open the BBB?
|
Mannose
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What are neurons that respond directly to sensory stimuli called?
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Receptors
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At the site of the stimulus, what is the electrical potential induced called?
|
Receptor potential, local potential, or generator potential
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Is the receptor potential an action potential?
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No!!!! It is a graded potential
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Does the local potential travel retrograde or anterograde?
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Retrograde
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Will an action potential automatically be producded from a local potential?
|
No....only if the stimulus is stong enough
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Does the terminus contain volrage gated channels or stretch receptors?
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Stretch receptors
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What info does the CNS receive from the sensory stimulus?
|
Modality, intensity, duration, and location
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What is modality?
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Vision, hearing, touch, taste, smell
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Where is all sensory information relayed to? What is the one exception?
|
Thalamus
Olfactory system |
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What are the four distinct modalities (sensations)?
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Touch, proprioception, pain, and thermal
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What are the types of somatosensory receptors?
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Mechanorecptors, thermoreceptors, nociceptors
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What do mechanoreceptors respond to?
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Physical deformation--physical contact, blood pressure, stretching of the gut and bladder, pressure on the teeth
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What do thermoreceptors respond to?
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Temperature
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What do nociceptors respond to?
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Pain and damage
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Is the skin a uniform sensory surface?
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No--if we touch the skin with a cold probe we will fill cold only if there is a receptor in the spot of the stimulus
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What do free nerve endings sense?
|
Pain and temperature
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What do Pacini's corpuscle sense?
|
Pressure and touch
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What do Ruffini endings respond to?
|
Physical change-mechanoreceptors
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What type of fibers are 1A?
|
Proprioreceptors; Muscle spindle endings
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What type of fibers are 1B?
|
Gogli tendon organs
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What type of fibers are type 2?
|
Mechanoreceptors--Mesinner's corpuscles, merkel endings, and pacinian corpuscles
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What is another name for type 2 fibers?
|
A Beta
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What type of fibers are type 3?
|
Nocioceptors--sharp pain, cold, touch
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What is another name for the 3 fibers?
|
A delta
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What type of fibers are type 4?
|
Nocioceptors and thermoreceptors--slow pain, itch, heat
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Which fibers are the largest in diameter?
|
Type 1A
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Which fibers are myelinated?
|
All but type 4/C
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What is another name for type 4 fibers?
|
C
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Which fibers are non myelintaed?
|
C fibers; type 4
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What is the speed of conduction related to?
|
The axon's diameter
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The larger the diameter....
|
The faster the conduction
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Which nerves are affected in diabetic neuropathy?
|
Smaller nerves
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Which nerves are affected in chemotherapy in cancer patients?
|
Larger nerves
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The amplitude of the generator potential is proportional to....
|
The intensity of the stimulus
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What is the receptive field?
|
The portion of the skin directly innervated by the receptor terminals
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Which has a larger receptive field, the back or the fingertip?
|
The back
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Which is more densely innervated, the back or the fingertip?
|
The fingertip
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The more densely innervated....
|
The smaller the receptive field
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What is the territory innervated by each spinal nerve called?
|
Dermatome
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What do dermatomes do?
|
Help determine the location of a lesion
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|
What is the concept of two-point discrimination?
|
In order to feel a stimulus in two different places, the stimulus must be applied in two different receptive fields
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What is the size of the cortical area devoted to a particular region proportional to?
|
The number of inputs from that region
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Where does a pain and temperature afferent fiber synapse?
|
In the spinal cord
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|
The pain and temperature afferent fiber leaving the fingertip going to the spinal cord is what kind of neuron?
|
1st order neuron
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What does the pain and temperature afferent fiber synapse on in the spinal cord?
|
A projection interneuron
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A pain and temperature fiber leaving the spinal cord traveling through the medulla to the thalamus is what order neuron?
|
2nd order neuron
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A pain and temperature fiber leaving the thalamus and traveling to the somatosenosry cortex is what order neuron?
|
3rd order neuron
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|
Where does a mechanoreceptor afferent fiber first synapse?
|
In the medulla in the cuneate nucleus
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The mechanoreceptor afferent fiber leaving the finger traveling to the medulla is what order neuron?
|
1st order neuron
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Once a mechanoreceptor fiber synapses in the cuneate nucleus, what order neuron does it become?
|
2nd order neuron
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|
What order neurons cross over to the opposite side of the spinal cord?
|
2nd order neurons
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|
What do lamina I-VI correspond to?
|
The dorsal horn
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|
What laminae are important areas for pain and tempertaure processing?
|
Laminae I and II
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|
What are laminae I and II important for?
|
Processing pain and temperature information
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|
What is Lissauer's tract?
|
Where A delta and C fibers enter the spinal cord (pain and temperature fibers)
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|
What is the substantia gelatinosa?
|
Laminae II--receives afferent information from nonmyelinated and myelinated fibers
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|
What nucleus is located in Laminae III-VI?
|
Nucleus proprius
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|
What does the nucleus proprius do?
|
Integrates sensory input with information that descends from the brain
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|
What is Laminae VII?
|
The intermediate zone
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|
What spinal levels correspond with laminae VII?
|
T1-L2
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|
What nucleus is located in Laminae VII?
|
Clark's nucleus
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|
What does Clark's nucleus do?
|
Relays information about proprioception to the cerebellum
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|
What else besides Clark's nucleus is located in Laminae VII?
|
The intermediolateral nucleus
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|
What kind of neurons are located in the IML?
|
Preganglionic sympathetic neurons
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|
Where do the preganglionic sympathetic neurons synapse?
|
In the sympathetic ganglion
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|
What laminae comprise the ventral horn?
|
VIII and IX
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|
What do laminae VIII and IX correspond to?
|
The ventral horn
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|
What does laminae VIII contain?
|
Interneurons that regulate skeletal muscle contraction
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|
What do laminae IX do?
|
Innervate skeletal muscle
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|
What can a lesion in laminae IX lead to?
|
Flaccid paralysis
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|
Where is the phrenic nucleus located?
|
Laminae IX
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|
Which is more severe, injuring a single spinal nerve or a peripheal nerve?
|
Peripheal nerve because it is a group of spinal nerves joined together
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|
What section of the spinal cord would we see a brachial enlargement?
|
C8
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|
What section of the spinal cord would we see a lumbar enlargement?
|
L5
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|
Does the dorsal column get smaller or larger as we move down the spinal cord?
|
Smaller
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|
Does the lateral faniculus get smaller or larger as we move down the spinal cord?
|
SmallerB
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In a cross section of a spinal cord below T6, would we see one or two dorsal columns?
|
Only one dorsal column
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|
In a cross section of a spinal cord above t6, would we see one or two dorsal columns?
|
Two dorsal columns
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|
What does the posterior dorsal column pathway send to the brain?
|
Proprioception/mechanorecptors
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|
What fibers are involved in the dorsal column pathway?
|
AB and IA
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|
What are the two components of the dorsal column?
|
Fasiculis gracilis and fasiculis cuneatus
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|
Where is the first synapse in the dorsal column pathway?
|
In the medulla--either in the nucleus gracilis and nucleus cuneatus
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|
Where do 2nd orders neurons decussate in the dorsal column pathway?
|
In the caudal medulla
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|
When the 2nd order neurons decussate, what are they called?
|
The internal arcuate fibers
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|
Once they decussate, what are they called?
|
Medial lemniscus
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|
Are the axons in the medial lemniscus conveying contralateral or ipsilateral signals?
|
Contralateral
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|
Where do axons in the medial lemniscus synapse?
|
The VPL of the thalamus
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|
Where do 3rd order neurons in the dorsal column pathway synapse?
|
In the somatosensory cortex
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|
Are the axons in the caudal medulla ipsilateral or contralateral?
|
Ipsilateral
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|
|
Are the axons in the rostral medulla ipsilateral or contralateral?
|
Contralateral
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|
|
Where are cell bodies of 1st order neurons in the dorsal column pathway located?
|
In the DRG
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|
|
Where are cell bodies of 2nd order neurons in the dorsal column pathway located?
|
In the nucleus cuneatus or nuclues gracilis
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|
|
Where are cell bodies of 3rd order neurons in the dorsal column pathway located?
|
In the VPL of the thalamus
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|
|
What are the internal arcuate fibers doing?
|
They are decussating
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|
|
What does the anterolateral pathway convey?
|
Pain and temperature to the brain
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|
|
What is the tract of the ALS that specifically stops in the VPL of the thalamus?
|
The spinothalamic tract
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|
|
What is the tract of the ALS that goes to the reticular and limbic systems?
|
The spinoreticular tract
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|
|
What is the tract of the ALS that goes to the periaqueductal gray region?
|
The spinomesencephalic tract
|
|
|
Where do 1st order neurons of the ALS synapse?
|
In the sympathetic ganglion in the spinal cord
|
|
|
Where do 2nd order neurons of the ALS synapse?
|
In the VPL of the thalamus
|
|
|
Where do neurons in the ALS decussate?
|
In the anterior commissure
|
|
|
Where do neurons of the spinoreticular tract synapse?
|
In the intralaminar and mediodorsal nuclei
|
|
|
Where do fibers from the intralaminar nuclei project?
|
All over the cortex, including the limbic system, to wake it up
|
|
|
What does the spinoreticular pathway project?
|
The emotional and arousal aspects of pain
|
|
|
Where do fibers in the spinomesencephalic tract project?
|
The periaquductal gray region of the midbrain
|
|
|
What does fibers in the spinomesencephalic tract regulate?
|
Decreasing the sensation of pain
|
|
|
What tract controls what when you step on a sharp tack with your foot?
|
Your spinothalamic tract enables you to realize that something is sharp on your foot; your spinoreticular tract causes you to feel "ouch"; and your spinomesencephalic tract lead to pain modulation allowing you to think it feels better
|
|
|
What is going on in Brown-Sequard Syndrome?
|
Ipsilateral weakness and sensation and contralateral loss of pain and temperature
|
|
|
Where do touch and pressure afferents enter the brain?
|
Pons
|
|
|
Where do touch and pressure afferents synapse?
|
In the principal sensory nucleus--also called the main sensory trigeminal nucleus
|
|
|
After synpasing in the main sensory trigeminal nucleus, where do toch and pressure neurons go?
|
They decussate and form the trigeminal lemniscus
|
|
|
Where does the trigeminal lemniscus project its neurons to?
|
The VPM of the thalamus
|
|
|
After synapsing in the VPM of the thalamus, where do neurons go?
|
To the lateral side of the somatosensory cortex
|
|
|
Where do pain and temperature afferents synapse?
|
In the spinal trigeminal nucleus
|
|
|
What does the spinal trigeminal tract run adjacent with?
|
The spinal trigeminal nucleus
|
|
|
From where to where does the trigeminal pathway run?
|
Midbrain to C2
|
|
|
After synapsing in the spinal trigeminal nucleus, where do pain and temperature fibers go?
|
They decussate and asscend to the VPM of the thalamus where they synapse again
|
|
|
After synpasing in the VPM of the thalamus, where do pain and temperature afferents go?
|
To the lateral somtasensory cortex
|
|
|
What does the principal sensory nucleus mediate?
|
The tactile information--touch and pressure
|
|
|
What does the spinal trigeminal nucleus mediate?
|
The pain and temperature information
|
|
|
Where are proprioceptive repsonses mediated?
|
The trigeminal mesencephalic nucleus
|
|
|
What does the trigeminal mesencephalic nucleus develop from?
|
Nerual crest cells folding inward instead of outward
|
|
|
Where do senosry neurons from the mesencephalic nucleus go?
|
Sensory neurons go out through the trigeminal nerve to the mandible muscles to mediate the jaw jerk reflex
|
|
|
Where do touch and pressure afferents enter the brain?
|
Pons
|
|
|
Where do touch and pressure afferents synapse?
|
In the principal sensory nucleus--also called the main sensory trigeminal nucleus
|
|
|
After synpasing in the main sensory trigeminal nucleus, where do toch and pressure neurons go?
|
They decussate and form the trigeminal lemniscus
|
|
|
Where does the trigeminal lemniscus project its neurons to?
|
The VPM of the thalamus
|
|
|
After synapsing in the VPM of the thalamus, where do neurons go?
|
To the lateral side of the somatosensory cortex
|
|
|
Where do pain and temperature afferents synapse?
|
In the spinal trigeminal nucleus
|
|
|
What does the spinal trigeminal tract run adjacent with?
|
The spinal trigeminal nucleus
|
|
|
From where to where does the trigeminal pathway run?
|
Midbrain to C2
|
|
|
After synapsing in the spinal trigeminal nucleus, where do pain and temperature fibers go?
|
They decussate and asscend to the VPM of the thalamus where they synapse again
|
|
|
After synpasing in the VPM of the thalamus, where do pain and temperature afferents go?
|
To the lateral somtasensory cortex
|
|
|
What does the principal sensory nucleus mediate?
|
The tactile information--touch and pressure
|
|
|
What does the spinal trigeminal nucleus mediate?
|
The pain and temperature information
|
|
|
Where are proprioceptive repsonses mediated?
|
The trigeminal mesencephalic nucleus
|
|
|
What does the trigeminal mesencephalic nucleus develop from?
|
Nerual crest cells folding inward instead of outward
|
|
|
Where do senosry neurons from the mesencephalic nucleus go?
|
Sensory neurons go out through the trigeminal nerve to the mandible muscles to mediate the jaw jerk reflex
|
|
|
Where do touch and pressure afferents enter the brain?
|
Pons
|
|
|
Where do touch and pressure afferents synapse?
|
In the principal sensory nucleus--also called the main sensory trigeminal nucleus
|
|
|
After synpasing in the main sensory trigeminal nucleus, where do toch and pressure neurons go?
|
They decussate and form the trigeminal lemniscus
|
|
|
Where does the trigeminal lemniscus project its neurons to?
|
The VPM of the thalamus
|
|
|
After synapsing in the VPM of the thalamus, where do neurons go?
|
To the lateral side of the somatosensory cortex
|
|
|
Where do pain and temperature afferents synapse?
|
In the spinal trigeminal nucleus
|
|
|
What does the spinal trigeminal tract run adjacent with?
|
The spinal trigeminal nucleus
|
|
|
From where to where does the trigeminal pathway run?
|
Midbrain to C2
|
|
|
After synapsing in the spinal trigeminal nucleus, where do pain and temperature fibers go?
|
They decussate and asscend to the VPM of the thalamus where they synapse again
|
|
|
After synpasing in the VPM of the thalamus, where do pain and temperature afferents go?
|
To the lateral somtasensory cortex
|
|
|
What does the principal sensory nucleus mediate?
|
The tactile information--touch and pressure
|
|
|
What does the spinal trigeminal nucleus mediate?
|
The pain and temperature information
|
|
|
Where are proprioceptive repsonses mediated?
|
The trigeminal mesencephalic nucleus
|
|
|
What does the trigeminal mesencephalic nucleus develop from?
|
Nerual crest cells folding inward instead of outward
|
|
|
Where do senosry neurons from the mesencephalic nucleus go?
|
Sensory neurons go out through the trigeminal nerve to the mandible muscles to mediate the jaw jerk reflex
|
|
|
Where do touch and pressure afferents enter the brain?
|
Pons
|
|
|
Where do touch and pressure afferents synapse?
|
In the principal sensory nucleus--also called the main sensory trigeminal nucleus
|
|
|
After synpasing in the main sensory trigeminal nucleus, where do toch and pressure neurons go?
|
They decussate and form the trigeminal lemniscus
|
|
|
Where does the trigeminal lemniscus project its neurons to?
|
The VPM of the thalamus
|
|
|
After synapsing in the VPM of the thalamus, where do neurons go?
|
To the lateral side of the somatosensory cortex
|
|
|
Where do pain and temperature afferents synapse?
|
In the spinal trigeminal nucleus
|
|
|
What does the spinal trigeminal tract run adjacent with?
|
The spinal trigeminal nucleus
|
|
|
From where to where does the trigeminal pathway run?
|
Midbrain to C2
|
|
|
After synapsing in the spinal trigeminal nucleus, where do pain and temperature fibers go?
|
They decussate and asscend to the VPM of the thalamus where they synapse again
|
|
|
After synpasing in the VPM of the thalamus, where do pain and temperature afferents go?
|
To the lateral somtasensory cortex
|
|
|
What does the principal sensory nucleus mediate?
|
The tactile information--touch and pressure
|
|
|
What does the spinal trigeminal nucleus mediate?
|
The pain and temperature information
|
|
|
Where are proprioceptive repsonses mediated?
|
The trigeminal mesencephalic nucleus
|
|
|
What does the trigeminal mesencephalic nucleus develop from?
|
Nerual crest cells folding inward instead of outward
|
|
|
Where do senosry neurons from the mesencephalic nucleus go?
|
Sensory neurons go out through the trigeminal nerve to the mandible muscles to mediate the jaw jerk reflex
|
|
|
Where do motor neurons from the mesencephalic trigeminal nucleus travel to?
|
Through the trigeminal motor nucleus and goes to synapse on muscle in the mandible
|
|
|
Where are proprioception neurons located for the trigeminal nerve?
|
In the mesencephalic trigeminal nucleus
|
|
|
What is the order of travel for a touch and pressure neuron in the trigeminal nerve?
|
Enters pons and synapses in the prinicpal sensory nucleus
Decussate and 2nd order neuron travels as trigeminal lemniscus to the VPM of the thalamus The 3rd order neuron travels to the lateal somatosensory cortex |
|
|
What is the order of travel for a pain and temperature neuron in the trigeminal nerve?
|
Enters through the pons and travels down the spnial trigeminal tract
Synapses in the spinal trigeminal nucleus Decussates and 2nd order neuron travels up the trigeminal thalamic tract to the VPM of the thalamus 3rd order neuron travels to somtosensory cortex |
|
|
What is the most common reason for physician visits?
|
Pain
|
|
|
What does nocioception refer to?
|
The sensing of painful stimuli
|
|
|
What are the three categories of pain?
|
Normal/Physiological pain
Inflammatory pain Neuropathic pain |
|
|
What is physiological pain?
|
The normal situation--tissue damage activating a nocioceptor
|
|
|
What is inflammatory pain?
|
Amplification of a normal response
|
|
|
What is neuropathic pain?
|
Pain caused by injury processess in nerves and by local inflammation in nerves--diabetic neuropathy
|
|
|
What is the most important synpase in pain?
|
Nocioceptors activating the dorsal horn which starts the whole cascade
|
|
|
What is released in response to tissue injury?
|
ATP
Bradykinin Serotonin H+ Histamine Prostaglandins |
|
|
What does substance P do?
|
Increases capillary permeability and contributes to inflammation
|
|
|
Does activation of a nocioceptor always produce pain?
|
No, not necessarily
|
|
|
Can you have nocioceptor activity and pain both?
|
Yes
|
|
|
Can you have nocioceptor activity without pain?
|
Yes
|
|
|
Can you have pain in absence of nocioceptor activity?
|
Yes
|
|
|
In the normal situation, when does pain become painful?
|
Once it reaches a threshold
|
|
|
What is allodynia?
|
When a stimulus that is not usually painful is now
|
|
|
What is hyperalgesia?
|
Pain sensation increased in magnitude
|
|
|
What is the sensation of pain?
|
The activation of nocioceptors
|
|
|
What is the perception of pain?
|
What the patient "feels"
|
|
|
What is an example of allodynia?
|
Moving hairs, brushing or warming the skin are all perceived as painful
|
|
|
What causes hyperalgesia?
|
Sensitization of nocioceptive endings
|
|
|
What are mechanical nocioceptors?
|
Activated by stong mechanical stimulation--sharp objects
|
|
|
What are thermal nocioceptors?
|
Respond to extreme heat or cold
|
|
|
When is pain considered "heat pain?"
|
Above 45 degrees C
|
|
|
What are polymodal nocioceptors?
|
Respond to several different stimuli--mechanical, heat, and chemical
|
|
|
Does activation of a nocioceptor always produce pain?
|
No, not necessarily
|
|
|
Can you have nocioceptor activity and pain both?
|
Yes
|
|
|
Can you have nocioceptor activity without pain?
|
Yes
|
|
|
Can you have pain in absence of nocioceptor activity?
|
Yes
|
|
|
In the normal situation, when does pain become painful?
|
Once it reaches a threshold
|
|
|
What is allodynia?
|
When a stimulus that is not usually painful is now
|
|
|
What is hyperalgesia?
|
Pain sensation increased in magnitude
|
|
|
What is the sensation of pain?
|
The activation of nocioceptors
|
|
|
What is the perception of pain?
|
What the patient "feels"
|
|
|
What is an example of allodynia?
|
Moving hairs, brushing or warming the skin are all perceived as painful
|
|
|
What causes hyperalgesia?
|
Sensitization of nocioceptive endings
|
|
|
What are mechanical nocioceptors?
|
Activated by stong mechanical stimulation--sharp objects
|
|
|
What are thermal nocioceptors?
|
Respond to extreme heat or cold
|
|
|
When is pain considered "heat pain?"
|
Above 45 degrees C
|
|
|
What are polymodal nocioceptors?
|
Respond to several different stimuli--mechanical, heat, and chemical
|
|
|
What is referred pain?
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Pain that arises from nocioceptors in visceral structures but is felt at different sites
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What causes referred pain?
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The convergence of visceral cutaneous nocioceptors onto the same dorsal horn and the brain can't distinguish the difference
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What is the "Shut the Gate" theory of pain?
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After getting an injury, you rub the area which stimulates mechanorecptors; that fires the neuron that inhibts the dorsal horn
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What is a monosynaptic reflex?
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A synapse consisting of one sensory neuron and one motor neuron
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What are reflexes called when they involve several interneurons?
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Polysynaptic Reflex
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What are reflexes called that involve one sensory neuron and one motor neuron?
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Monosynaptic reflex
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What is a classic monosynaptic reflex?
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Deep tendon reflex
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What happens when the knee is tapped on with a reflex hammer?
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The muscle is stretched which alerts sensory receptors in the extensor muscle
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Once a muscle has been stretched, what happens next?
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The Ia afferents synapse directly on the alpha lower motor neurons causing contraction of the muscle that was stretched
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Besides synapsing on alpha lower motor neurons, what else do Ia afferents synpase on?
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Synapses on interneurons that will inhibit the antagonistic muscle, which is the flexor muscle
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What is the advantage of Ia afferents synapsing on inhibitory neurons?
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It ensures the flexor (antagonistic) muscle relaxes while the other one contracts
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What affect would cutting the dorsal root have on the spinal reflex?
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It would abolish it
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If there is no response to the knee jerk reflex, is there a sensory or motor problem?
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It could be a problem with both
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What are the two types of motor neurons in the brain and spinal cord?
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Alpha and gamma motor neurons
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What do the alpha neurons innervate?
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The extrafusal muscle fibers
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What muscle fibers actually do the contraction or flexion?
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The extrafusal muscle fibers
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What do the gamma fibers innervate?
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The intrafusal muscle fibers
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What is the funtion of the gamma motor neurons?
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Regulate the length of the intrafusal muscle fibers
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What do Ia afferents tell us about the muscle?
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The Ia provides information about the rate of change in the muscle; change in length
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What do the II receptors tell us about the muscle?
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Provide information that the muscle is actually being stretched; confirmation that it is happening
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What muscle do Ia and II synpase directly on?
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The homonymous muscle
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What keeps the muscle "poised" for action?
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The gamma motor neurons
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What are Golgi Tendon Organs?
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Encapsulated sensory endings located at the junction of tendon and muscle
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How are GTOs arranged to muscle fibers?
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In series
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What are GTOs excited by?
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A muscle tensing up or contracting
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What do GTOs provide information about?
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Muscle force
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Can GTOs inhibit motor neurons when the force is too great?
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Yes
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What is the autogenic inhibition or inverse myotactic reflex?
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When muscle force is too great, GTOs activate inhibitory neurons in the spinal cord that will inhibit the contracting muscle
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What are the inhibitory neurotransmitters?
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Glycine or GABA
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What is the flexion reflex?
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Allows us to quickly withdraw from a painful stimulus
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When is the flexion reflex activated?
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When a nocioceptor responds to a painful stimulus
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When nocioceptors are stimulated in the flexion reflex what happens
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Withdrawal of the limb from the source of pain by exciting the ipsilateral flexor muscles and inhibiting the ipsilateral extensor muscles
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What is the cross extension reflex?
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When the extensor muscles of the contralateral limb are stimulated to provide support for the ipsilateral side
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What is spinal shock?
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Reflexes are silent initally and then after recovery become over active
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After spinal shock, what happens to the reflexes if the spinal cord is still intact?
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Hyperreflexia and abnormal reflexes appear
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What is the Babinski sign?
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Fanning of the toes--not usually present after 1 year of life
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What does a positive Babinski sign tell us?
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That the corticospinal tract has been interrupted
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If peripheal cell bodies are destroyed, can regrowth occur?
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No
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Distal to the lesion, peripheal nerves regenerate by what kind of process?
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Wallerian degeneration
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What is Wallerian degeneration?
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As the distal segment degenerates, the myelin sheath surrounding it breaks down and is phagocytosed by infiltrating macrophage
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Do Schwann cells survive the breaking down of the myelin sheath?
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Yes--they dedifferntiate and become immature Schwann cells
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Where do the Schwann cells stay resident?
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In the Bands of Bunger
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The further away an injury occurs relative to the cell body.....
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The more likely it is to regenerate
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What does IL-1 stimulate?
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Schwann cells and nerve growth factor
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What is transneuronal damage?
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The loss of pre and post neuronal cells due to the loss of the neuron in between
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Why are peripheal nerves able to regenerate?
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Schwann cells
Macrophages Integrins/Fibronectin ECM |
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Why do CNS cells not regenerate like PNS?
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There is much less ECM, very little fibronectin and laminin, no Schwann cells
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What allows CNS axons to regrow?
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IN-1 antibody
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What does IN-1 do?
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Blocks the inhibitory protein in olidgodendrites preventing CNS axons from growing
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What happens to the astrocytes after injury to the CNS?
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Astrocytes proliferate and increase their expression of chondroitin sulfate proteoglycans
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What do chondroitin sulfate proteoglycans do?
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Inhibit axon growth
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What does chondroitinase do?
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Fosters nerve fiber growth by digesting scar tissue
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What do olfactory ensheathing cells do?
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Promote axon regrowth
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What is a condition that is often confused with Parkinson's seen in elderly causing confusion and incontinence?
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Normal hydrocephalus
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What laminae are the alpha and gamma motor neurons located?
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Laminae IX
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