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143 Cards in this Set
- Front
- Back
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embryological dvlp of CAN
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sheet of ectodermal cells that fols over to form the neural tube
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prosencephalon
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forebrain
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mesencephalon
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midbrain (cerebral peduncles, tectum, tegmentum)
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rhombencephalon
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hindbrain
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forebrain divisions
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telencephalon and diencephalon
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telencephalon
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cerebral hemispheres
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diencephalon
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thalamus, hypothalamus, epithalamus
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midbrain
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relatively short and narrow region connecting the forebrain and hindbrain
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hindbrain
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pons, cerebellum, medulla
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metencephalon
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pons, cerebellum
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myelencephalon
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medulla
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what does the brainstem control
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basic body fxns: respiration, BP, heart rate
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where is CSF made
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choroid plexus
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CSF circulation
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lateral ventricles to third ventricle, to fourth ventricle, to outside of brain and spinal cord
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meninges
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pia, arachnoid, and dura
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where is CSF absorbed into the venous system
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btwn the arachnoid and pia mater
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where does the 90 bend occur btwn spinal cord and forebrain in humans
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region of midbrain-diencephalic jxn
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where are bipolar neurons often found
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sensory like vision or olfaction
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pseudounipolar
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processes initially fused, then split to produce two long axons (ex dorsal root ganglion sensory neurons)
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where do unipolar neurons occur
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invertebrates
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how long does an AP last
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~1 ms; propagate up to 60 m/s
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myelin-forming glial cells in the CNS
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oligodendrocytes
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myelin-forming glial cells in the PNS
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Schwann cells
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what are located in the nodes of Ranvier
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Voltage gated ion channels concentrated; saltatory conduction
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neuromodulation
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slower time scale of regulating neuron via signaling cascades, growth, other fxns
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most common excitatory neurotransmitter
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glutamate
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most common inhibitory neurotransmitter
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GABA (gamma-aminobutyric acid)
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cerebral cortex
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surface of cerebral hemispheres covered by a unique mantle of gray matter
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nuclei
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large clusters of gray matter deep in cerebral hemispheres and brainstem
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examples of nuclei
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basal ganglia, thalamus, cranial nerve nuclei
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spinal cord white/gray matter
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white outside gray inside
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varous names for white matter tracts in the CNS
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tract, fascicle, lemniscus, bundle
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commisure
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white matter pathway that connects identical structures on right and left sides of the CNS
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afferent
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pathwyas carrying signals toward a structure; arrive
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efferent
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carrying signals away from a structure; exit
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general orientation of motor and sensory systems
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motor generally ventral/anterior and sensory dorsal/posterior
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where does the spinal cord typically end
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L1 or L2
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what is below the spinal cord
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cauda equina
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What nerves/cranial nerves have parasympathetics
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CN III, VII, IX, and X; S2-4
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where does sympathetic division arise
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T1 to L2
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what does enteric nervous system control
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peristalsis and GI secretions
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sulci
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numerous infoldings or crevices of brain
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gyri
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bumps or ridges btwn sulci
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four major lobes of the cerebral hemispheres
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frontal, temporal, parietal, occipital
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where do the frontal lobes extend back to
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central sulcus of Rolando
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what are the frontal lobes separately inferiorly and laterally from the temporal lobes by
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Sylvian fissure aka lateral fissure
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fissure
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refers to deep sulci
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parietal lobe boundaries
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anteriorly by central sulcus, no sharp demarcation from temporal lobes or occipital lobes viewed from lateral side
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parieto-occipital sulcus can be viewed how
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viewed from medial aspect
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insular cortex
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additional region of cortex buried within depth of Sylvian fissure
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what are the lips of frontal and parietal cortex covering the insular cortex called
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frontal and occipital operculums (means covering/lid in latin)
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what fissue divides the two cerebral hemispheres
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interhemisphereic fissure aka longitudinal fissure
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corpus callosum
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large C-shape band of white matter that connects homologous areas in the two hemispheres
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gyrus running in front of the central sulcus
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precentral gyrus
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most anterior portion of the parietal lobe behind the central sulcus
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postcentral gyrus
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what parietal lobule surrounds the end of the Sylvian fissure
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supramarginal gyrus
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What parietal lobule surrounds the end of the superior temporal gyrus
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angular gyrus
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what does the corpus callosum consist of
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rostrum, genu, body, splenium
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what gyrus surrounds the corpus callosum
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cingulate gyrus (means girdle/belt)
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region surrounding the central sulcus
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paracentral lobule
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portion of the medial occipital lobe below the calcarine fussure
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lingula
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portion of the medial occipital lobe above the calcarine fussure
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cuneus (wedge)
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where is the primary visual cortex
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occipital lobes along the banks of a deep sulcus called the calcarine fissure
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where is the primary auditory cortex
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transverse gyri of Heschl inside the Sylvian fissure on the superior surface of each temporal lobe
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homunculus
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somatotopic maps on the cortex (either sensory or motor)
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neocortex
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majority of the cerbral cortex-consists of 6 layers from the surface inwards
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Layer I consists of
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dendrites of neurons from deeper layers and axons
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Layer II and III consist of
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neurons that project mainly to other areas of cortex
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Layer IV consists of
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receives majority of inputs from thalamus
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Layer V consists of
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projects mostly subcortical structures other than thalamus (brainstem, spinal cord, basal ganglia)
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Layer VI consists of
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projects primarily to the thalamus
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primary motor cortex job
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large efferent projections to brainstem and spinal cord to control movement; little sensory info from thalamic relay centers
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primary motor cortex layers
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V is thiker and has many more cell bodies that IV
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primary visual cortex layers
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IV contains many cell bodies and layer V is relatively cell poor
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Brodman classification
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52 cytoarchitectonic areas that correlate fairly well with fxn
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Name for Layer 1
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molecular layer
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Name for Layer 2
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small pyrimidal layer
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Name for Layer 3
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medium pyrimidal layer
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Name for Layer 4
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granular layer
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Name for Layer 5
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large pyramidal layer
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Name for Layer 6
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polymorphic layer
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most important motor pathway
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corticospinal tract
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where do 85% of the fibers in the corticospinal tract cross
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jxn between medulla and spinal cord (pyramidal decussation)
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lesions above the pyramidal decussation produce
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contralateral weakness
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lesions below the pyramidal decussation produce
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ipsilateral weakness
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upper motor neurons
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project from cortex down to the spinal cord or brainstem; UMNs
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Lower motor neurons
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located in anterior horns of central gray matter of the spinal cord or in brainstem motor nuclei
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where do LMNs travel
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out of the CNS via anterior spinal roots or cranial nerves to reach muscle cells in the periphery
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lesions in cerebellum lead to
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disorders in coordination and balance (ataxia)
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lesions in basal ganglia cause
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hypokinetic movement disorders (Parkinsonism) and hyperkinetic movement disorders (huntingtons's)
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Parkinsonism movements
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movements are infrequent, slow, and rigid
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Huntinton's movements
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dancelike involumtary movements
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Why do lesions in cerebellum and basal ganglia cuase motor impairments
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modulate output of the corticospinal and other descending motor systems
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major relay center for signals traveling to cerebral cortex
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thalamus
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proprioception
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limb or joint position sense
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Posterior column pathways transmit
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convey proprioception, vibration sense, and fine discriminative touch
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Antereolateral Pathways transmit
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convey pain, temperature sense, and crude touch
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where are the primary sensory neuron cell bodies located
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dorsal root ganglia (bifurcating neurons)
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where does the posterior column pathway cross over
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synapse in dorsal column nuclei in medulla which cross over to the other side of the medulla, synapse in thalamus, and go to primary somatosensory cortex in postcentral gyrus
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where does the anterolateral pathway cross over
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enter spinal cord and synapse in gray matter, cross over and ascend, synapse in thalamus, continues to primary somatosensory cortex
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thalami location
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grey matter structures located deep within the cerebral white matter just above brainstem and behind basal ganglia; egg-shaped with posterior ends angled outward
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what does hypothalamus regulate
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autonomic, neuroendocrine, limbic, and other circuits
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what is the epithalamus
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several small nuclei including the pineal body, habenula, and parts of the pretectum
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monosynaptic stretch reflex
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reflex arc that provides rapid local feedback for motoe control
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what does a reflex arc start with
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muscle spindles-detect amount and rate of stretch in muscles
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where do muscle spindles send info
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distal processes of sensory neurons, then to dorsal roots into spinal gray matter
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what occurs to signal once in spinal cord gray matter
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multiple synapses: 1) directly to LMNs in anterior horn 2) excitatory and inhibitory interneurons (which may synapse on LMNs)
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are there descending pathways that modulate the activity of the stretch reflex
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yes; if absent the reflex may be hyperactive or hypoactive
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what does the brainstem connect to
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diencephalon rostrally, cerebellum dorsally, and spinal cord caudally
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reticular formation location
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throughout the central portions of the brainstem from medulla to midbrain
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reticular formation in medulla and pons
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tends to be involved in mainly motor and autonomic fxns
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rostral reticular formation involvement
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level of consciousness by modulation of thalamic activity
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what other areas are important for maintaining consciousness
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cortical, thalamic, and other forebrain networks
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limbic system includes
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certain cortical areas in medial and temporal lobes, anterior insula, inferior medial frontal lobes, and cingulate gyri; hippocampal formation and amygdala, several nuclei in medial thalamus, hypothalamus, basal ganglia, septal area, and brainstem
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what are the areas of the limbic system connected by
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fornix and a variety of other pathways
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fornix
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paired, arch-shaped white matter structure that connects the hippocampal formation to the hypothalamus and septal nuclei
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lesions in limbic system can cause
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deficit in consolidation of immediate recall into longer-term memories
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where do epileptic seizures most commonly arise from
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limbic structure of the medial temporal lobe
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where is unimodal association cortex generally located
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adjacent to primary motor or sensory area
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heteromodal association cortex fxn
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integrate fxns from multiple sensory and/or motor modalities
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where is language usually perceived first
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primary auditory cortex in superior temporal lobe for speech or primary visual cortex when reading
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where do cortical-cortical association fibers convey information
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to Wernicke's area in the dominant hemisphere (usually L)
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lesions in Wernicke's area cause
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deficit in language comprehension (recaptive or sensory aphasia or Wernicke's aphasia)
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Broca's area location
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frontal lobe (L hemisphere) adjacent to areas of primary motor cortex involved in moving the lips, tongue, face, and larynx
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lesion in Broca's area causes
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deficit in production of language; expressive or motor aphasia
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lesions in inferior parietal lobule in L hemisphere can produce
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difficulty with calculations, right-left confusion, inability to identify figers by name (finger agnosia), difficulties with written language; called Gertmann's syndrome
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where does motor planning occur
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in diffuse areas of cortex
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apraxia
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abnormalities in motor conceptualization, planning, and execution
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lesions in parietal lobe, especially non-dominant hemisphere cause
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distortion of percieved space and neglect of contralateral side
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anosognosia
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unawareness of a deficit
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frontal release signs
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primitive reflexes normal in infants (grasp, root, suck, snout reflexes)
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perseverate
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repeat single action over and over without moving on to next one
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abulic
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Loss or impairment of the ability to make decisions or act independently
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magnetic gait
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feet shuffle close to floor
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prosopagnosia
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inability to recognize faces
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achromatopsia
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inability to recognize colors
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palinopsia
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persistance or reappearance of an object viewed earlier
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anterior blood supply to brain
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internal carotids
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what forms the basilar artery
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the two vertebral arteries
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venous drainage for brain
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almost entirely by internal jugular veins
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where does the spinal cord receive blood supply
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anterior spinal artery along ventral surface and paired posterior spinal arteries along R and L dorsal surfaces
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what supplies anterior and posterior spinal arteries in cervical region
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branches from vertebral arteries
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what supplies anterior and posterior spinal arteries in thoracic and lumbar regions
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radicular arteries arising from aorta
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