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230 Cards in this Set
- Front
- Back
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Glia
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Support cells of nervous systen, 10-50 times more numerous than neurons
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Astrocytes
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a major type of glial cell - a component of the blood brain barrier
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Oligodendroglia
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a major type of glial cell - forms myelin, the substance of axonal sheaths. in CNS only (PNS is Schwann cells)
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Action potential
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the nerve impulse carried along the axon
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Dendrites
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receive stimulation from other neurons
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Synaptic vesicles
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where neurotransmitters are stored
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Presynaptic terminals
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where neurotransmitters are released
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Neurotransmitter receptors
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where neurotransmitters bind at the postsynaptic neuron, giving rise to either an excitatory or inhibitory response
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Action potential
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transient voltage change in a neuron
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Apoptosis
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a process that kills neurons to enhance the organization of specific neuronal pathways, called pruning
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Schwann cells
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myelin forming cells in the peripheral nervous system
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nodes of Ranvier
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short exposed segments of axon, conduction occurs from node to node via "saltatory conduction"
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glutamate
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most common excitatory neurotransmitter in the CNS
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GABA
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most common inhibitory neurotransmitter in the CNS
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acetylcholine
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main transmitter at neuromuscular junctions in the PNS
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acetylcholine and norepinephrine
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important neurotransmitters in autonomic nervous system
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dopamine
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present in midbrain, sustantia nigra, pars compacta, ventral tegmental area with projections to prefrontal cortex, striatum, limbic cortex,m amygdala
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serotonin
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present in midbrain and pons, raphe nuclei, projects to entire CNS
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three main divisions of brain
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hindbrain (rhombencephalon)
midbrain (mesencephalon) forebrain (telencephalon) |
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Hindbrain consists of
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metencephalon (pons and cerebellum) and
myelencephalon (medulla) |
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Midbrain consists of
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cerebal peduncles
midbrain tectum midbrain tegmentum |
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Forebrain consists of
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telencephalon and diencephalon
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Telencephalon consists of
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Cerebral hemispheres, including
cerebral cortex subcortical white matter basal ganglia basal forebrain nuclei |
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Diencephalon consists of
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thalamus
hypothalamus epithalamus |
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Ventricles
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Lateral ventricles
Third ventricle: situated in midline of diencephalon Fourth: lies within brainstem |
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Enlarged ventricles sign of
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cerebral deterioration
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Internal carotid artery branches into
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middle and anterior cerebral arteries
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anterior cerebral artery supplies
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anterior frontal lobe and medial regions of brain
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medial cerebral artery supplies
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lateral temporal, parietal, and posterior frontal lobes and sends branches deep into subcortical regions
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vertebral arteries join to form the
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basilar artery, which provides blood to the brain stem and cerebellum
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medulla oblangata
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corticospinal tract runs down it and crosses here
site of basic life maintaining centers for respiration, blood pressure, heartbeat |
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reticular formation
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runs from medulla oblongata to diencephalon
network of interwined and interconnecting cell bodies that connects with all majjor neural tracts contains many nerve centers |
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reticular activating system (RAS)
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part of the reticular formation that controls wakefulness and alertness
modulates through arousal of cerebral cortex |
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pons
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contains pathways for fivers running between cortex and cerebellum
lesions may cause motor, sensory, and coordination disorders |
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cerebellum
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damage causes problems of fine motor control, coordination, postural regulation, diziness, jerky eye movements
also a variety of nonmotor functions from projections through thalamus, can disrupt reasdoning, fluency, visuospatial, atention |
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midbrain
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includes major portion of RAQS
lesions associated with specific movement disabilities |
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thalamus
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small, paired oval structure lying along the right and left sides of the third ventricle
each half consists of eleven nuclei or more |
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thalamic nuclei have connections with
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cortex and are topographically organized
sensory nuclei are major sensory relay centers for all senses except smell and project to primary sensory cortices |
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termination site for ascending RAS
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thalamus
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dorsomedial nucleus of the thalamus
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established role in memory (Korsakoff's)
extensive reciprocal connections with prefrontal cortex |
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mamillothalamic tract
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connects mammillary bodies with thalamus, lesions needed here to cause memory deficits in addition to thalamus
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mammillary bodies
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small structures at posterior part of hypothalamus involved in information correlation and transmission to the thalamus which wends projects on a pathway to prefrontal cortex and medial temporal lobe
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bilateral diencephalic lesions lead to
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korsakoff's syndrome
disturbance in time sense lack appreciation of deficits |
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fornix
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central forebrain structure that links the hippocampal and the mammilothalamic areas of the limbic system
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lesions to fornix
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recording of ongoing events may be impaired
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hypothalamus
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regulates physiologically based drives such as appetite, sexual arousal, and thirst
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basal ganglia
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situated at base of cerebral hemispheres, a number of nuclear masses, includes caudate, putamen, and globus pallidus.
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basal ganglia connections
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cerebral cortex projects directly to the caudate and putamen
globus pallidus and substantia nigra project back to cerebral cortex through the thalamus |
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neostriatum
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caudate and putamen
key component of procedural memory system |
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basal ganglia influence
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all aspects of motor control
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diseases of basal ganglia characterized by
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abnormal involuntary movements at rest
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nucleus basalis of Meynert
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small basal forebrain structure lyig partly within and partly adjacent to basal ganglia
important source of cholinergic neurotransmitters |
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loss of neurons in nucleus basalis of Meynert implicated in
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learning. loss of neurons here occurs in degenerative dementing disorders in which memory impairment is a prominent feature
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limbic system includes
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amygdala
cingulate gyrus hippocampus |
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limbic system has important role in
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emotion
motivation memory |
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amygdala
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small structure located deep in temporal lobe
important role in emotional processing learning |
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amygdala has rich connections with
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hypothalamus, so intimately involved with vegetative and protective drive states, movement patterns, and associated emotional responses
also has direct connections to olfactory bulbs |
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damage to amygdala
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associated with hypersexuality
diminished aggressive capacity |
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removal of amygdala
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apathetic, showing little spontaneity, creativity, or affective expression
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kluver bucy syndrome
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bilateral destruction of the amygdala and uncus
lose capacity to learn and make conceptual distinctions, eat excessively and indiscriminately, may become hypersexual, indiscriminately so |
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uncus
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small front end of innter temporal lobe fold
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cingulate gyrus
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located in medial aspect of hemispheres above corpus callosum
important influences on attention and emotional behavior |
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fornix
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paired, arch-shaped white matter structure that connects thehippocampal formation to the hypthalamus and septal nuclei
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hippocampus
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major component of memory system, critical for learning new memories
rus within inside fold of each temporal lobe |
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bilateral damage to hippocampus
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severe anterograde amnesia (H.M.)
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damage to left hippocampus
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impaired verbal memory
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damage to right hippocampus
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impaired recognition and recall of "complex visual and auditory patterns to which a name cannot be readily assigned."
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white matter
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densely packed conduction fibers that transmit neural impulses between cortical points within a hemisphere (association fibers), between hemispheres (commissural fibers) or between cerebral cortex and lower centers (projection fibers)
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central sulcus also called
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fissure of Rolando
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homonymous hemianopia
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blindness in one side of both visual fields
results from damage to one side of occipital cortex right damage leads to right visual field cut |
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scotoma
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area of blindness within the visual field
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planum temporale
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posterior portion of the superior surface of the temporal lobe
involved in auditory processing, larger on left side |
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catastrophic reaction
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most associated with left hemisphere lesions
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indifference reaction
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most associated with right hemisphere lesions
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gyri
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ridges
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sulci
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shallow clefts
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two major fissures
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central sulcus (fissure of Rolando) and
lateral fissure (Sylvian fissure) |
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immediately in front of central sulcus
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precentral gyrus
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precentral gyrus contains
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primary motor cortex
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entire area in front of central sulcus
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precentral or preroandic area
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behind central sulcus
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primary somesthetic cortex
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visual pathway
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retina through lateral geniculate nucleus of thalamus to primary visual cortex
lesion anywhere can produce a homonymous hemianopia |
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Anton's syndrome
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denial of blindness
typically lesions are bilateral and involve occipital lobe |
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lesions to visual association areas lead to
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visual agnosias
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apperceptive visual agnosia
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can't synthesize what they see
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associative visual agnosia
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can perceive but cannot recognize
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Balint's syndrome, aka
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simultaneous agnosia or simultanagnosia - inability to perceive more than one object or point in space at a time
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unilateral sensory or spatial neglect
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imperception of stimuli
typicall occurs with right parietal lobe and occipoital lobe damage |
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prosopagnosia
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can occur when cortex on undersides of occipital and temporal lobes are damaged bilaterally
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two visuoperceptual systems
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parieto-occipital: where
temporo-occipital: what |
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longitudinal or sagittal fissure
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cleft separating the hemispheres
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apraxia
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inability to conceptualize, plan, and execute motor movements
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constructional disorders
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predominantly parietal lobe disabilities that appear either left or right side
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Gerstmann's syndrome
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acalculia
right-left confusion finger agnosia dysgraphia lesion in inferior parietal lobe |
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primary auditory cortex located
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upper posterior transverse folds of temporal cortex (Heschel's gyrus) , for the most part tucked within the Sylvian fissure
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superior temporal gyrus receives input from
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medial geniculate nucleus of thalamus
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pure word deafness
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inbility to comprehend spoken words despite intact hearing, speech production, reading ability, and recognition of nonlinguistic sounds
occurs ostly with left temporal lesions |
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auditory agnosia
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inability to recognize auditorily presented environmental sounds independent of any deficit in procssing spoken language
primarily associated with right temporal lobe lesion |
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phonagnosia
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inability to recognize familiar voices
right parietal lobe lesion |
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Wernicke's aphasia also called
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sensory aphasia
fluent aphasia jargon aphasia |
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Wernicke's aphasia
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can understand little of twhat they hear, but motor production of speech remains intact (although they primarily produce nonsense)
many are anosognosic |
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Anosognosia
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inappreciation of deficits
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dysnomia
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difficulty retrieving words
lesion in left temporal lobe |
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olfactory cortex located
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medial temporal lobe near the tip and involves the uncus
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olfactory cortex receives input from
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olfactory bulb at base of frontal lobe
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frontal release signs
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aka "primitive" reflexes, normal in infants
grasp, root, suck, and snout seen in frontal lobe lesions |
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extinction
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stimulus perceived normally when presented to one side, but not perceived to side opposite lesion when presented bilaterally
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palniopsia
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persistence or reappearance of an object viewed earlier
frontal lobe lesions |
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internal jugular veins
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provides almost all venous drainage from brain
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spinal cord receives blood supply from
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anterior spinal artery
posterior spinal arteries |
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prefrontal damage leads to
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problems starting
problems stopping difficulties shifting concrete attitude deficient self-awareness |
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dysdiadochokinesia
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abnormal alternating movements
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romberg test
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patient closes eyes with feet close together, watch for sign of imbalance
lesion in proprioceptive system |
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stereognosis
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identification of objects by touch
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graphesthesia
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identify numbers and leters being traced on palm
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Battle's sign
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dark purple ecchymoses visible in skin overlying mastoid procseses due to base of skull fracture
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foramen magnum
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largest foramen at base of the skull
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cervicomedullary junction
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point where spinal cor meets the medulla, occurs at level of foramen magnum
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anterior fossa
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contains frontal lobe
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middle fossa
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contains temporal lobe
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posterior fossa
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contains cerebellum and brainstem
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meninges
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pia
arachnoid dura |
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falx cerebri
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point where dura folds into cranial cavity, separates right and left cerebral hemispheres
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tentorium cerebelli
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tentlike sheet of dura that covers the upper surface of the cerebellum
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tentorial notch
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where the midbrain passes through the tentorium cerebelli
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dura is composed of
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two tough, fibrous layers; periosteal (adherent to inner surface of skull) and meningeal layer (fused except at falxes)
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epidural space
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potential space located between inner surface of the skull and tightly adherent dura
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middle meningeal artery
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enters skull through foramen spinosum and runs in epidural spoace between dura and skull, it's a branch of the external carotid artery
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subdural space
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potential space between inner layer of dura and loosely adherent arachnoid
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bridging veins located
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in the subdural space
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bridging veins do what
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drain the cerebral hemispheress and pass through subdural space en route to several large dural venous sinuses
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dural sinuses are
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large venous channels that lie enclosed within the two layers of dura
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dural sinuses drain blood via the
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sigmoid sinuses, which ultimately reach the internal jugular veins
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subarachnoid space
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CSF fluid filled space between arachnoid and pia
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intraventricular foramen of Monro
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passage between third ventricle and the lateral ventricles
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cerebral aqueduct (also called aqueduct of Sylvius)
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passage between third ventricle and the fourth ventricle
travels through the midbrain |
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lateral foramina of Luschka
midline foramina of Magendie |
CSF leaves ventricular system via these foramena in the fourth ventricle
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arachnoid granulations
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where CSF is ultimately reabsorbed into dural venous sinuses, thus back into the blood stream
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cisterna magna aka cerebellomedullary cistern
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located beneath cerebellum near foramen magnum
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fortification scotoma
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characteristic region of visual loss bordered by zigzagging lines, seen in migraine
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pseudotumor cerebri
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condition of unknown cause characterized by headache and elevated ICP with no mass lesions
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herniation
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displacement of nervous system structures so severely that they are shifted from one compartment to the other
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common symptoms and signs of elevated intracranial pressure
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headache
altered mental status, especially irritability and depressed level of alertness and attention (most important) nausea and vomiting papilledema visual loss diplopia (double vision) Cushing's triad |
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Cushing's triad
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hypertension, radycardia, and irregular respirations
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Papilledema
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engorgement and elevation of the optic disc
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transtentorial herniation (or tentorial herniation)
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herniation of the temporal lobe, particularly the uncus, through the tentorial notch
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signs of uncal herniation
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blown pupil (caused by compression of CNIII)
hemiplegia(caused by compression of cerebral peduncles) coma (caused by compression of the reticular formation) |
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tonsillar herniation
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herniation of the cerebellar tonsils through the foramen magnum, often leads to respiratory arrest and death
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petechial hemorrhages
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small spots of blood in the white matter, seen after TBI
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epidural hematoma
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occurs in space between dura and skull
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epidural hematoma usually caused by
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rupture of middle meningeal artery due to fracture of temporal bone by head trauma
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subdural hematoma
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occurs in space between dura and arachnoid
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subdural hematoma usually caused by
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rupture of briding veins, which are particularly vulnerabl to shear injury
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subarachnoid hemorrhage
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in CSF filled space between archnoid and pia, which contains the major blood vessels of the brain
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subarachnoid hemorrhage has two broad causes
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nontraumatic (spontaneous)
traumatic |
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nontraumatic subarachnoid hemorrhage
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presents with "worst headache of my life"
occurs as rupture of arterial aneurysm in subarachnoid space |
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traumatic subarachnoid hemorrhage
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bleeding into the CSF from damaged blood vessels, associated with traumatic injuries
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coup injury
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injury on side of impact
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contrecoup injury
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injury opposite side of impact
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arteriovenous malformation (AVM)
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congenital abnormalities in which abnormal direct connections between arteries and veins, often forming a tangle of abnormal blood vessels
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communicating hydrocephalus
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impaired CSF reabsorption in the arachnoid granulations, obstruction of flow in the subarachnoid space, or (rarely) excess CSF production
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noncommunicating hydrocephalus
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obstruction of flow within the ventricular system
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Parinaud's syndrome
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in hydrocephalus - "setting sun" sign, consists of bilateral deviation of the eyes downwrd and inward
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ventriculoperitoneal shunt
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shunt tube goes from lateral ventricle to peritoneal cavity of the abdomen
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normal pressure hydrocephalus
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condition sometimes seen in elderly, characterized by chronically dilated ventricles, present with clinical triad of gait difficulties, urinary incontinence, and mental decline
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anterior communicating artery
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connection between anterior cerebral arteries
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posterior communicating arteries
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connection between internal carotids to posterior cerebral arteries, thereby connecting anterior and posterior circulations
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posterior cerebral arteries
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arise from top of basilar artery
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two major branches of anterior cerebral artery
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pericallosal and callosomarginal, feeds anterior medial surface including medial sensorimotor cortex
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middle cerebral artery feeds
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depths of sylvian fissure
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posterior cerebral artery feeds
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inferior and medial temporal lobes
medial occipital cortex |
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left MCA superior division infarct
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right face and arm weakness, nonfluent aphasia
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left MCA inferior division infarct
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fluent aphasia, right visual field deficit, motor findings usually absent
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right MCA superior division infarct
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left face and arm weakness
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right MCA inferior division infarct
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profound left heminegelect, left isual field and somatosensory eeficits
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left ACA infarct
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right leg weakness, right leg sensory loss, grasp reflex, frontal lobe behavioral abnormalities, larger infarcts may cause right hemiplegia
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right ACA infarct
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left leg weakness, left leg sensory loss, grasp reflex, frontal lobe behavioral abnormalities, left hemineglect, larger infarcts may cause left hemiplegia
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left PCA infarct
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right homonymous hemianopia
could cause alexia without agraphia larger infaracts could include thalamus and internal capsule and may cause aphasia, right hemisensory loss and right hemiparesis |
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right PCA infarct
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left homonymous hemianopia
larger infarcts including thalamus and internal capsule may cause left hemisensory loss and left hemiparesis |
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large MCA infarcts often have gaze preference
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toward the side of the lesion
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transient ischemic attack
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typically lasts about 10 minutes
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two types of ischemic stroke
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embolic (piece of material, like blood clot) is formed in one place and then travels through bloodstream to lodge in and occlude a blood vessel supplying the brain
thrombotic infarct - blood clot formed locally on blood vessel wall |
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lacunar infarcts
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small vessel infarcts
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superficial veins primarily drain into
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superior sagittal sinus and cavernous sinus
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deep veins primarily drain into
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great vein of Galen
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ultimately all veins drain into
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internal jugular veins
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nuchal rigidity
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often a sign of meningeal irritation caused by imflammation, infection, or hemorrhage in the subarachnoid space
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sign of subarachnoid hemorrhage
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worst headache of my life
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lateral geniculate nucleus of thalamus
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projects to the primary visual cortex, receives info from retinal ganglion cells in optic tracts
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midline of cererbellum called
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vermis
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cerebellar peduncles
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form walls of fourth ventricle
three of them |
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basal ganglia
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collection of gray matter nuclei deep within white matter of cerebral hemispheres
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caudate and putamen
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neostriatum or striatum
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inputs to basal ganglia
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cerebral cortex
motor control |
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outputs from basal ganglia
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ventral lateral and ventral anterior nuclei of thalamus
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upper motor neuron lesions cause
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slow, clumsy, stiff movements and hyperreflexia (spasticity)
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movement disorders caused by basal ganglia damage are
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contralateral to the lesion
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bradykinesia
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slowed movement
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hypokinesia
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decreased amount of movement
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akinesia
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absence of movement
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rigidity
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increased resistance to passive movement of a limb
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cogwheel rigidity
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ratchetlike interruptions in tone that can be felt as the limb is bent
often seen in parkinsonian disorders |
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dystonia
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abnormal, often distorted positions of limbs, trunk, or face that are more sustained or slower than in athetosis
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torticollis
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a focal dystonia which involves the neck muscles
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athetosis
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twisting movements of limbs, face, and trunk
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choreoathetosis
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merging of athetoid movements with choreic movements, which are faster
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chorea
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nearly continuous involuntary ovements that have fluid or jerky, constantly varying quality
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myoclonus
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fastest of movement disorders, sudden rapid muscular jerk
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tremor classification
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resting (parkisonian)
postural (essential tremor) intention (cerebellar) |
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Huntington's disease gene located on
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chromosome 4, too many CAG repeats
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arcuate fasciculus
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subcortical white matter pathway by which Broca's and Wernicke's communicate with each other
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dysarthria
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motor disorder of speech
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aphemia
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verbal apraxia
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most common etiology of Broca's aphasia
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infarct in left middle cerebral artery superior division
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quality of Broca's aphasia
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effortful, lack of prosody, telegraphic, lkack of grammatical structure and monotonous sound
repetition impaired |
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commonly associated features with Broca's
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dysarthria
right hemiparesis affecting face and arm more than leg |
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quality of Wernicke's aphasia
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impaired comprehension
empty, meaningless, full of nonsensical paraphasic errors impaired repetition |
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commonly associated features with Wernicke's
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contralateral visual field cut, esp of right upper quadrant
often unaware of deficit |
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conduction aphasia
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impaired fluency
impaired comprehension impaired repeittion |
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transcortical aphasias
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repetition is spared
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transcortical sensory aphasia
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normal fluency
impaired comprehension intact repetition |
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transcortical motor aphasia
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impaired fluency
normal comprehension intact repetition |
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Gerstmann's syndrome localization
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dominant inferior parietal lobule in region of angular gyrus
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Gerstmann's syndrome
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agraphia
acalculia right-left isorientation finger agnosia |
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corpus callostomy may cause
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agraphia of left hand
inability to name objects placed in left hand with eyes closed iability to read in left hemifield |
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hemineglect most often seen with lesions where
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in right parietal or right frontal lobes
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anosodiaphoria
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aware of deficits but show no emotion or distress about it
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hemiasaomatognosia
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patients deny that left half of body belongs to them
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Anton's syndrome
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aka cortical blindness
caused by bilateral lesions of primary visual cortex completely unaware of deficit |
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prosopagnosia lesion in
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bilateral inferior occipitotemporal cortex, aka fusiform gyrus
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