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157 Cards in this Set
- Front
- Back
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CNS
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Brain & Spinal Cord
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PNS
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spinal & cranial nerves transmit info to & from CNS
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Autonomic NS
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regulates visceral function
has components of CNS and PNS |
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Gyrus
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Brain ridge
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Sulcus
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Brain rooves
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three membranes surrounding the brain
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dura mater, arachnoid, pia mater
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3 segments of the brain
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cerebrum, cerebellum, brain stem
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Locations of the 4 ventricles
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2 lateral ventricles in each hemisphere
third between two thalami fourth between brainstem & cerebellum |
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Arteries that carry blood to the brain that meet in the Circle of Willis
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2 carotid arteries, 2 vertebral arteries
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How deoxygenated blood is carried back to the heart and lungs
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Venous sinuses return deoxygenated blood to the internal jugular veins in the neck
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The difference between neurons and glial cells
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glia support neurons
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Number of neurons in the brain
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100 billion
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Number of synapses for each neuron
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1000s
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The difference between gray matter vs. white matter
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(1) White matter myelinated axons, enables connectivity between brain areas
(2) Gray matter cell bodies and synapses |
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why white matter is white
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myelin
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Function of neurons
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bring sensory information from periphery, send motor signals from brain
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Soma
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houses nucleus & organelles
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dendrite
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short processes, receive input
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axons
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long process, sends output
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Summary of how information is transmitted between neurons
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Influx of sodium ions reverses polarity of axonal membrane, sends electrical action potential
At synapse (chemical) neurotransmitter, diffuses across synaptic cleft, binds to receptor, either depolarizes (excitatory stimulus) or hyperpolarizes (inhibitory stimulus) |
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Location and function of astrocytes
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star shaped
Location: both gray & white matter Function: support neurons, metabolic regulation of the microenvironment, respond to brain injury |
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Myelinating cells: location and function
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Oligodendrocytes: mainly in white matter, CNS
Schwann cells: PNS Function: speed up action potential |
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Function of microglia
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go to damaged areas, dispose of pathogens & debris
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Locations and functions of epyndemal cells
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Location: line ventricular system, choroid plexus
Function: form a secretory epithelium that produces CSF |
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Blood Supply - Consequences and timeline of events after interruption of oxygenation
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neurologic symptoms within seconds, irreversible neuronal damage and ultimately death within minutes
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The four great vessels of the neck: where they originate and terminate
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Originate from subclavian artery
Terminate circle of Willis (1) Right common carotid: originates from subclavian artery, bifurcates into external branch that supplies extracranial structures and an internal carotid artery (ICA) that irrigates brain. (2) Left common carotid: originates from ascending aorta, bifurcates (3) Left vertebral artery combines with the R vertebral artery and forms: basilar artery |
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R and L Posterior cerebral arteries: where the originate, what they supply
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Originate near intersection of posterior communicating artery & basilar artery.
Supply posterior cerebral regions |
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R and L Middle cerebral arteries: where the originate, what they supply
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originates from internal carotid
Supply lateral aspect of cerebrum, anterior temporal lobes & insular cortices. |
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R and L Anterior cerebral arteries: where the originate, what they supply
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arise from the internal carotid arteries
Supply the anterior regions of the cerebrum, medial frontal lobe & superior medial parietal |
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Anterior and Posterior Communicating arteries: what they connect
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(a) ACoA: joins two ACAs
(b) PCoA: connect the PCAs with the ICAs |
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Functions of CSF
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provide buoyancy that prevents brain from touching skull and regulate chemical environment of brain neurons
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Location and function of the Foramen of Monro
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opening in each lateral ventricle, how communicate with third ventricle
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Location and function of the Cerebral Aqueduct
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midbrain, connects fourth and third ventricle
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Location and function of the Cisterna Magna
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subarachnoid space where fourth ventricle empties
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CSF capacity and rate of production
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140 mL, 450 mL per day
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Hydrocephalus
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enlargement of ventricular system from an excess of CSF
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CN I
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olfactory, roof of nasal cavity through cribriform plate, terminates in olfactory bulb
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CN 2
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optic, optic disc, visual info to LG nucleus, sent to contralateral visual field
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CN 3
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Oculomotor, brainstem origin, movement of eye, pupillary light reflect
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CN 4
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trochlear, brain stem, depresses eye and rotates inward.
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CN 5
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trigeminal, motor and sensory, sensory nerve of face, three divisions: opthalamic, maxillary, and mandibular, join in the trigeminal ganglion outside brain stem and enter pons as a single nerve. Controls chewing muscles
a. Eyes (opthalamic): innervates orbit, nose, forehead, scalp b. Maxillary: innervates skin over cheek, upper portion of oral cavity c. Mandibular: innervates skin over jaw, area above ear, lower part of oral cavity |
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CN 6
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abducens, brain stem, contracts lateral rectus muscle, moves globe laterally
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CN 7
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facial, muscles of face, ear, neck, eyelids, and facial expression, taste from front of tongue, facial nucleus in pons & innervates ipsilateral muscles of face. Taste via chorda tympani to solitary tract in pons & medulla
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CN 8
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vestibular and cochlear division, balance and hearing, use mechanoreceptor in inner ear. Send info to pons. Vestibular goes to brain stem and cerebellum, cochlear goes to medial geniculate nucleus to primary auditory cortex
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CN 9
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glossopharyngeal, muscles of pharynx, tongue, nasopharynx, middle and outer ear, taste from back of tongue. Motor, sensory, and autonomic functions of face.
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CN 10
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vagus, parasympathetic input to thoracic and abdominal regions, larynx, pharynx, outer ear
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CN 11
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accessory, purely motor. Extension of spinal cord, neck and upper shoulders, helps us move our head. Lower medulla/ upper spinal cord
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CN 12
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hypoglossal, motor, move tongue, arises from medulla
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Three components of brain stem
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midbrain, pons, medulla
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The 10 cranial nerves that terminate in the brain stem that are tested in a neurological exam to localize pathology
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3-12
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Four major brain stem tracts
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Corticospinal tract
Corticobulbar tract Medial Lemniscus Spinothalamic tract |
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Corticospinal tract: location and function
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begins in precentral gyrus of frontal lobe, descends to the spinal cord, input to motor neurons that directly innervate voluntary muscles. Ventral portion of midbrain, pons, & medulla, decussates at medulla
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Corticobulbar tract: function
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similar origin/role as corticospial tract, terminates on various brain stem motor nuclei.
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Medial Lemniscus: location and function
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sensory, continuation of dorsal column system, information regarding vibratory and position sensation to contralateral ventral posterior lateral nucleus of thalamus & then to somatosensory cortex of parietal lobe
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Spinothalamic Tract: location and function
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sensory, transmits pain and temperature sensation from the periphery to contralateral VPL thalamic nucleus and then the parietal lobe
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Ascending Reticular Activating System (ARAS): function, consequences of damage, responsible for level of consciousness or content of consciousness?
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General activating system for brain, send fibers to thalamus, project to entire cerebrum. Major role in wakefulness and sleep, circadian rhythm. Damage results in loss of normal arousal and coma. LEVEL of consciousness.
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Cerebellum Functions
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coordination, postural control, equilibrium, and motor control
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Function of cerebellar hemispheres
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coordination of the limbs
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Function and location of Vermis
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postural adjustment
most medial portion of cerebellum |
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Cerebellar inputs
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vestibular, spinal, and cerebral cortical inputs through inferior and middle peduncles
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Cerebellar outputs
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sent from four deep nuclei through the superior peduncle to midbrain and then to contralateral ventral anterior and ventral lateral nuclei of thalamus, influence motor cortex
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Where ataxia can occur in cerebellar lesion
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ipsilateral side of body as the cerebellar lesion. Limbs, trunk, or speech
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Cerebellum's role in learning
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procedural learning (i.e. playing an instrument)
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Diencephalon: four parts
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thalamus, hypothalamus, subthalamus, and epithalamus
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Function of thalamus
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primarily sensation, also movement, arousal, cognition, and emotion. Sensory relay station.
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Function of Ventral Posterior Lateral (VPL) and Ventral Posterior Medial (VPM) nucs
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somatosensory info from contralateral side of body and face, taste
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Function of Lateral Geniculate Nuc (LGN)
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visual projections from optic nerve synapse
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Function of Medial Geniculate Nuc (MGN)
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auditory fibers synapse
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Inputs, outputs and function of Ventral Anterior Nuc (VA) and Ventrolateral Nuc (VL)
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fibers from cerebellum. Send fibers to basal ganglia. Motor function.
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Inputs, outputs and function of Intralaminar Nuc
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arousal system, receive input from brain stem ARAS and relay this input to activate the cerebrum.
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Inputs, outputs and function of Dorsal Medial (DM) and Pulvinar nucs
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association regions, contribute to cognition, connect with frontal and parietal-temporal-occiptal cortices.
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Connections and functions of Anterior nuc
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emotion, limbic system
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Hypothalamus: Overall Autonomic funcs
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maintain homeostasis, body temperature, digestion, circulation, water balance, sexual function
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Hypothalamus: Functions of Anterior regions
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parasympathetic branch
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Hypothalamus: Functions of Posterior regions
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sympathetic branch
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Hypothalamus means of managing endocrine function
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pituitary gland
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The response that makes the hypothal a key component of the limbic system
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fight or flight
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Subthalamus connections and their role
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connect to basal ganglia and cerebral cortex, function unknown
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Location of the Epithalamus
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superior and caudal to thalamus
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Function of the basal ganglia, gray matter or white matter
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Gray matter, modulation of the cerebral cortical control of voluntary movement.
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How basal ganglia differs from cerebellum in function.
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Cerebellum coordination, basal ganglia initiation and timing of movements.
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BG Input
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cortical, substantia nigra
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BG Output
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VA and VL thalamic nuclei
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BG Loop
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cortical inputs reach striatum by means of white matter tracts called internal/external capsules, go to globus pallidus, then to VA and VL thalamic nuceli. Return to motor cortex via internal capsule.
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Definition of Striatum
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caudate + putamen
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Lenticular nuc
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putamen + globus pallidus
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Location and function of Substantia Nigra and consequences of pathology
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midbrain, deliver dopamine to striatum, activate basal ganglia and motor system in general. Pathology = Parkinson’s (dopamine depletion), bradykinesia (slowness of movement), rigidity, resting tremor.
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Limbic system: origin of name
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limbus, meaning border
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Limbic connections
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thalamic, hypothalamic, and cortical
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Limbic components
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hippocampus, amygdala, cingulate gyrus, parahippocampal gyrus
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Limbic role in emotion (circuit)
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Papez circuit: cingulate gyrus, parahippocampal gyrus, the hippocampus, the fornix, mammillary bodies, mammillothalamic tract, anterior nucleus of the thalamus
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Amygdala location and function
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anterior temporal lobe
emotional learning and response, sensory input funneled through amygdala, assesses emotional valence |
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Hippocampus location
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medial temporal lobe
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Hippocampus components
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dentate gyrus, hippocampus proper, and subiculum
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Hippocampus structure
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curved sheet of three layered cortex
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hippocampus function
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acquisition of declarative memory (learning of facts and events)
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Consequences of damage to hippocampus
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severe and disabling dysfunction of recent declarative memory
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How we know DM nuc of thalamus or basal forebrain suggests all are involved in declarative learning
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if any is damaged, severe and disabling dysfunction of recent declarative memory
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White matter definition and function
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link cortical and gray matter regions, collections of CNS axons ensheathed with myelin, efficient communication in sensory and motor systems, integration of higher functions
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Categories of WM pathways
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afferent/efferent tracts, commissures, association tracts
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Afferent tracts (White Matter path)
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Sensory
thalamic tracts: relay somatosensory information from thalamus to parietal optic radiations: project from lateral geniculate body to the occipital cortex |
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Efferent tracts (WM path)
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Motor
Corticospinal tract: projects from motor cortex to lower motor neurons in spinal cord Corticobulbar tract: projects from motor cortex to motor neurons in brain stem |
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Function of the three Commissures
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Connect hemispheres
Corpus callosum, anterior commissure, hippocampal commissure |
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Function of association tracts (what regions or structures they link)
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join gray matter regions within each hemisphere
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Short association fibers (Arcuate or “U Fibers”)
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connect adjacent cortical gyri throughout cerebrum
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Long association fibers
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link ipsilateral cerebral lobes (superior occipitofrontal fasciculus and arcuate fasciculus, uncinate fasciculus, cingulum)
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Fornix
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arched tract in limbic system that connects hippocampus and mammillary bodies within Papez circuit
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Medial Forebrain Bundle
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joins hypothalamus with caudal and rostral brain regions, control of ANS
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Cerebral cortex
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outermost layer of cerebrum, thin sheet of neurons, most advanced functions of human brain, “bark”
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Neocortex
Proportion of cortex, number of layers and organization |
90%, 6 layers: outermost molecular layer, external granular cell layer, external pyramidal cell layer, internal granular cell layer, internal pyramidal cell layer, innermost multiform layer.
Vertical organization, columns of cells arranged perpendicular to the cortical surface, respond as a unit to a given stimulus |
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Allocortex: number of layers and where it's found.
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Olfactory system, hippocampus. Three layers: outer molecular layer, pyramidal cell layer, inner polymorphic layer
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Brodmann's areas: how many and how they are differentiated
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50, based on histological characteristics
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Frontal Lobe (location)
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most rostral, anterior to rolandic fissure, superior to sylvian fissure
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Temporal Lobe (location)
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inferior to the Sylvian fissure
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Parietal Lobe (location)
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posterior to rolandic fissure, inferior margin is defined by two lines that form the posterior extent of temporal lobe
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Occipital Lobe (location)
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posterior to both parietal and temporal lobes.
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Insula (location)
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under sylvian fissure
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Vertical organization of brain
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MacLean, triune brain, three levels of neural development
reptilian, paleomammalian, neomammalian |
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Reptilian brain
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brain stem, cerebellum. Thalamus
arousal, autonomic, cardiovascular, respiratory, and visceral functions |
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paleomammalian brain
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Limbic
drives, childrearing, communal bonding, territoriality |
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neomammalian brain
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Cerebral cortex
cognition & emotional behavior |
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Functions of the anterior cerebrum
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Motor
Primary motor, frontal operculum, medial frontal |
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Primary motor cortex
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frontal lobe, corticospinal & corticotubular tracts originate in precentral gyrus, cortical control of voluntary movement
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Frontal operculum
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motor aspects of language
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Medial frontal areas
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motivation to engage in voluntary action
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Functions of the posterior cerebrum
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Sensory
Temporal, parietal, occipital |
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Temporal lobes
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audition, comprehension of language and sounds
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Both Parietal lobes
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somatic sensation
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Right Parietal lobe
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visuospatial information
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Occipital lobe
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vision
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Function that is usually left hemisphere dominant
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language
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Functions that are usually right hemisphere dominant
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constructional ability, spatial attention, language prosody
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Nonlateralized functions
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higher functions, behavior, cognition
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Summary of Localizationists thought
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localization of function in nervous system, lesion method to study higher functions, map of brain-behavior relationships.
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Localizationists thought advantages and disadvantages
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Good for localizing cranial nerve deficits and hemiparesis, unreliable in identifying sites of higher functions, resembles phrenology
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Equipotential theory
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no specific localization of higher functions, all cerebral cortical areas are capable of supporting the operations of higher functions, lesion to any cortical zone could be expected to diminish neurobehavioral capacity in proportion to the amount of tissue damaged.
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Equipotential theory limitations
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Clinical and experimental evidence contradicts this claim, neuroimaging studies show specialization of cerebral areas exists
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network model
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Mesulam.
integrated ensembles of interconnected cerebral structures subserve specific neurobehavioral domains. Neuroanatomically linked networks that operate as a functional unit. |
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Frontal lobe size
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1/3 cortical surface
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Function Precentral gyrus (Brodmann 4)
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voluntary movement
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Function Broca's area (44 and 45)
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language fluency (left), motor prosody (right)
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Function Dorsolateral prefrontal (9 and 46)
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working memory
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Function Prefrontal (8, 9, 10, 46, 47)
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executive function
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Function Orbitofrontal (11, 12, 25)
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comportment (inhibit limbic impulses and maintain appropriate behavioral repertoire)
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Function Medial frontal / Cingulate gyrus (24, 32, 33)
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motivation
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Function Heschl's gyrus (41, 42)
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Temporal lobe
receive sound stimuli, primary auditory cortex |
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Left superior temporal gyrus aka Wernicke's area (posterior part of 22 on left)
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speech sounds are decoded, comprehension of language
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Right superior temporal gyrus (posterior part of 22 on right)
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emotional/expressive aspects of sound, interpretation of prosody, music
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Postcentral gyrus (3,1,2)
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Parietal
interpretation of tactile information |
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Angular gyrus (39) and supramarginal gyrus (40)
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Parietal
reading, calculation |
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Left parietal lobe in general
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Verbal
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Right parietal in general
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Nonverbal
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Network of locations in right parietal lobe and consequences of damage
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visuospatial function, negotiate 3D space, spatial attention. Damage = hemispatial neglect
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Calcarine cortex (17)
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Vision
Occipital |
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Areas next to calcarine cortex (18,19)
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Occipital
visual association cortex, perception of visual stimuli |
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Ventral occipital areas projecting into inferior temporal lobe
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what, recognition
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Dorsal occipital areas prjecting into parietal lobe
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where
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