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comd-322
neuroanatomy
| Question | Answer |
|---|---|
| Gyrus | an elevation or ridge on the surface of the cerebrum |
| Sulcus (or fissure) | groove on the surface of the brain or spinal cord |
| Opercular | margins of the cerebrak convulusions serving as a cover |
| Commisure | a band of fibers that connect part of the brain or spinal cord with the same structures on the opposite side |
| Gray Matter | part of the brain that consists of nerve cells, glia cells, and unmyelenated fibers |
| White Matter | myelenated nerve fibers that form tracts and carry information from one brain site to another |
| Stria | bands of fibers that may differ in color or texture |
| Colliculus | a small prominence of nervous tissues "little hills" |
| Tract/fasciculus | a collection of nerve fibers all having a common origin in the CNS |
| Brachium | another name for a bundle of connecting pathways-used for pathways connecting the cerebellum to the brainstem |
| Bundle | a group of fibers: a fasciculus |
| Column | a pillar of fibers |
| Fasciculus | a small bundle |
| Funiculus | a cord of nerve fibers in a nerve trunk |
| Lemniscus | a ribbon of fibers |
| nucleus | a well defined collection of nerve cells in the CNS |
| Ganglion | a well defined collection of nreve cells in thr PNS |
| Decussation | crossing of incoming or outgoing fibers at midline i.e. Decussation of the pyramids in the medulla |
| Motor (efferent) | -Carry neural instructions from the brain to the muscles or glands-travel from the CNS to the periphery via efferent pathways-a few hundred thousand (relatively small amount) |
| Sensory (afferent) | -consuct nerve impulses froma sensory receptor-deliver sensory information to the brain and spinal cord for processing-travel from the periphery to the more central structures via afferent pathways-Approx. 5 million sensory neurons |
| Organizational Principles of the Brain | 1.-Interconnectivity in the brain2.-Centrality of thr CNS3.-Hierarchy of neuraxial organization4. Laterality of Brain organization |
| 1. Interconnectivity in the brain | -the brain is full of integrative networks where there is communication between hemispheres and within hemispheres-messages from multiple sources are bale to be integrated rapidly for appropriate responses to stimuli. |
| 2. Centrality of the CNS | -CNS integrates all incoming and outgoing information-CNS generates appropriate responses to information received-responses can be volitional or reflective. |
| 3. Hierarchy of Neuraxial Organization | -The CNS is hierarchically developed in compexity and organization of functions -lower segments (e.g. spinal cord) process basic reflexes -As complexity of processing increases, level of processing becomes more cephalic |
| Laterality of Brain organization | 1.bilateral anatomical symmetry-2 cerebral hemispheres similar in look, different in function2. Unilateral functional differences-after a few years of life, people develop hemisphere specialization3. contralateral sensorimotor control-all sensory and |
| Plasticity in the brain | -the brain is somewhat able to adapt to pathologies - the younger the person the higher liklihood of cellular rearrangement- nerves can regenerate to verying degrees in the PNS and CNS |
| Rostral | toward the head |
| Caudal | toward the tail |
| dorsal | toward the backbone |
| ventral | away from the backbone |
| proximal | toward the body or root of extremity |
| distal | away from the body or root of extremety |
| sagittal | right from left |
| coronal | front from back |
| tranverse vs cross | upper from lower |
| lateral | away from midline |
| medial | toward axis or midline |
| inter | between |
| intra | within |
| ipsi | same |
| contra | opposite |
| Central Nervous System | consists of Brain and Spinal cord |
| Brain | concerned with "higher" centers of control |
| Spinal cord | contains "lower" centers and is concerned with reflex control-provides a pathway between the brain and the peripheral nerves of the trunk and limbs |
| Brain division | -Forebrain-Midbrain-Hindbrain |
| Forebrain | -Telencephalon-cerebral hemispheres, basal nuclei-Diencephalon-Thalamus, Hypothalamus |
| Midbrain | -Mesencephalon |
| Hindbrain | -Metencephalon-pons-myelencephalon-medulla |
| Telencephalon | brain weighs about 3 lbs and the integrated combined activities of the cerebral hemispheres and diencephalon provide:language, attention, memory, temporospatial orientation, judgement, and reflective thinking |
| Cerebral Hemispheres | R and L halves largest part of the brain by volume, weight and surface area-contains deeply wrinkled surface to accomodate a higher surface area (gyri)-Higher function as in cognition, language and memory-regulates sensorimotor, prcptn/exper relation- |
| Cerebrum | Cerebral Cortex-thin layer that envelopes hemispheres, 6 layers on neurons, part of brains gray matter, high concentration of neuronal cell bodies, presence of interneuronsWhite Matter-tissue underlying cortex, presence of interneuron axons |
| Cellular Organization (Cytoarchitechture) | Layer I-molecularLayer II-external granularLayer III-external PyramidalLayer IV-internal granularLayer V-Internal pyramidalLayer VI-multiform |
| Cerebrum Fissures | the deep valleys formed by the gyriMain Fissures or Sulci- Longitudinal (seperates hemispheres), Central Sulcus ( seperates anterior and posterior, ends at the lateral fissure...2cm deepseperates primary Motor from Primary Sensory cortex |
| Cerebrum Fissures | Lateral Fissure(Sylvian)- courses along side of cerebellum, seperates front and temporal lobes anteriorly, extends partially between the paraetal and temporal lobes posteriorlyParieto-Occipital sulcus-seperates Parietal lobe from Occipital |
| Cerebrum | Major Subdivisions-Frontal LobeParietal LobeTemporal LobeOccipital LobeLimbic Lobe (?)Insular Lobe (?) |
| Cortex can be divided into: | Primary Motor Projection areas (precentral gyri area of the frontal lobe-Primary Sensory reception areas (primary auditory cortex, primary sensorimotor cortex, primary visual cortex-Association areas 86% of cortex and include motor and sensorimotor Ass. |
| Association Areas | -Unimodal -Polymodal-Supramodal |
| Unimodal Association area | only 1 type of info is processedareas elaborate on info recieved at adjacent primary motor and sensory areas |
| Polymodal Association area | found near unimodal areas, near the primary reception cortex-processes 2 or more kinds of sensory info-matches present sensory info with past sensory info |
| Supramodal Association area | Highest level of processing-concerned with neural process not linked directly with sensory or motor functions |
| Frontal Lobe | -largest lobe-considered CEO-occupies 1/3 of the hemisphere-contains 4 important gyri (precentral, superior frontal, middle frontal, inferior frontal gyrus |
| Precentral Gyrus=Primary Motor Cortex | Precentral sulcus=anterior boundaryMotor Strip/motor cortex/primary motor cortex (lies anterior to the centrak fissure, cortical region in which the body movements are represented, stimulation will move the corresponding Body part on opposite side |
| Premotor area-rostral to the precentral sulcus | This area has been shown to be activated in the following tasks: motor tasks that require internal generation of movement (speech)performance of repetative, sequential motor tasksPLanning of learned movement,verbal and nonverbal naming tasks |
| Prefrontal Cortex | remaining anterior portion of the frontal lobecontributes to cognitive functions:reasoning, abstract thinking, planning, self-monitoring, decision making, planning, pragmatic behavior, intellect TBI patients thus present impulsive, uninhibited etc |
| Broca's area-Anterior language cortex | made up of the opercular and triangular portions of the inferior frontal gyrus-important area of spokane language-in front of the area of the 1st motor cortex that controls jaw, lip, tongue and vocal cord movements |
| Parietal Lobe | between frontal and occipital lobes and above temporal lobesRoles: Perception of somatic sensation, perceptual synthesis, spatial orientation, cross-modality-integration, memory, cognition, interpretation and elebaoration of sensory exp. Pri Sens Crtx |
| Sensory Strip primary sensory cortex, somatasensory cortex | contains sensory representation of the bodythe amount of cortex allocated reflects how sophisticated the motor control or sensory info is |
| Parietal Sensory associtaion cortex | sensation from the primary sensory cortex are elaborated to awareness |
| Parietal lobe pathology | Lesions to the P.L. can result in:contralateral sensory losscomplex perceptual disorders of constructional skillsspatial oriention deficitsbody schema deficitesmemory deficitinattention to and neglect of the contralateral half of the body |
| Supramarginal Gyrus | fold of cortex that curves around the end of the lateral fissureresponds to acoustic stimulationinvolved in language proccessingmay be involved in phonological storagelesion effects-agraphia (writing disorders) |
| Angular Gyrus | posterior to the supramarginal gyrusdamage can result in dyslexia |
| Occiptial Lobe | a small prtion of this lobe is on the lateral surface but is more fully developed along the medial surface of the hemispherecontains:primary visual cortex, secondary visual cortex |
| Temporal Lobe | contain 3 prominent gyrisuperior temporal gyrimiddle temproal gyriinferior temporal gyri |
| Primary auditory cortex/Heschl's gyrus/transverse gyrus | located in the lateral fissure2/3 posterior on the upper surface of the temoral lobecontains 2-3 gyri depending on the individualPrimary processor of auditory signals |
| Language Assocition area/ Wernickes's area | Superior part of the temporal lobeinvolved in analysis and elaboration of speech sounds and verbal memory in dominant (typically left) hemisphereperception of nonverbal auditory information in the non dominant hemisphere (typically right) |
| Wernicke's Area | center for language comprehensionpossible storage of sounds or the phonological representation of wordsdamage can result in poor receptive language skills, fluent but nonsensical speechword finding difficulties(anomia) |
| Connection Fibers: Fasciculi | 2 primary types-Association adn commisuralAssociation-connect 2 cortical areas within one hemisphere-Superior Longitudinal fasciculus-Inferior Longitudinal fasciculus-Arcuate fasciculus-Cingulus-uncinate fasciculus |
| Commissural Fibers | 4 bundles of fibers that connect the two hemispheres:corpus callosumanterior commissuremiddle commissureposterior commissureProjection fibers-connect the cerebral cortex to the lower areas of the CNS |
| Limbic System | Limbic=bordera ring of cortex on the medial aspect of the cerebral hemispheresphylogenetically, the limbic system is among the oldest parts of the braincomposed of fewer than 6 layers, instinct and emotionthink...going postal |
| Limbic system Structures | -limbic lobe-hippocampus (seahorse)-Amygdala (almond)-Septal area (partition deviding wall)-mammillary bodies (breast like)-anterior nuclues of the thalamus |
| Amygdala (amygdaloid nucleus) | -nuclear complex situated immediately rostral to the hippocampus*receives direct olfactory information-reciprocally connected with hypothalamus-prjects to thalamus and neocortex-has role in control of emotions, sex. behavior, food/water intake, |
| Septal area | cell mass located aterior to hypothalaumshas two-way connections with hypothalamus and hippocampusinvolved in control of:emotions, motivational functions, viscoral and endocrine functions, sensorimotor functions, reproduction functions |
| General functions of the Limbic System | -concerned with emotional behavior, especially fear and anger-the hyppocampal formation is concerned with recent memory and learningIt is the complexity of behavioral responses that result in the complexity of the limbic system |
| Lesion Effects in the Limbic System | Many interconnections makes it difficult to attribute effects to lesions of particular parts of the limbic system, but some lesion effects are well-describes:Bilateral hippocampal lesion-recent memory deficit (50 first dates) |
| Kluver-Bucy Syndrome | -due to bilateral damage to the hippocampus, amygdala and inferior temporal cortex-results in recent memory deficit-visual agnosia (can see but can't make sense out of what is seen)behavior disturbance-hypersexuality, hyperphagia, placcidity |
| Korsakoff's Syndrome | -linked with alcohol abuse-caused by thiamin (vitamin B) deficiency-destruction of mammilary bodies which are involved in memory processes, recent memory deficit |
| Seizures | seizures from the amygdala and surrounding temporal lobe structures can result in:automatic aggressive behaviors,memory impairment, impaired ablility to monitor behavior and face the consequences |
| Contents of the Diencephalon | 1.Thalamus-80% of diencephalon2.Hypothalamus3. Subthalamus4. Epithalamus |
| Thalamus | a complicated collection of gray matter that acts as a relay station for many interconnectionsOvid shape,situated on either side of 3rd ventricalVast amount of sensory info converges here and is integrated throught the interconn. of nuclei |
| Thalamus cont. | Sensory relay stationThalmuc structure divided into 3 teirs of nuclei:mediodorsalLateralVentral |
| Thalamic Nuclei | have different afferent and efferent connection-some have sensory input for general and special senses;then project to the corrseponding sensory area of cortex (except olfction) |
| Other thalamic nuclei | partcipate in emotional aspects of brain function-are functionally related to motor and association areas of cortex-have a role int eh ascending reticular activating system (what keeps you alert) |
| Functional Classification of thalamic nuclei | Specific*primary sensory-receives information for vision;tonotopic info to primary auditory cortex;and sensation of pain, temp., discriminative touch to the somatosensory cortex*Secondary sensory*Association sensory |
| Nonspecific thalamic nuclei | receive general and diffuse info from cortical areas, basal ganglia, and reticular information and project diffusely to these areas, as well as specific thalamic nuclei |
| Hypothalamus | small, old and very importantconsists of a number of nuclei which are situated in the flow and lower lateral walls of the 3rd ventrical-many regulatory functions, but he functions are modified by information received alonf numerous afferents pathways |
| Hypothalamus cont. | Especially infor from limbic sys. and prefrontal cortexexerts its influence on bodily functions through the autonomic nervouse system and endocrine system*It's the cheif center of the brain for mnt.and regulate bodily func. temp/sleep/eat/drink |
| Temperature regulation by hypothalamus | anterior hypothalamic areakeeps body temp to a normal levels by vasodilation and sweatingPosterior area subserves heat consumption and production like shivering adn vasoconstriction |
| Food and water intake regulation by hypothalamus | satiety center- ventromedial nucleusfeeding center-lateral regionthirst-other parts of lateral region |
| Sexual behavior regulation by hypothalamus | -anterior hypothalamus associated with sexual behavior-vast interconnections with limbic system make it difficult to attribute these behaviors w/hypothalamus |
| Sleep/Wakefulness reg. by hypothalamus | anterior hypothalamus may be the sleep centerposterior may be the waking center |
| Subthalamus | included in the diencephelaon but more functionally related to basal ganglia (movement)-refers to nuclei b/w the thalamus and the mid-brain-includes the subthalamic nucleus-deep brain stim targets this to treat PD-contralateral hemiballism |
| Epithalamus (around the thalamus) | consists of-Habenualr nucleus which is part of a circuit that serves autonomic functions such as amotional drive and possibly the sense of smell-pineal gland- gonadal and diurnal rythyms-stria medularis- |
| Basal Ganglia (nerve knots) | The term is used to describe a number of subcortical nuclear structures which are telencephalic in origin adn participate in control of movement-primary input from cortex-output-through thalamus back to prefrntl, premotor and motor cortex |
| Basal Ganglia | important in controlling motor functions of the body-cognitive motor learning-influences initiation of movement-influences how much movement-PDcan be Hypo or Hyperkinetic dysarthria |
| Basal Ganglia structures | -Corpus Striatum-Substantia nigra-Subthalamic nuclei |
| Corpus Striatum | Caudate nucleus-shpaed like a shrimp with a large head and curving tail-lenticular formation (or lentifrom nucleus) -pentamen stone and globus plalidus globe, nestled together collectivlely termed as the striatum |
| Substantia Nigra | located in the midbrain but functionally part of the Basal GangliaConsists of:Pars compacta and Pars reticulata |
| Circuitry of the Basal Ganglia | -Two major pathways: inderect and directcortical inouts to the neostriatum are excitatory and are mediated by glutamate-excitatory and inhibitory pathways |
| Connections in the BG circuitry | -reciprical connections between the substantia nigra and the striatum-reciprocal connections between globulus pallidus and subthalamic nucleus-pathway from intralaminar nuclei (thalamus) through striatum and globus pallidus |
| Basal Ganglia Control Circuit | -first part of the control circuit descends from the cortex-these fibers transmit info about planned upcoming movements to the BG-The BG smooth and refine these planned movements-refined movements to motor cortex-UMN-pyramidial-LMN |
| Lesions of the basal ganglia | reduces movement or fails to inhibit involuntary movement-2 major classes of syndrome linked to BG lesions: Hyperactive/Hyperkinetic e.g. Huntington's-Hypoactive/Hypokinetic e.g Pakinsonism |
| Cerebellum | "little brain"-inferior to the cerebrum and posterior to the brainstem-consists of two hemispheres |
| Cerebellum | -controls smooth constraction of voluntary muscles-coordinates that contraction together with relaxation of muscle antagonists-processes sensory info from all over the body and integrates that info into execution of a movement-40 fibers in for 1 out |
| General Cerebral function | -maintain equilibrium-coordinate muscle action in both:stereotyped movement (gait)non-stereotyped (reaching for something) |
| Basic Anatomy of the Cerebellum | 3 main lobes:anterior=paleocerebellummiddle lobe=neocerebellumFlocculonodular lobe=archeceribellumInterior is made up of both gray and white matter-gray outside, white inside |
| Lesion effects in cerebellum | broad based gaitpostural changesnystagmus-involuntary cyclical mvmnt of eyeballintention tremors-occurs when trying to reach something-motor learning-dysdiadochokiness-diff. with rapid alternating movementdistrbnc of reflexesataxicdysarthria |
| Brainstem | attaches diencephalon with spinal cordincludes midbrain, pons and medullaintegrates and coordinates centrally and peripherally acquired infocontains automatic control systems vs. cortex |
| Brainstem | essential life functions:regulation of body temp, respiration, swallowing, digestion |
| Brainstem lesions | can result in:inpaired ocular controlaltered consciousnesssensorimotor deficit on the contrlateral half of the body |
| Brainstem | all three portions contain ascending and decending fiber tractscranial nerves and nuclei are located at various places in the midbrain pons and medulla |
| Brainstem | cerebellum is attached to the brainstem posteriorlyCerebellar peduncles are bundles of tracks that attach the brainstem to the cerebellum |
| Internal Anatomy of the brainstem | Has 3 logitudinal divisions:Tectum-mediates visual reflexesTegmentum-central part of midbrainBasis pedunculi-ventral to tagmentum (consists of substantia nigra, pes pedunculi which are pyrimidial fiber tracts |
| Midbrain | Lateral and Dorsal surfaces-inferior and superior colliculi |
| Interior colliculi | relay center for the transmission of auditory impulses from ear to thalamus and auditory cortexmediates reflexes triggered by auditory stimuli |
| Superior colliculi | reflex control of eye movements, visual reflexes, coordinates vestibular-generated head and eye movements |
| Cranial nerves | III oculomotorIV trochlear |
| Pons | gets its name because of bulging on ventral surface;bridges connecting the R and L cerebral hemispheresrelay station from a hemisphere of cortex to the opposite cerebellar hemisphere |
| Medulla | between pons and spinal cordsuperior border is the pontine protrusioninferior border is at the first cervical nreve rootlets and the crossing of the corticospinal fibers (pyramidial decussion)shaped like upside down conetransmission pathways |
| Medulla cont. | Certain landmarks-ventral median sulcus: on each side of this is the pyramid where the corticospinal fibers come throughthe pyramids tper inferiorly and its here that the corticospinal fibers decussateOlives-inferioir olivary nucleus |
| Spinal Cord | the medulla gives way to the spinal cord as it goes through the magnum foramen at base of skull5 regions:CervicalThoracicLumbarSacralCoccygeal |
| Cross section of Spinal Cord | Sensory nerves are dorsalMotor nerves are ventral |
| Peripheral Nervous System | 12 cranial nerves-sensory, motor, both31 pairs of spinal nerves-sensory, motorAutonomic and Somatic Division |
| Autonomic Nervous System | 2 structural and functional components:Sympathetic Nervous System and Parasympathetic Nervous System |
| Sympathetic Nervous System | INvolved in fight or flight or "fright and fight" reactions-mobilizes energy for emergencies*increased heart rate*dilation of pupils*increased sweating*elevation of bloos pressure*decrease in activity of digestive organs |
| Parasympathetic Nervous System | antagonistic to the Sympathetic NS-conserves energy and restores balance of visceral function so *heart beats slower*pupils constrict*blood pressure reduces*activity of the stomach and intestines (take it easy after a meal) |
| Somatic | Nerves carry voluntary info to and from the muscles, joints and skin |
Created by:
bethhsmith
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