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101 Cards in this Set
- Front
- Back
Rostral
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toward nose
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Caudal
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toward tail
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Spinal cord functions
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spinal nerves attach to spinal cord, involved with sensory/motor innervation of body below head, provides 2-way conduction pathway for signals b/w body and brain, major center for reflexes
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Spinal cord location
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runs through vertebral canal of vertebral column through vertebral foramina, extends from foramen magnum at base of skull to L3 in infants and L1/2 in children in adults
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Conus medullaris
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where inferior end of spinal cord tapers
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Filum terminale
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long filament of CT extending from conus medullaris which attaches to coccyx inferiorly, anchoring spinal cord in place
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Cauda equina
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collection of spinal nerve roots in inferior end of vertebral canal
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Cervical/lumbar enlargments
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where spinal cord nerves for upper/lower limbs arise
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Spinal nerves
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31 pairs (PNS) attach to spinal cord through dorsal/ventral nerve roots, 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal, nerves lie in intervertebral foramina
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Spinal cord segments
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indicate the region of spinal cord where spinal nerve fibers emerge, located superior to there corresponding spinal nerves emerge (because spinal cord doesn’t extend to the end of spinal column), so segment T5 is located at level of T4
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Spinal cord deep grooves
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cord is wider laterally than anteroposteriorly, 2 grooves run length of cord and partly divide it into left/right halves (dorsal median sulcus, and ventral median fissure)
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White matter funiculi
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divides white matter into dorsal, ventral, and lateral funiculi (long ropes)
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Ascending white matter fibers
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carry sensory info from sensory neurons to brain
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Descending white matter fibers
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carry motor info from brain to spinal cord to stimulate muscle contraction/gland secretion
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Commissural white matter fibers
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carry info from one side of spinal cord to the other
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Commissure of white matter
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bundle of axons that crosses from one side of CNS to the other
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Gray commissure
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cross-bar of H, unmyelinated axons with narrow central cavity
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Dorsal horns of gray matter
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posterior arms of H, run as columns the entire length of spinal cord, contain cell bodies of motor neurons and interneurons
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Ventral horns of gray matter
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anterior arms of H, run as columns the entire length of spinal cord, contain cell bodies of motor neurons and interneurons, ventral are largest in cervical/lumbar segments, motor neurons send axons out of cord via ventral roots to supply muscles and glands
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Lateral horns of gray matter
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small columns in thoracic/superior lumbar segments of spinal cord
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Dorsal root ganglia of gray matter
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sensory neuron cell bodies outside spinal cord
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Dorsal roots of gray matter
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where sensory neuron axons reach spinal cord
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Dorsal horn interneurons of gray matter
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receive info from sensory neurons
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Somatic/visceral regions of gray matter
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[dorsal] somatic sensory, visceral sensory, visceral autonomic motor, somatic motor [ventral]
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Paresthesia
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loss of sensory function, damage to dorsal horn of sensory neuron cell bodies in dorsal root ganglia
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Paralysis
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damage to ventral horn or ventral motor roots destroys motor neurons
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Meninges
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3 CT membranes that lie external to brain/spinal cord, cover/protect CNS, enclose/protect blood vessels that supply CNS, contain cerebral spinal fluid, dura mater, arachnoide mater, pia mater
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Epidural space of meninges
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fat-rich cushioning space external to dura mater
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Dura mater
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strongest layer of meninges, single leathery layer of dense fibrous tissue, to level of S2
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Subdural space
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thin flui-filled space in between dira mater and arachnoid mater
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Arachnoid mater
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layer lies deep to dura mater, to level of S2
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Subarachnoid space
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filled with cerebral spinal fluid and large blood vessels that supply the neural tissue, spanned by web-like threads that anchor arachnoid mater to pia mater
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Pia mater
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innermost layer of meninges, clings tightly to spinal cord, delicate layer of CT richly vascularized with small blood vesels, extends to coccyx, has denticulate ligaments, clings to surface of brain and follows contours
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Denticulate ligaments
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lateral extensions of pia mater anchor spinal cord laterally to dura mater throughout length of cord
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Cerebrospinal fluid
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watery fluid that fills subarachnoid space and hollow cavities of brain/spinal cord, provides liquid cushion/buoyancy, nourishes, removes waste produced by neurons, carries chemical signals b/w parts of CNS
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Lumbar puncture/spinal tap
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needle is inserted b/w L4 and L5 vertebrae into subarachnoid space to obtain CSF or inject medicine
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Meningitis
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inflammation of meningeal tissues from infection
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Encephalitis
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inflammation of brain or spinal cord from infection
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Brain
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1500 grams, performs complex neural functions (intelligence, memory, sensory-motor integration, etc), controls/maintains ANS and endocrine system
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Embryonic development of brain, week 4
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brain arises from rostral part of neural tube, caudal portion of neural tube becomes the spinal cord, 3 primary brain vesicles emerge (prosencephalon, mesencephalon, rhombencephalon)
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Embryonic development of brain, week 5
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primary brain vesicles develop into 5 secondary vesicles, prosencephalon divides into telencephalon and diencephalon, mesencephalon remains undivided, rhombencephalon divides into metencephalon and myelencephalon
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Telencephalon
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cerebral hemispheres
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Diencephalon
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thalamus, hypothalamus, epithalamus
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Mesencephalon
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midbrain
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Metencephalon
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pons and cerebellum
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Myelencephalon
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medulla oblongata
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Organization of brain
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centrally located gray matter contains neuron cell bodies (brain nuclei) and interneurons that process info, external white matter has interneurons, cerebrum/cerebellum have additional gray matter called cortex which is external to white matter
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Ventricles of brain
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expansions of brain’s central cavity, filled with cerebrospinal fluid, lined with ependymal cells, continuous with each other and central canal of spinal cord: paired lateral ventricles (telencephalon), 3rd (diencephalon) and 4th (pons, cerebellum, medulla oblongata)
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Paired lateral ventricles
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in cerebral hemispheres, horseshoe-shaped from bending of hemispheres, each has anterior/inferior horns, anterior horn separated by septum pellucidum
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3rd ventricle
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diencephalon, connected anteriorly with lateral ventricles by interventricular formena
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cerebral aqueduct
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midbrain, connects 3rd and 4th ventricles
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4th ventricle
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in hindbrain brainstem, connects to central canal of inferior medulla and spinal cord, 3 openings in the walls (paired lateral apertures and median aperture), connect ventricles with subarachnoid space which allows cerebral spinal fluid to fill both ventricles
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choroid plexus
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lies in roof of 4th, 3rd, and lateral ventricles
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brain stem
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midbrain, pons, medulla oblongata, each 1 inch long, make up 2.5% mass, function = passageway for all fiber tracts running b/w cerebrum and spinal cord, innervation of face/head, 10 pairs of cranial nerves associated, generates autonomic behaviors necessary for survival
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medulla oblongata
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conical shaped, continuous with spinal cord at level of foramen magnum of skull, most caudal level of brain stem, part of 4th ventricle lies dorsal to rostral half of medulla, cranial nerves 8-12 attach to medulla (lie near 4th ventricle), CN 6 and 7 emerge from brainste, b/w medulla and pons
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inferior cerebellar peduncles
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fiber tracts connecting medulla and cerebellum
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olive of medulle
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contains inferior olivary nucleus
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inferior olivary brain nucleus
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large wavy fold of gray matter, relay station for sensory info travelling to cerebellum, especially for proprioceptive info ascending from spinal cord
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pyramids of medulla
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2 longitudinal ridges with lie on ventral surface, formed by pyramidal tracts that extend through brainstem and spinal cord carrying voluntary motor output from cerebrum to spinal cord
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decussation of pyramids
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in caudal part, most of pyramid fibers cross over to opposite side of brain to enable each hemisphere to control voluntary movements of opposite side of body
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CN 8, vestibulocochlear nerve
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attaches at junction of medulla/pons in dorsolateral portion of medulla, sensory vestibular nuclear complex and sensory cochlear nuclei
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CN 9, glossopharyngeal nerve
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nucleus ambiguous (motor) and solitary nucleus (sensory)
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CN 10, vagus nerve
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dorsal motor nucleus of vagus, nucleus ambiguous, solitary nucleus
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CN 11, accessory nerve
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spinal accessory, branch of vagus nerve, associated brain nuclei located on rostral portion of spinal cord
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CN 12, hypoglossal nerve
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hypoglossal nucleus (motor)
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Reticular formation
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loose cluster of brain nuclei that run through core of brainstem, stimulate cerebral alertness and regulates muscles, present in medulla, forms 3 columns that extend length of brainstem (midline raphe nuclei, medial nuclear group, lateral nuclear group), contain pontine nuclei in motor tracks
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Visceral motor nuclei of reticular formation
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cardiac center regulates force and rate of heart beat, vasomotor center regulates blood pressure, respiratory center regulates breathing, centers for hiccupping, sneezing, swallowing, coughing
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Pons
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bulge in brainstem, forms ventral bridge b/w brainstem and cerebellum, separated from cerebellum by 4th ventricle, contains nuclei of cranial nerves 5-7 (trigeminal nerve, abducens nerve, facial nerve), function = receive sensory impulses and initiate motor activity to structures of head, reticular formation, pontine nuclei, pyramidal motor tract, middle cerebellar peduncles
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Pontine nuclei
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relay brain nuclei in a path that connects a portion of cerebral cortex with cerebellum which contributes to coordination of voluntary movements, send axons to cerebellum in thick middle cerebellar peduncles
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Middle cerebellar peduncles
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carry info from cerebral cortex and pontine nuclei to cerebellum
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Midbrain
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b/w pons and diencephalon, central cavity = cerebral aqueduct, ventral surface = cerebral peduncles with pyramidal tracts (ventricle part of peduncle = crus cerebri), pair of superior cerebellar peduncles connect midbrain to cerebellum
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Periaqueductal gray matter of midbrain
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surrounds cerebral aqueduct, involved in sympathetic response, mediates visceral pain, most ventral part contains motor neuron cell bodies to CN 3 (oculomotor) nuclei and CN 4 (trochlear) nuclei (only CN that emerges from dorsal brainstem
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Corpora quadrigemina of midbrain
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largest brain nuclei in midbrain, make up tectum (roof) of dorsal midbrain and form 4 bumps on dorsal surface, divided into 2 superior (visual reflexes) and 2 inferior (reflexive response to sound) colliculi
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Substantia nigra of midbrain
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embedded in midbrain white matter, contain neuronal cell bodies with melanin, deep to pyramidal tracts of cerebral peduncle, functionally linked to basal nuclei and deep gray matter of cerebrum, degeneration of neurons contribute to parkinson’s
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Red nucleus of midbrain
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deep to substantia nigra, reddish hue due to rich blood supply and presence of iron pigment in neuron cell bodies, associated with cerebellum
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Cerebellum
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located dorsal to pons/medulla (separated by 4th ventricle), 11% mass, smoothes/coordinates body movements directed by other brain regions, helps maintain posture/equilibrium, 2 hemispheres connected by vermis, folded into ridges (folia) separated by grooves (fissures), each hemisphere subdivided into anterior/posterior/flocculonodular lobes
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Cortex of cerebellum
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outer gray matter which is neuron rich calculator that smoothes out body movements
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Arbor vitae of cerebellum
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internal white matter rich in axons which carry info to/from cortex
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Depp cerebellar nuclei
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deeply situated gray matter, gives rise to axons that relay instructions from cerebellar cortex to other parts of brain
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Info on equilibrium in cerebellar cortex
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relayed from receptors in inner ear through vestibular nuclei in medulla to flocculonodular lobe
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Info on current limb/trunk movements in cerebellar cortex
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from proprioceptors up spinal cord through olivary nuclei to medial portions of anterior/posterior lobes
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Info from cerebral cortex
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from cerebral cortex through pontine nuclei in pons to lateral portions of anterior/posterior lobes
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Superior cerebellar peduncles
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connect to midbrain and carry info away from cerebellum to cerebral cortex
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Middle cerebellar peduncles
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connect to pons and carry info into cerebellum from cerebral cortex through pontine nuclei
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Inferior cerebellar peduncles
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arise from medulla and carry fibers from vestibular nuclei and spinal cord through olivary nuclei into cerebellum
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Ipsilateral
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fibers to and from cerebellum
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Coordinating movement by cerebellum
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1) cerebellum receives info on movement from motor cortex, 2) cerebellum compares intended movement with body position, 3) cerebellum sends instructions back to cerebral cortex to continuously coordinate, adjust/fine tune motor commands to spinal cord
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Higher cognitive functions of cerebellum
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refines movements when learning new motor skill, motor memory, cognition of language, problem-solving, task planning
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Injury to cerebellum
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damage to anterior/posterior lobes = disorders in coordination, damage to flocculonodular lobe = disorders in equilibrium
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Diencephalon
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forms center core of forebrain, surrounded by hemispheres, 3 structures (thalamus, hypothalamus, epithalamus), borders 3rd ventricle, composed of gray matter
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Thalamus
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inner room, 80% of diencephalon, 12 major brain nuclei, relay station for incoming sensory info, gateway to cerebral cortex, afferent impulses from all conscious senses except olfaction converge here, nuclei organize/amplify or scale down signals
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Ventral posteriolateral nuclei of thalamus
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relay station for sensory info ascending to primary sensory areas of cerebral cortex
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Medial geniculate body of thalamus
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receives auditory input
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Lateral geniculate body of thalamus
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receives visual input
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Hypothalamus
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below thalamus, b/w optic chiasm and border of mammilary bodies, pituitary gland projects inferiorly from hypothalamus, 12 brain nuclei, main visceral control center of body, regulates sleep-wake cycles, some nuclei near mammillary body mediate arousal from sleep, functions = control of ANS, endocrine system, body temp, hunger/thirst (sense concentrations of nutrients/salts in blood), emotional responses, motivational behavior, memory (mammillary body)
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Feeding-initiating centers of hypothalamus
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in lateral part
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Feeding-inhibiting centers of hypothalamus
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in ventromedial part
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Suprachiasmatic nucleus of hypothalamus
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biological clock, regulates timing of circadian rhythms in response to daylight-dark cycles
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Preoptic nucleus of hypothalamus
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responds to suprachiasmatic nucleus to induce sleep
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Mammillary body of hypothalamus
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receives inputs from hippocampal formation
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Epithalamus
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dorsal part of diencephalon, roof of 3rd ventricle, one tiny group of brain nuclei, contains pineal gland (secretes melatonin, contributes to control of circadian rhythms)
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