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101 Cards in this Set

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  • Back
toward nose
toward tail
Spinal cord functions
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
Spinal cord location
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
Conus medullaris
where inferior end of spinal cord tapers
Filum terminale
long filament of CT extending from conus medullaris which attaches to coccyx inferiorly, anchoring spinal cord in place
Cauda equina
collection of spinal nerve roots in inferior end of vertebral canal
Cervical/lumbar enlargments
where spinal cord nerves for upper/lower limbs arise
Spinal nerves
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
Spinal cord segments
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
Spinal cord deep grooves
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)
White matter funiculi
divides white matter into dorsal, ventral, and lateral funiculi (long ropes)
Ascending white matter fibers
carry sensory info from sensory neurons to brain
Descending white matter fibers
carry motor info from brain to spinal cord to stimulate muscle contraction/gland secretion
Commissural white matter fibers
carry info from one side of spinal cord to the other
Commissure of white matter
bundle of axons that crosses from one side of CNS to the other
Gray commissure
cross-bar of H, unmyelinated axons with narrow central cavity
Dorsal horns of gray matter
posterior arms of H, run as columns the entire length of spinal cord, contain cell bodies of motor neurons and interneurons
Ventral horns of gray matter
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
Lateral horns of gray matter
small columns in thoracic/superior lumbar segments of spinal cord
Dorsal root ganglia of gray matter
sensory neuron cell bodies outside spinal cord
Dorsal roots of gray matter
where sensory neuron axons reach spinal cord
Dorsal horn interneurons of gray matter
receive info from sensory neurons
Somatic/visceral regions of gray matter
[dorsal] somatic sensory, visceral sensory, visceral autonomic motor, somatic motor [ventral]
loss of sensory function, damage to dorsal horn of sensory neuron cell bodies in dorsal root ganglia
damage to ventral horn or ventral motor roots destroys motor neurons
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
Epidural space of meninges
fat-rich cushioning space external to dura mater
Dura mater
strongest layer of meninges, single leathery layer of dense fibrous tissue, to level of S2
Subdural space
thin flui-filled space in between dira mater and arachnoid mater
Arachnoid mater
layer lies deep to dura mater, to level of S2
Subarachnoid space
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
Pia mater
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
Denticulate ligaments
lateral extensions of pia mater anchor spinal cord laterally to dura mater throughout length of cord
Cerebrospinal fluid
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
Lumbar puncture/spinal tap
needle is inserted b/w L4 and L5 vertebrae into subarachnoid space to obtain CSF or inject medicine
inflammation of meningeal tissues from infection
inflammation of brain or spinal cord from infection
1500 grams, performs complex neural functions (intelligence, memory, sensory-motor integration, etc), controls/maintains ANS and endocrine system
Embryonic development of brain, week 4
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)
Embryonic development of brain, week 5
primary brain vesicles develop into 5 secondary vesicles, prosencephalon divides into telencephalon and diencephalon, mesencephalon remains undivided, rhombencephalon divides into metencephalon and myelencephalon
cerebral hemispheres
thalamus, hypothalamus, epithalamus
pons and cerebellum
medulla oblongata
Organization of brain
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
Ventricles of brain
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)
Paired lateral ventricles
in cerebral hemispheres, horseshoe-shaped from bending of hemispheres, each has anterior/inferior horns, anterior horn separated by septum pellucidum
3rd ventricle
diencephalon, connected anteriorly with lateral ventricles by interventricular formena
cerebral aqueduct
midbrain, connects 3rd and 4th ventricles
4th ventricle
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
choroid plexus
lies in roof of 4th, 3rd, and lateral ventricles
brain stem
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
medulla oblongata
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
inferior cerebellar peduncles
fiber tracts connecting medulla and cerebellum
olive of medulle
contains inferior olivary nucleus
inferior olivary brain nucleus
large wavy fold of gray matter, relay station for sensory info travelling to cerebellum, especially for proprioceptive info ascending from spinal cord
pyramids of medulla
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
decussation of pyramids
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
CN 8, vestibulocochlear nerve
attaches at junction of medulla/pons in dorsolateral portion of medulla, sensory vestibular nuclear complex and sensory cochlear nuclei
CN 9, glossopharyngeal nerve
nucleus ambiguous (motor) and solitary nucleus (sensory)
CN 10, vagus nerve
dorsal motor nucleus of vagus, nucleus ambiguous, solitary nucleus
CN 11, accessory nerve
spinal accessory, branch of vagus nerve, associated brain nuclei located on rostral portion of spinal cord
CN 12, hypoglossal nerve
hypoglossal nucleus (motor)
Reticular formation
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
Visceral motor nuclei of reticular formation
cardiac center regulates force and rate of heart beat, vasomotor center regulates blood pressure, respiratory center regulates breathing, centers for hiccupping, sneezing, swallowing, coughing
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
Pontine nuclei
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
Middle cerebellar peduncles
carry info from cerebral cortex and pontine nuclei to cerebellum
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
Periaqueductal gray matter of midbrain
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
Corpora quadrigemina of midbrain
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
Substantia nigra of midbrain
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
Red nucleus of midbrain
deep to substantia nigra, reddish hue due to rich blood supply and presence of iron pigment in neuron cell bodies, associated with cerebellum
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
Cortex of cerebellum
outer gray matter which is neuron rich calculator that smoothes out body movements
Arbor vitae of cerebellum
internal white matter rich in axons which carry info to/from cortex
Depp cerebellar nuclei
deeply situated gray matter, gives rise to axons that relay instructions from cerebellar cortex to other parts of brain
Info on equilibrium in cerebellar cortex
relayed from receptors in inner ear through vestibular nuclei in medulla to flocculonodular lobe
Info on current limb/trunk movements in cerebellar cortex
from proprioceptors up spinal cord through olivary nuclei to medial portions of anterior/posterior lobes
Info from cerebral cortex
from cerebral cortex through pontine nuclei in pons to lateral portions of anterior/posterior lobes
Superior cerebellar peduncles
connect to midbrain and carry info away from cerebellum to cerebral cortex
Middle cerebellar peduncles
connect to pons and carry info into cerebellum from cerebral cortex through pontine nuclei
Inferior cerebellar peduncles
arise from medulla and carry fibers from vestibular nuclei and spinal cord through olivary nuclei into cerebellum
fibers to and from cerebellum
Coordinating movement by cerebellum
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
Higher cognitive functions of cerebellum
refines movements when learning new motor skill, motor memory, cognition of language, problem-solving, task planning
Injury to cerebellum
damage to anterior/posterior lobes = disorders in coordination, damage to flocculonodular lobe = disorders in equilibrium
forms center core of forebrain, surrounded by hemispheres, 3 structures (thalamus, hypothalamus, epithalamus), borders 3rd ventricle, composed of gray matter
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
Ventral posteriolateral nuclei of thalamus
relay station for sensory info ascending to primary sensory areas of cerebral cortex
Medial geniculate body of thalamus
receives auditory input
Lateral geniculate body of thalamus
receives visual input
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)
Feeding-initiating centers of hypothalamus
in lateral part
Feeding-inhibiting centers of hypothalamus
in ventromedial part
Suprachiasmatic nucleus of hypothalamus
biological clock, regulates timing of circadian rhythms in response to daylight-dark cycles
Preoptic nucleus of hypothalamus
responds to suprachiasmatic nucleus to induce sleep
Mammillary body of hypothalamus
receives inputs from hippocampal formation
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)