Anatomy_Key Terms_Ch13 Flashcards
rostrally
”"”toward the snout””, (unique to the CNS), higher or more anterior regions of the brain”
caudally
”"”toward the tail””, (unique to CNS), inferior or more posterior parts of the CNS”
brain stem
consists of the midbrain, pons, and medulla
ventricles
”"”little bellies””, central cavity of the neural tube enlarges in certain regions to form the hollow _”
lateral ventricles
“(once called the first and second ventricles), lie in the cerebral hemispheres. anteriorly, the two lateral ventricles lie close together, separated by only a thin median membrane called the septum pellucidum (““transparent wall””)”
third ventricle
lies in the diencephalon. anteriorly, it connects to each lateral ventricle through an interventricular foramen
cerebral aqueduct
thin tubelike central cavity in the midbrain which connects the third and fourth ventricles
fourth ventricle
lies in the brain stem, dorsal to the pons and the superior half of the medulla oblongata. three openings occur in the walls: the paired lateral apertures and the median aperture in its roof. these holes connect the ventricles with the subarachnoid space, which surrounds the whole CNS. this connection allows cerebrospinal fluid to fill both the ventricles and the subarachnoid space. the _ connects caudally to the central canal of the inferior medulla and spinal cord
brain nuclei
gray matter in the form of clusters of neuron cell bodies
fiber tracts or tracts
pathways in the white matter in the brain allowing for interconnection and rapid processing between areas of the CNS
pyramids
two longitudinal ridges that flank the ventral midline of the medulla
decussation of the pyramids
”"”a crossing””, in the caudal part of the medulla, 70-90% of the pyramidal fibers cross over to the opposite side of the brain, resulting in each cerebral hemipshere controlling the voluntary movements of the opposite side of the body”
olive
enlargement just lateral to each pyramid
inferior olivary nucleus
a large wavy fold of gray matter veiwable in cross section, a relay station for sensory information traveling to the cerebellum, especially for proprioceptive information ascending from the spinal cord
relay nuclei
(such as the inferior olivary nucleus) process and edit information before sending it along
inferior cerebellar peduncles
fiber tracts that connect the medulla to the cerebellum dorsally
nucleus gracilis and nucleus cuneatus
ascending fibers carrying general sensation from the discriminative sense (touch, pressure, limb/joint position) from the skin and proprioceptors synapse in these medullary nuclei along their pathway to the cerebrum
reticular formation
loose cluster of brain nuclei running through the core of the brain stem
pontine nuclei
relay brain nuclei in a path that connects a portion of the cerebral cortex with the cerebellum (via pons)
middle cerebellar peduncles
pontine nuclei send axons to the cerebellum in the thick _
tectum
”"”roof””, central cavity of the midbrain is the cerebral aqueduct, which divides the midbrain into a _ dorsally and paired cerebral peduncles ventrally”
cerebral peduncles
o nthe ventral surface of the brain form vertical pillars, contain the pyramidal motor tracts descending from the cerebrum toward the spinal cord
crus cerebri
”(““leg of the cerebrum””), ventral part of each cerebral peduncle that contains the pyramidal motor tracts”
superior cerebellar peduncles
located dorsally, contain fiber tracts that connect the midbrain to the cerebellum
substantia nigra
deep to the pyramidal tracts in the cerebral peduncle, functionally linked to the deep gray matter of the cerebrum, the basal nuclei, and is involved in controlling voluntary movement
red nucleus
lies deep to the substantia nigra, minor motor function: helping to bring about flexion movements of the limbs; closely associated with the cerebellum
periaqueductal gray matter
gray matter surrounding the cerebral aqueduct and containing the oculomoter (cranial nerve III) and the trochelear (cranial nerve IV) nuclei
corpora quadrigemina
”"”quadruplets””, brain nuclei which make up the tectum and integrate the auditory and visual reflexes”
superior colliculi
”"”little hills””, act in visual reflexes, form bumps on the dorsal surface of the midbrain”
inferior colliculi
act in reflexive responses to sounds, form bumps on the dorsal surface of the midbrain
vermis
medially connects the two expanded cerebellar hemispheres
folia
the surface of the cerebellum is folded into many platelike ridges called _
fissures
deep grooves that separate the folia
arbor vitae
internal white matter (middle of three regions of the cerebellum)
deep cerebellar nuclei
deeply situated gray matter (deep of three regions of the cerebellum)
thalamus
”(““inner room””), paired structure that makes up 80% of the diencephalon and forms the superolateral walls of the third ventricle”
interthalamic adhesion
(intermediate mass), small midline connection that usually joins the right and left parts of the thalamus
hypothalamus
”"”below the thalamus””, inferior portion of the diencephalon, forms the inferolateral walls of the third ventricle”
optic chiasma
point of crossover of cranial nerves II, the optic nerves), (on one side of the hypothalamus)
mammillary bodies
”"”little breast””, rounded bumps that bulge from the hypothalamic floor, anterior to the hypothalamus”
epithalamus
third and most dorsal part of the diencephalon, forms part of the roof of the third ventricle, consists of one tiny group of brain nuclei and a small unpaired knob called the pineal gland
pineal gland
derives from ependymal glial cells, hormone-secreting organ, secretes melatonin
melatonin
hormone that signals the body to prepare for the nighttime stage of the sleep-wake cycle
transverse cerebral fissure
spearaptes the cerebral hemispheres from the cerebellum inferiorly
logitudinal fissure
separates the right and left cerebral hemispheres from each other
sulci
(sulcus=furrow), shallow grooves on the surface of the cerebral hemispheres
gyri
(gyrus=twister), twisted ridges of brain tissue between the sulci
frontal lobe
located deep to the frontal bone and fills the anterior cranial fossa, contains functional areas that plan, initiate, and enact motor movement including eye movement and speech production, the most anterior region performs higher-order cognitive functions, such as thinking, planning, decision making, working memory, and other executive functions
central sulcus
separates the frontal lobe from the parietal lobe
precentral gyrus
contains the primary motor cortex, lies just anterior to the central sulcus
parietal lobe
deep to the parietal bones, processes sensory stimula allowing 1) conscious awareness of general somatic sensation, 2) spacial awareness of objects, sounds, and body parts, and 3) understanding of speech
parieto-occipital sulcus
marks the posterior boundary of the parietal lobe
lateral sulcus
forms the inferior boundary of the parietal lobe, separates the temporal lobe from the overlying parietal and frontal lobes
postcentral gyrus
just posterior to the central sulcus, contains the primary somatosensory cortex
occipital lobe
lies deep to the occipital bone and forms the most posterior portion of the cerebrum; contains the visual cortex
temporal lobe
lateral side of the hemisphere, lies in the middle cranial fossa deep to the temporal bone, contains the auditory cortex and the olfactory cortex and functions in the crecognition of objects, words, and faces, in language comprehension, and in emotional response and memory
insula
”"”island””, buried deep within the lateral sulcus and forms part of its floor, covered by parts of the temporal, parietal, and frontal lobes, contains the visceral sensory cortex for taste and general visceral sensations”
primary sensory cortex
sensory area for each of the major senses
sensory association areas
each primary sensory cortex has association areas linked to it that process the sensory information
multimodal asseciation areas
association areas that receive and integrate input from multiple regions of the cerebral cortex
motor areas
regions of the cortex that plan and initiate voluntary motor functions
primary somatosensory cortex
receives information from the geeral somatic senses (touch, pressure, vibration, pain, and temperature from the skin and proprieception from the muscles and joints) and enables conscious awareness of these sensations
sensory homunculus
”"”little man””, map of the primary sensory cortex”
contralateral projection
the right cerebral hemisphere receives its sensory input from the left side of the body and the left cerebral hemisphere receives its sensory input from the right side of the body
somatosensory association cortex
lies posterior to and communicates with the primary somatosensory cortex, integrates sensory inputs (touch, pressure, and others) into a comprehensive understand of what is being felt
primary visual cortex
“posterior and medial part of the occipital lobe, much of it buried within the deep carcarine sulcus (““spur-shaped””), receives visual information that originates from the retina of the eye, exhibits contralateral projection”
visual association area
surrounds that primary visual cortex and covers much of the occipital lobe, continues the processing of visual information by analyzing color, form, and movement
primary auditotry cortex
functions in censcious awareness of sound, in relation to loudness, rhythm, and pitch, located on teh superior edge of the temporal lobe, primarily inside the lateral sulcus
auditory association area
lies just posterior and lateral to the primary auditory area, permits the evaluation of a sound
vestibular (equilibrium) cortex
responsible for conscious awareness of the sense of balance, specifically the awareness of the position of the head in space, located in the posterior part of the insula deep to the lateral sulcus
gustatory cortex
lies in the insula, involved in the conscious awareness of taste stimuli
olfactory cortex
lies on the medial aspect of the temporal lobe in a small region called the piriform cortex, which is dominated by the hooklike uncus, results in conscious awareness of smells
rhinencephalon
”"”nose brain””, includes all parts of the cerebrum that directly receive olfactory signals: the piriform cortex, the olfactory tract, the olfactory bulb, and some nearby structures”
visceral sensory area
located deep within the lateral sulcus on the insula, receives general sensory inut (pain, pressure, hunger, and so forth) from the thoracic and abdominal organs
primary motor cortex
located along the precentral gyrus of the frontal lobe just anterior to the primary sensory cortex, bring about precise voluntary movements of the body, especially of the forearms, fingers, and facial muscles, the projection is contralateral
pyramidal cells
large neurons in the primary motor cortex
pyramidal tracts
long axons of pyramidal cells that descend through the brain stem and spinal cord
motor homunculus
represents the human body spatially in the primary motor cortex of each hemisphere
premotor cortex
plans and coordinates complex movements and relays the plan to the primary motor cortex for implementation, just anterior to the precentral gyrus
frontal eye field
lies anterior to the premotor cortex, controls voluntary movements of the eyes
“Broca’s area”
lies anterior to the inferior part of the premotor cortex in the left, or language-dominant, cerebral hemisphere, controls the motor movements necessary for speaking
multimodal association areas
large regions of the cerbral cortex that receive sensory input from multiple sensory modalities and from the sensory association areas, ties together various kinds of sensory information and associates new sensory inputs with memories of past experiences and plans appropriate motor responses
posterior association area
located at the interface of the visual, auditory, and somatosensory association areas in the parietal and temporal lobes, integrates all these types of sensory information to form a unified perception of the sensory input
dorsal stream
“extends through the posterior parietal cortex to the postcentral gyrus and perceives spatial relationships among various objects (““where”” pathway)”
ventral stream
“extends through the inferior part of the temporal lobe and is responsible for recognizing objects, words during reading, and faces (““what”” pathway)”
anterior association area (prefrontal cortex)
large anterior region of the frontal lobe, receives highly processed sensory information from the posterior association area, integrates this information with past experience through connection with the limbic asseciation area, and plans and initiates motor responses through linkage with the motor regions
limbic association area
located on the medial side of the cerbral hemispheres in portions of the temporal, parietal and frontal lobes and includes the cingulate gyrus, the hippocampus, and parahipocampal gurus; involved in both memory and emotion, integrates sensory and motor behavior with past experience, helps form memory, and uses this past experience to influence future motor response
commissural fibers
cross from one side of the CNS to the other, e.g. connect the left and right cerebral hemispheres allowing the two hemispheres to function together as a coordinated whole
corpus callosum
”"”thickened body””, largest commissure, a broad band that lies superior to the lateral ventricles, deep within the longitudinal fissure”
association fibers
connect different parts of the same hemisphere
projection fibers
either descend from the cerebral cortex to more caudal parts of the CNS or ascend to the cortex from lower regions, fibers run vertically
internal capsule
projection fibers form a compact bundle deep to the cerebral white matter which passes between the thalamus and some of the deep gray matter, the basal nuclei
corona radiata
”"”radiating crown””, superior to the internal capsule, the projection fibers running to and from the cerebral cortex fan out”
basal nuclei
complex neural calculators that cooperate with the cerebral cortex in controlling movements
basal forebrain nuclei
septal nuclei, diagonal band (of Broca), horizontal band (of Broca), basal nucleus (of Meynert); functions related to arousal, learning, memory, and motor control
fornix
”"”arch””, with other fiber tracts, link the limbic system together”
cingulate gyrus
”"”belt-shaped””, part of the cerebral cortex located superior to the corpus callosum, mediates the emotional response to stimuli”
hippocampal formation
“consists of the hippocampus (““sea horse””) and the parahyppocampal gyrus, endcode, consolidate, and later retrive memories of facts and events”
amygdaloid body
subjortical gray matter that contains the key brain nuclei for processing fear and stimulating the appropriate sympathetic response to fear, forms memories of experiences based entirely on their emotional impact
reticular activating system (RAS)
arm of the reticular formation which maintains consciousness and alertness, located mainly in the medial nuclear group of the pons and medulla in the brain stem
meninges
three connective tissue membranes that lie just external to the brain and spinal cord
periosteal layer
more superficial layer of the dura mater, attaches to the internal surface of the skull bones (it is the periosteum)
meningeal layer
deeper layer of the dura mater, forms the true external covering of the brain
falx cerebri
(falx=sickle), vertical sheet lies in the median plane in the longitudinal fissure between the cerebral hemispheres, attaches anteriorly to the crista galli of the ethmoid bone
falx cerebelli
continuing inferiorly from the posterior part of the falx cerebri, the _ is a vertiacal partition that runs along the vermis of the cerebellum in the posterior cranial fossa
tentorium cerebelli
”"”tentorium=tent””, almost horizontal sheet lies in the transvese fissure between the cerebrum and cerebellum, transverse sinus is enclosed by the _”
arachnoid mater
lies just deep to the dura mater
subdural space
between the arachnoid matera nd the dura mater is a thin potential space which contains only a film of fluid
subarachnoid space
spanned by weblike threads that hold the arachnoid mater to the underlying pia mater, filled with cerebrospinal fluid and contains the largest blood vessels that supply the brain
arachnoid granulations
aka arachnoid villi, project superiorly through the dura mater into the superior sagittal sinus and into some other dural sinuses as well, act as valves that allow cerebrospinal fluid to pass from the subarachnoid space into teh dural venous sinuses
pia mater
”"”gentle mother””, layer of delicate connective tissue richly vascularized with fine blood vessels, clings tightly to the brain surface following every convolution”
cerebrospinal fluid (CSF)
watery broth that fills the subarachnoid space and the central hollow cavities of the brain and spinal cord, aids in protecting and nourishing the neural tissue
choroid plexuses
capillary-rich membranes located in the roofs of the four brain ventricles that make CSF
blood brain barrier
results primarily from special features of the epithelium that make up the walls of the brain capillaries, prevent bloodborne toxins (e.g. urea, mild toxins from food, and bacterial toxins) from entering brain tissue
conus medullaris
”"”cone of the spinal cord””, spinal cord tapers at its inferior end into the _”
filum terminale
”"”end filament””, a long filament of cennective tissue that extends from the conus medullaris and attaches to the coccyx inferiorly, anchoring the spinal cord in place so that it is not jostled by body movements”
cervical and lumbar enlargements
obvious enlagements of the spinal cord in the cervical and lumbar regions where the nerves to the upper and lower limbs arise
cauda equina
”"”horse’s tail””, collection of nerve roots at the inferior end of the vertebral canal”
spinal cord segment
the region of the spinal cord from which the axonal processes that form a given spinal nerve emerge
dorsal (posterior) mediansulcus and ventral (anterior) median fissure
two grooves that run the length of the cord and partly divide it into right and left halves
ascending fibers
most of the _ in the spinal cord carry sensory information from the sensory neurons of the body up to the brain
descending fibers
“most _ carry motor instructions from the brain to the spinal cord, to stimulate contraction of the body’s muscles and secretion from its glands”
commisural fibers
white-matter fibers that carry information from one side of the spinal cord to the other
gray commissure
crossbar of the H, composed of unmyeliated axons that cross from one side of the cNS to the other
