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Key Terms Chapter 13: Anatomy of Nervous System

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    abducens nerve
    sixth cranial nerve; responsible for contraction of one of the extraocular muscles
    alar plate
    developmental region of the spinal cord that gives rise to the posterior horn of the gray matter
    amygdala
    nucleus deep in the temporal lobe of the cerebrum that is related to memory and emotional behavior
    anterior column
    white matter between the anterior horns of the spinal cord composed of many different groups of axons of both ascending and descending tracts
    anterior horn
    gray matter of the spinal cord containing multipolar motor neurons, sometimes referred to as the ventral horn
    anterior median fissure
    deep midline feature of the anterior spinal cord, marking the separation between the right and left sides of the cord
    anterior spinal artery
    blood vessel from the merged branches of the vertebral arteries that runs along the anterior surface of the spinal cord
    arachnoid granulation
    outpocket of the arachnoid membrane into the dural sinuses that allows for reabsorption of CSF into the blood
    arachnoid mater
    middle layer of the meninges named for the spider-web–like trabeculae that extend between it and the pia mater
    arachnoid trabeculae
    filaments between the arachnoid and pia mater within the subarachnoid space
    ascending tract
    central nervous system fibers carrying sensory information from the spinal cord or periphery to the brain
    axillary nerve
    systemic nerve of the arm that arises from the brachial plexus
    basal forebrain
    nuclei of the cerebrum related to modulation of sensory stimuli and attention through broad projections to the cerebral cortex, loss of which is related to Alzheimer’s disease
    basal nuclei
    nuclei of the cerebrum (with a few components in the upper brain stem and diencephalon) that are responsible for assessing cortical movement commands and comparing them with the general state of the individual through broad modulatory activity of dopamine neurons; largely related to motor functions, as evidenced through the symptoms of Parkinson’s and Huntington’s diseases
    basal plate
    developmental region of the spinal cord that gives rise to the lateral and anterior horns of gray matter
    basilar artery
    blood vessel from the merged vertebral arteries that runs along the dorsal surface of the brain stem
    brachial plexus
    nerve plexus associated with the lower cervical spinal nerves and first thoracic spinal nerve
    brain stem
    region of the adult brain that includes the midbrain, pons, and medulla oblongata and develops from the mesencephalon, metencephalon, and myelencephalon of the embryonic brain
    Broca’s area
    region of the frontal lobe associated with the motor commands necessary for speech production and located only in the cerebral hemisphere responsible for language production, which is the left side in approximately 95 percent of the population
    Brodmann’s areas
    mapping of regions of the cerebral cortex based on microscopic anatomy that relates specific areas to functional differences, as described by Brodmann in the early 1900s
    carotid canal
    opening in the temporal bone through which the internal carotid artery enters the cranium
    cauda equina
    bundle of spinal nerve roots that descend from the lower spinal cord below the first lumbar vertebra and lie within the vertebral cavity; has the appearance of a horse's tail
    caudate
    nucleus deep in the cerebrum that is part of the basal nuclei; along with the putamen, it is part of the striatum
    central canal
    hollow space within the spinal cord that is the remnant of the center of the neural tube
    central sulcus
    surface landmark of the cerebral cortex that marks the boundary between the frontal and parietal lobes
    cephalic flexure
    curve in midbrain of the embryo that positions the forebrain ventrally
    cerebellum
    region of the adult brain connected primarily to the pons that developed from the metencephalon (along with the pons) and is largely responsible for comparing information from the cerebrum with sensory feedback from the periphery through the spinal cord
    cerebral aqueduct
    connection of the ventricular system between the third and fourth ventricles located in the midbrain
    cerebral cortex
    outer gray matter covering the forebrain, marked by wrinkles and folds known as gyri and sulci
    cerebral hemisphere
    one half of the bilaterally symmetrical cerebrum
    cerebrum
    region of the adult brain that develops from the telencephalon and is responsible for higher neurological functions such as memory, emotion, and consciousness
    cervical plexus
    nerve plexus associated with the upper cervical spinal nerves
    choroid plexus
    specialized structures containing ependymal cells lining blood capillaries that filter blood to produce CSF in the four ventricles of the brain
    circle of Willis
    unique anatomical arrangement of blood vessels around the base of the brain that maintains perfusion of blood into the brain even if one component of the structure is blocked or narrowed
    common carotid artery
    blood vessel that branches off the aorta (or the brachiocephalic artery on the right) and supplies blood to the head and neck
    corpus callosum
    large white matter structure that connects the right and left cerebral hemispheres
    cranial nerve
    one of twelve nerves connected to the brain that are responsible for sensory or motor functions of the head and neck
    cranial nerve ganglion
    sensory ganglion of cranial nerves
    descending tract
    central nervous system fibers carrying motor commands from the brain to the spinal cord or periphery
    diencephalon
    region of the adult brain that retains its name from embryonic development and includes the thalamus and hypothalamus
    direct pathway
    connections within the basal nuclei from the striatum to the globus pallidus internal segment and substantia nigra pars reticulata that disinhibit the thalamus to increase cortical control of movement
    disinhibition
    disynaptic connection in which the first synapse inhibits the second cell, which then stops inhibiting the final target
    dorsal (posterior) nerve root
    axons entering the posterior horn of the spinal cord
    dorsal (posterior) root ganglion
    sensory ganglion attached to the posterior nerve root of a spinal nerve
    dura mater
    tough, fibrous, outer layer of the meninges that is attached to the inner surface of the cranium and vertebral column and surrounds the entire CNS
    dural sinus
    any of the venous structures surrounding the brain, enclosed within the dura mater, which drain blood from the CNS to the common venous return of the jugular veins
    endoneurium
    innermost layer of connective tissue that surrounds individual axons within a nerve
    enteric nervous system
    peripheral structures, namely ganglia and nerves, that are incorporated into the digestive system organs
    enteric plexus
    neuronal plexus in the wall of the intestines, which is part of the enteric nervous system
    epineurium
    outermost layer of connective tissue that surrounds an entire nerve
    epithalamus
    region of the diecephalon containing the pineal gland
    esophageal plexus
    neuronal plexus in the wall of the esophagus that is part of the enteric nervous system
    extraocular muscles
    six skeletal muscles that control eye movement within the orbit
    facial nerve
    seventh cranial nerve; responsible for contraction of the facial muscles and for part of the sense of taste, as well as causing saliva production
    fascicle
    small bundles of nerve or muscle fibers enclosed by connective tissue
    femoral nerve
    systemic nerve of the anterior leg that arises from the lumbar plexus
    fibular nerve
    systemic nerve of the posterior leg that begins as part of the sciatic nerve
    foramen magnum
    large opening in the occipital bone of the skull through which the spinal cord emerges and the vertebral arteries enter the cranium
    forebrain
    anterior region of the adult brain that develops from the prosencephalon and includes the cerebrum and diencephalon
    fourth ventricle
    the portion of the ventricular system that is in the region of the brain stem and opens into the subarachnoid space through the median and lateral apertures
    frontal eye field
    region of the frontal lobe associated with motor commands to orient the eyes toward an object of visual attention
    frontal lobe
    region of the cerebral cortex directly beneath the frontal bone of the cranium
    gastric plexuses
    neuronal networks in the wall of the stomach that are part of the enteric nervous system
    globus pallidus
    nuclei deep in the cerebrum that are part of the basal nuclei and can be divided into the internal and external segments
    glossopharyngeal nerve
    ninth cranial nerve; responsible for contraction of muscles in the tongue and throat and for part of the sense of taste, as well as causing saliva production
    gyrus
    ridge formed by convolutions on the surface of the cerebrum or cerebellum
    hindbrain
    posterior region of the adult brain that develops from the rhombencephalon and includes the pons, medulla oblongata, and cerebellum
    hippocampus
    gray matter deep in the temporal lobe that is very important for long-term memory formation
    hypoglossal nerve
    twelfth cranial nerve; responsible for contraction of muscles of the tongue
    hypothalamus
    major region of the diencephalon that is responsible for coordinating autonomic and endocrine control of homeostasis
    indirect pathway
    connections within the basal nuclei from the striatum through the globus pallidus external segment and subthalamic nucleus to the globus pallidus internal segment/substantia nigra pars compacta that result in inhibition of the thalamus to decrease cortical control of movement
    inferior colliculus
    half of the midbrain tectum that is part of the brain stem auditory pathway
    inferior olive
    nucleus in the medulla that is involved in processing information related to motor control
    intercostal nerve
    systemic nerve in the thoracic cavity that is found between two ribs
    internal carotid artery
    branch from the common carotid artery that enters the cranium and supplies blood to the brain
    interventricular foramina
    openings between the lateral ventricles and third ventricle allowing for the passage of CSF
    jugular veins
    blood vessels that return “used” blood from the head and neck
    kinesthesia
    general sensory perception of movement of the body
    lateral apertures
    pair of openings from the fourth ventricle to the subarachnoid space on either side and between the medulla and cerebellum
    lateral column
    white matter of the spinal cord between the posterior horn on one side and the axons from the anterior horn on the same side; composed of many different groups of axons, of both ascending and descending tracts, carrying motor commands to and from the brain
    lateral horn
    region of the spinal cord gray matter in the thoracic, upper lumbar, and sacral regions that is the central component of the sympathetic division of the autonomic nervous system
    lateral sulcus
    surface landmark of the cerebral cortex that marks the boundary between the temporal lobe and the frontal and parietal lobes
    lateral ventricles
    portions of the ventricular system that are in the region of the cerebrum
    limbic cortex
    collection of structures of the cerebral cortex that are involved in emotion, memory, and behavior and are part of the larger limbic system
    limbic system
    structures at the edge (limit) of the boundary between the forebrain and hindbrain that are most associated with emotional behavior and memory formation
    longitudinal fissure
    large separation along the midline between the two cerebral hemispheres
    lumbar plexus
    nerve plexus associated with the lumbar spinal nerves
    lumbar puncture
    procedure used to withdraw CSF from the lower lumbar region of the vertebral column that avoids the risk of damaging CNS tissue because the spinal cord ends at the upper lumbar vertebrae
    median aperture
    singular opening from the fourth ventricle into the subarachnoid space at the midline between the medulla and cerebellum
    median nerve
    systemic nerve of the arm, located between the ulnar and radial nerves
    meninges
    protective outer coverings of the CNS composed of connective tissue
    mesencephalon
    primary vesicle of the embryonic brain that does not significantly change through the rest of embryonic development and becomes the midbrain
    metencephalon
    secondary vesicle of the embryonic brain that develops into the pons and the cerebellum
    midbrain
    middle region of the adult brain that develops from the mesencephalon
    myelencephalon
    secondary vesicle of the embryonic brain that develops into the medulla
    nerve plexus
    network of nerves without neuronal cell bodies included
    neural crest
    tissue that detaches from the edges of the neural groove and migrates through the embryo to develop into peripheral structures of both nervous and non-nervous tissues
    neural fold
    elevated edge of the neural groove
    neural groove
    region of the neural plate that folds into the dorsal surface of the embryo and closes off to become the neural tube
    neural plate
    thickened layer of neuroepithelium that runs longitudinally along the dorsal surface of an embryo and gives rise to nervous system tissue
    neural tube
    precursor to structures of the central nervous system, formed by the invagination and separation of neuroepithelium
    neuraxis
    central axis to the nervous system, from the posterior to anterior ends of the neural tube; the inferior tip of the spinal cord to the anterior surface of the cerebrum
    occipital lobe
    region of the cerebral cortex directly beneath the occipital bone of the cranium
    occipital sinuses
    dural sinuses along the edge of the occipital lobes of the cerebrum
    oculomotor nerve
    third cranial nerve; responsible for contraction of four of the extraocular muscles, the muscle in the upper eyelid, and pupillary constriction
    olfaction
    special sense responsible for smell, which has a unique, direct connection to the cerebrum
    olfactory nerve
    first cranial nerve; responsible for the sense of smell
    optic nerve
    second cranial nerve; responsible for visual sensation
    orthostatic reflex
    sympathetic function that maintains blood pressure when standing to offset the increased effect of gravity
    paravertebral ganglia
    autonomic ganglia superior to the sympathetic chain ganglia
    parietal lobe
    region of the cerebral cortex directly beneath the parietal bone of the cranium
    parieto-occipital sulcus
    groove in the cerebral cortex representing the border between the parietal and occipital cortices
    perineurium
    layer of connective tissue surrounding fascicles within a nerve
    phrenic nerve
    systemic nerve from the cervical plexus that innervates the diaphragm
    pia mater
    thin, innermost membrane of the meninges that directly covers the surface of the CNS
    plexus
    network of nerves or nervous tissue
    postcentral gyrus
    primary motor cortex located in the frontal lobe of the cerebral cortex
    posterior columns
    white matter of the spinal cord that lies between the posterior horns of the gray matter, sometimes referred to as the dorsal column; composed of axons of ascending tracts that carry sensory information up to the brain
    posterior horn
    gray matter region of the spinal cord in which sensory input arrives, sometimes referred to as the dorsal horn
    posterior median sulcus
    midline feature of the posterior spinal cord, marking the separation between right and left sides of the cord
    posterolateral sulcus
    feature of the posterior spinal cord marking the entry of posterior nerve roots and the separation between the posterior and lateral columns of the white matter
    precentral gyrus
    ridge just posterior to the central sulcus, in the parietal lobe, where somatosensory processing initially takes place in the cerebrum
    prefrontal lobe
    specific region of the frontal lobe anterior to the more specific motor function areas, which can be related to the early planning of movements and intentions to the point of being personality-type functions
    premotor area
    region of the frontal lobe responsible for planning movements that will be executed through the primary motor cortex
    prevertebral ganglia
    autonomic ganglia that are anterior to the vertebral column and functionally related to the sympathetic chain ganglia
    primary vesicle
    initial enlargements of the anterior neural tube during embryonic development that develop into the forebrain, midbrain, and hindbrain
    proprioception
    general sensory perceptions providing information about location and movement of body parts; the “sense of the self”
    prosencephalon
    primary vesicle of the embryonic brain that develops into the forebrain, which includes the cerebrum and diencephalon
    putamen
    nucleus deep in the cerebrum that is part of the basal nuclei; along with the caudate, it is part of the striatum
    radial nerve
    systemic nerve of the arm, the distal component of which is located near the radial bone
    reticular formation
    diffuse region of gray matter throughout the brain stem that regulates sleep, wakefulness, and states of consciousness
    rhombencephalon
    primary vesicle of the embryonic brain that develops into the hindbrain, which includes the pons, cerebellum, and medulla
    sacral plexus
    nerve plexus associated with the lower lumbar and sacral spinal nerves
    saphenous nerve
    systemic nerve of the lower anterior leg that is a branch from the femoral nerve
    sciatic nerve
    systemic nerve from the sacral plexus that is a combination of the tibial and fibular nerves and extends across the hip joint and gluteal region into the upper posterior leg
    sciatica
    painful condition resulting from inflammation or compression of the sciatic nerve or any of the spinal nerves that contribute to it
    secondary vesicle
    five vesicles that develop from primary vesicles, continuing the process of differentiation of the embryonic brain
    sigmoid sinuses
    dural sinuses that drain directly into the jugular veins
    somatosensation
    general senses related to the body, usually thought of as the senses of touch, which would include pain, temperature, and proprioception
    spinal accessory nerve
    eleventh cranial nerve; responsible for contraction of neck muscles
    spinal nerve
    one of 31 nerves connected to the spinal cord
    straight sinus
    dural sinus that drains blood from the deep center of the brain to collect with the other sinuses
    striatum
    the caudate and putamen collectively, as part of the basal nuclei, which receive input from the cerebral cortex
    subarachnoid space
    space between the arachnoid mater and pia mater that contains CSF and the fibrous connections of the arachnoid trabeculae
    subcortical nucleus
    all the nuclei beneath the cerebral cortex, including the basal nuclei and the basal forebrain
    substantia nigra pars compacta
    nuclei within the basal nuclei that release dopamine to modulate the function of the striatum; part of the motor pathway
    substantia nigra pars reticulata
    nuclei within the basal nuclei that serve as an output center of the nuclei; part of the motor pathway
    subthalamus
    nucleus within the basal nuclei that is part of the indirect pathway
    sulcus
    groove formed by convolutions in the surface of the cerebral cortex
    superior colliculus
    half of the midbrain tectum that is responsible for aligning visual, auditory, and somatosensory spatial perceptions
    superior sagittal sinus
    dural sinus that runs along the top of the longitudinal fissure and drains blood from the majority of the outer cerebrum
    sympathetic chain ganglia
    autonomic ganglia in a chain along the anterolateral aspect of the vertebral column that are responsible for contributing to homeostatic mechanisms of the autonomic nervous system
    systemic nerve
    nerve in the periphery distal to a nerve plexus or spinal nerve
    tectum
    region of the midbrain, thought of as the roof of the cerebral aqueduct, which is subdivided into the inferior and superior colliculi
    tegmentum
    region of the midbrain, thought of as the floor of the cerebral aqueduct, which continues into the pons and medulla as the floor of the fourth ventricle
    telencephalon
    secondary vesicle of the embryonic brain that develops into the cerebrum
    temporal lobe
    region of the cerebral cortex directly beneath the temporal bone of the cranium
    terminal ganglion
    autonomic ganglia that are near or within the walls of organs that are responsible for contributing to homeostatic mechanisms of the autonomic nervous system
    thalamus
    major region of the diencephalon that is responsible for relaying information between the cerebrum and the hindbrain, spinal cord, and periphery
    third ventricle
    portion of the ventricular system that is in the region of the diencephalon
    tibial nerve
    systemic nerve of the posterior leg that begins as part of the sciatic nerve
    transverse sinuses
    dural sinuses that drain along either side of the occipital–cerebellar space
    trigeminal ganglion
    sensory ganglion that contributes sensory fibers to the trigeminal nerve
    trigeminal nerve
    fifth cranial nerve; responsible for cutaneous sensation of the face and contraction of the muscles of mastication
    trochlear nerve
    fourth cranial nerve; responsible for contraction of one of the extraocular muscles
    ulnar nerve
    systemic nerve of the arm located close to the ulna, a bone of the forearm
    vagus nerve
    tenth cranial nerve; responsible for the autonomic control of organs in the thoracic and upper abdominal cavities
    ventral (anterior) nerve root
    axons emerging from the anterior or lateral horns of the spinal cord
    ventricles
    remnants of the hollow center of the neural tube that are spaces for cerebrospinal fluid to circulate through the brain
    vertebral arteries
    arteries that ascend along either side of the vertebral column through the transverse foramina of the cervical vertebrae and enter the cranium through the foramen magnum
    vestibulocochlear nerve
    eighth cranial nerve; responsible for the sensations of hearing and balance
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