Ch. 14: NS Spinal Cord and Spinal Nerves

-Spinal cord is associated w how many pairs of spinal nerves? -Spinal nerves are identified through what two things? -How many cervical nerves are there? Thoracic?

-31 pairs -First letter of spinal cord part to which it attaches and then number -8 Cervical = C1-C8 -12 Thoracic = T1-T12

-Lumbar nerves? Sacral? Coccygeal? -Each spinal nerve anchors to the spinal cord by 2 roots, a posterior root and anterior root, each having multiple? -Houses sensory neurons that extend from sensory receptors, relay nerve signals from sensory receptors to the spinal cord? -Sensory neurons that compose spinal nerves are called?

-5 Lumbar = L1-L5 -5 Sacral = S1-S5 -1 Coccygeal = Co1 -Rootlets -Posterior roots -Unipolar neurons

-Seven cervical spinal nerves exit vertebral canal and extend through intervertebral foramen that is superior to the vertebra of the same #? -ex: C2 spinal nerve exits vertebral canal through intervertebral foramen bw C1 and C2 vertebrae -In conclusion, the 8th cervical spinal nerve exits intervertebral foramen? -All remaining spinal nerves inferior to C8 nerve exit vertebral canal and extend through intervertebral foramen?

-8 cervical nerves facts -Inferior to the C7 vertebra -Inferior to vertebra of same #

-The cross sections of each spinal cord part in the different sections of the spinal cord differ in what way? -All of the series of neurons + associated structures that relay signals bw brain and body? -Can be identified as what depending on direction nerve signals are relayed relative to brain?

-Amt of gray/white matter and shape, depending on the need for more neuron cell bodies that have axons extending to innervate specific areas -Conduction pathway -Sensory or motor

-If patient experiences this, along medial side of arm/forearm, C8 spinal nerve may be damaged? -Phenomenon in which pain/discomfort from one organ is mistakenly referred to a dermatome? -Network of interweaving anterior rami of spinal nerves, forms on both l/r sides of body, splits into multiple named nerves?

-Anesthesia -Referred visceral pain -Nerve plexus

-Motor branches: -Innervates geniohyoid, infrahyoid muscles (omohyoid, sternohyoid, sternothyroid, and thyrohyoid)? -Innervates anterior and middle scalenes? -Cutaneous branches: -Innervates skin on ear, CT capsule covering parotid gland?

-Ansa cervicalis: Superior root (C1/C2) + Inferior root (C2/C3) -Segmental branches (C1-C4) -greater auricular (C2/C3)

-Portions of each trunk divide deep to clavicle into what two divisions that have axons that innervate anterior/posterior parts of upper limb? -At axilla, anterior/posterior divisions converge to form 3 cords: -Posterior to axillary artery and is formed by posterior divisions of superior, middle, and inferior trunks, portions of C5-T1? -Medial to axillary artery, formed by anterior division of inferior trunk, C8-T1?

-Anterior and posterior division -Posterior cord -Medial cord

-Composed of white matter that occupies the space on each anterior side of the cord bw anterior gray horns and anterior median fissure? -Thing above interconnected by? -Axons w/in each funiculus organized into smaller units called? -White matter on each side of cord can be referred to as these which have common functions, myelinated axons w common origin, destination, and function?

-Anterior funiculus -White commissure -Fasciculi -Tracts

-Both l/r anterior masses of gray matter, GM due to presence of dendrites/cell bodies of somatic motor neurons? -Collectively, thing above forms this which forms entire anterior horn on each side of spinal cord? -Axons of what extend to and innervate a somatic effector? -Somatic effector includes only muscles that can be controlled consciously or?

-Anterior horns -Somatic motor nuclei -Somatic motor neurons -Voluntarily

-Innervate not only inferior intercostal spaces but abdominal muscles and overlying skin? -Left and right this located deep on each side of neck, immediately lateral to cervical vertebrae C1-C4, formed by anterior rami of spinal nerves C1-C4? -Branches of this innervate anterior neck muscles, skin of neck, portions of head and shoulders -Indicates portion that relays motor output to SM? -Indicates portion relays sensory input from skin?

-Anterior rami of nerves T7-T12 -Cervical plexuses -Motor branches, Cutaneous branches

-Uses chain of three neurons to communicate w brain of specific stimulus, pathway originates @ tactile somatosensory receptor, provides info to brain about crude touch and pressure as well as pain and temperature? -Sensations that require us to act in response to stimulus like an itch or tickling? -Extends from somatosensory receptor in spinal cord via posterior root, synapses w secondary in posterior horn in SPINAL CORD? -Extends from spinal cord to thalamus, axons project in spinothalamic tract in anterior funiculus or lateral funiculus to the thalamus, which filters incoming sensory input?

-Anterolateral pathway/spinothalamic pathway -Axon of primary neuron in AL path -Axon of secondary neuron in AL path

-Traverses through axilla and posterior to surgical neck of humerus, innervates deltoid and teres minor muscles, receives sensory nerve signals from superolateral part of arm -C5,C6, formed from posterior cord

-Axillary nerve

-Extends from proprioceptor into spinal cord via posterior roots, this synapses w secondary neuron w/in posterior horn of spinal cord? -Extends from spinal cord within spinocerebellar tract either w/in anterior/posterior part of lateral funiculus? -Names of pathway derived from origin of tracts that ascend from spinal cord to cerebellum?

-Axon of primary neuron of Spinocerebellar path -Axon of secondary neuron of SC pathway -Spinocerebellar pathway

-Extends from medulla oblongata and projects within the medial lemniscus to the thalamus, which filters incoming sensory input? -Extends from thalamus to the cerebrum, conscious perception of tactile/proprioceptor sensory input occurs w/in parietal lobe?

-Axon of secondary neuron in PFML -Axon of tertiary neuron

-Extends from thalamus to cerebrum, conscious perception of tactile/proprioceptor sensory input occurs w/in parietal lobe? -Name of pathway derived from location of 2 funiculi through which it ascends, anterior/lateral funiculus, secondary name from tracts that relay nerve signals w/in spinal cord to thalamus? -Uses a chain of only 2 neurons to communicate w brain about specific stimulus, originates at proprioceptors in joints, muscles, and tendons @ different locations in body -Provides info related to postural input, helps maintaining balance and posture?

-Axon of tertiary neuron -Anterolateral/spinothalamic pathway -Spinocerebellar pathway

-C5, C6, Flexes elbow when biceps brachii tendon is tapped? -C6-C7, extends elbow when triceps brachii tendon is tapped? -T8-T12, contract abdominal muscles when one side of abdominal wall is briskly stroked? -L1-L2, Elevates testis when medial side of thigh is briskly stroked?

-Biceps reflex -Triceps reflex -Abdominal reflexes -Cremasteric reflexes

-L/r networks of nerves that supply the upper limb, formed by anterior rami of spinal nerves C5-T1, extend laterally from neck, past superior rib, and into axilla? -Brachial plexus structures: -Continuations of anterior rami of spinal nerves C5-T1, emerge through intervertebral foramina and extend the neck? -Five rami above unites in posterior triangle of neck to form?

-Brachial plexuses -Anterior rami, roots -Superior, middle, and inferior trunks

-Each spinal nerve except for which two, extend through an intervertebral foramen to exits the vertebral column? -Each nerve splits almost immediately into two primary branches, termed? -Smaller of the two branches, innervates deep muscles of the back like erector spinae or transversospinalis and skin of back? -Larger of two main branches, splits into multiple branches that innervate skin/SM of anterior/lateral portions of trunk, upper/lower limbs, go on to form nerve plexuses?

-C1 and Co1 -Rami -Posterior/dorsal ramus -Anterior/ventral ramus

-What part of the neural tube forms the spinal cord? -A hollow neural canal in neural tube develops into central canal and grows at a rapid rate, during 4th/5th week, neural tube grows rapidly and unevenly, forms outer white matter and inner gray matter?

-Caudal/inferior part -Process of spinal cord development

-Wider area in the cervical part? -Wider area in lumbar/sacral parts? -Why are these parts larger?

-Cervical enlargement -Lumbosacral enlargement -Due to presence of more neurons in spinal nerves that extend from these spinal cord parts

-L4-S2, Formed from posterior division of sciatic nerve, innervates short head of biceps femoris muscle, on lateral knee, wraps around neck of fibula, splits into deep fibular nerve and superficial fibular nerve? -L4-S1, extends through anterior compartment of leg and end bw first and second toes, innervates anterior leg muscles and dorsum of foot, receives input from 1st/2nd toes? -L5-S2, extends through lateral part of leg, proximal to ankle, nerve = superficial on anterior part of ankle/dorsum of foot, innervates lateral part of muscles of leg, foot evertors/weak plantar flexors, receives sensory input from dorsal surface/anteroinferior part of leg?

-Common fibular/peroneal nerve -Deep fibular/peroneal nerve -Superficial fibular/peroneal nerve

-Neuron cell bodies located in one of 3 gen places: posterior root ganglion, gray horns in spinal cord, or nuclei in brain on pathway? -Axons of diff neurons extend through spinal nerves, spinal cord, and brain? -Neurons cross over or decussate, forming an x from one side of body to other at some points in brain/spinal cord?

-Common location of neuron cell bodies -Common location of axons -Decussation

-Reflex that involves an effector on the opposite side of body from receptor that detected stimulus, only applicable to limbs where left foot gets withdrawn with the right counteracting it with balance? -Reflex classified based upon whether one is born w it: -Reflex that one is born with? -Reflex is one that is developed after birth?

-Contralateral reflex -Innate reflex -Acquired reflex

-Occurs in conjunction w withdrawal reflex usually in lower weight-bearing limbs, helps to maintain balance and shift body weight accordingly? -When sensory neurons transmit nerve signals to spinal cord, some branches synapse w interneurons involved in stretch reflex, other synapse w interneurons involved with this reflex?

-Crossed-extensor reflex

-Where brain on left side receives sensory input from/initiates motor output to right side of body, and vice-versa? -Used to indicate relationship to opposite side? -Pathways have some neurons that remain on same side of body, term used to indicate relationship to same side?

-Decussation -Contralateral -Limited ipsilateral pathway

-Numerous paired, triangular extensions present along spinal cord, suspend and anchor spinal cord laterally to arachnoid and dura mater? -Thin strand of pia mater anchors conus medullaris to coccyx bone, extends within cauda equina? -Lies external to pia mater, composed of web of collagen and elastic fibers called arachnoid trabeculae? -Immediately deep to arachnoid mater, has CSF?

-Denticulate ligaments -Filum terminale -Arachnoid mater -Subarachnoid space

-Specific segment of skin innervated by a single spinal nerve, all spinal nerves except C1 innervate segment of skin? -Map is called what that follows segmental pattern along the body? -These are clinically important bc they can indicate?

-Dermatome -Dermatome map -Potential damage to one or more spinal nerves

-Uses chain of 2 motor neurons, originates in primary motor cortex of cerebral frontal lobe, derives name from presence of only ONE upper/lower motor neuron, has pyramidal-like shape of cell bodies? -Extends from frontal lobe of cerebral cortex through internal capsule/cerebral peduncles of brain, through corticospinal tract in spinal cord, synapses on lower motor neuron in anterior horn of spinal cord? -Extends from spinal cord through anterior root into spinal nerve to innervate target SM?

-Direct/pyramidal pathway -Axon of upper motor neuron -Axon of lower motor neuron

-Bc there are several diff spinal nerves in the terminal branch of the plexus, damage to a single segment of spinal cord/nerve? -Which parts of nerves do not form plexuses? -Anterior rami of spinal nerves T1-T11, located w/in intercostal space bw two adjacent ribs that do not form plexuses except for T1? -T12 is called this bc it arises inferior to ribs not bw two ribs?

-Does not result in complete loss of innervation to particular muscle or region of skin -most thoracic spinal nerves, S5-Co1 -Intercostal nerves -Subcostal nerve

-C5, innervates rhomboids, levator scapulae? -C5-C7, innervates serratus anterior? -C5-C7, innervates pectoralis major? -C8-T1, innervates pectoralis major/minor?

-Dorsal scapular -Long thoracic -Lateral pectoral -Medial pectoral

-Outermost layer of meninges, composed of dense irregular CT, only has one layer, ensheath the spinal nerve roots/merge w CT layer that surrounds spinal nerves? -Two spaces associated w dura mater? -Potential space internal to dura mater, bw arachnoid and dura? -Space external to the dura mater, houses adipose and areolar CT and BVs?

-Dura mater -Subdural space and epidural space -Subdural space -Epidural space

-Around muscle spindle are these which are innervated by alpha motor neurons named bc they have largest diameter axons? -Reflex initiated by muscle spindle proprioceptor and involves muscle reflexively contracting in response to stretching or muscle? -Muscle spindle stretched, sensation detected by neurons around intrafusal muscle fibers, transmit nerve signals to CNS where synapse w alpha motor neurons of muscles, AMN send nerve signals to extrafusal muscle fibers to contract muscle and resist stretch?

-Extrafusal muscle fibers -Stretch reflex -Process of stretch reflex

-L2-L4, main nerve of posterior division of lumbar plexus, innervates anterior thigh muscles, quadriceps femoris, sartorius, psoas, and iliacus, receives input from skin on anterior/inferomedial thigh and medial aspect? -L2-L4, main nerve of anterior division of lumbar plexus, extends through obturator foramen of os coxae to medial thigh, innervates medial thigh muscles, conducts sensory input from superomedial skin of thigh?

-Femoral nerve -Obturator nerve

1. Stimulus activates receptor 2. Nerve signal is propagated through sensory neurons to the spinal cord 3. Nerve signal is processed in the integration center by interneurons 4. Nerve signal is propagated by motor neuron to effector 5. Effector responds

-Five steps of a reflex/reflex arc

-Stretch reflex, golgi tendon reflex, withdrawal flexor reflex, and crossed-extensor reflex that can be initiated by proprioceptors or pain receptors? -Reflexes involving proprioceptors? -Proprioceptor that detects changes in stretch w/in a muscle, aka stretch receptor?

-Four spinal reflexes -Stretch reflexes and Golgi tendon reflexes -Muscle spindle

-Sensory receptors located throughout body distinct from special sense receptors limited to head? -General sense receptors subdivided into two categories: -Tactile receptors or proprioceptors? -Housed within the skin and mucous membranes that line body cavities, monitor characteristics of an object? -Located w/in joints, muscles, and tendons to detect stretch and pressure relative to position and movement of the skeleton and SM? -Located within walls of the viscera and blood vessels, detect changes to an organ or blood vessel?

-General sense receptors -Somatic sensory or somatosensory receptors -Tactile receptors -Proprioceptors -Visceral sensory receptors

-Reflex initiated by Golgi tendon organ proprioceptor? -Composed of sensory nerve ending w/in tendon or near muscle-tendon junction and detects change in tension/stretch in muscle tendon when muscle contracts? -Prevents muscles from stretching excessively? -Prevents muscles from doing the opposite, tensing or contracting excessively, polysynaptic reflex that results in muscle relaxation in response to increased tension @ Golgi tendon organ?

-Golgi tendon reflex -Golgi tendon organ -Stretch reflex -Golgi tendon reflex

-Within spinal cord, forms bar of gray matter connecting the left and right sides of posterior, lateral, and anterior horns, serves as communication route bw l/r sides of spinal cord? -An unusual gray matter region bc it primarily houses? -Small, internal channel that extends through center of gray commissure along entire length of spinal cord?

-Gray commissure -Unmyelinated axons -Central canal

-Composed of dendrites and cell bodies of neurons, functions as processing center? -Posterior horn gray matter subdivided into what two types of nuclei? -Site for synapses bw somatic sensory neurons that extend from somatic sensory receptors in skin, more posterior? -Location for synapses bw visceral sensory neurons that extend from visceral sensory receptors to interneurons within posterior horns of spinal cord, more anterior?

-Gray matter -Somatic sensory nuclei or visceral sensory nuclei based on type of sensory neurons that synapse there -Somatic sensory nuclei -Visceral sensory nuclei

-Reflexes may be one of three things: -Normal -Refers to reflex response that it diminished or absent, may indicate damage to segment of spinal cord or show muscle disease/damage @ neuromuscular junction? -Refers to an abnormally strong response, spinal reflex that may indicate damage in brain or spinal cord, if accompanied by: -A rhythmic oscillations bw flexion and extension, when muscle reflex is tested?

-Hypoactive reflex -Hyperactive reflex -Clonus

-L1, partial innervates some abdominal muscles, superior lateral gluteal region, inferior abdominal wall? -L1, partial innervates abdominal muscles, inferior abdominal wall, scrotum/labia majora? -L1, L2, innervates small area in anterior, superior thigh, scrotum/labia majora? -L2,L3, innervates anterolateral thigh?

-Iliohypogastric -Ilioinguinal -Genitofemoral -Lateral femoral cutaneous

-Upper motor neurons originate w/in brainstem nuclei + take complex route through brain to spinal cord that involves more than one upper motor neuron, helps control pattern of somatic motor activity by exciting/inhibiting lower motor neurons that innervate muscles? -Regulates/controls precise, discrete movements and tone in flexor muscles of limbs, gently laying baby in crib? -Pathway above has this that originate in red nucleus of midbrain?

-Indirect pathway -Lateral pathway -Rubrospinal tracts

-L5-S2, innervates gluteus maximus? -L4-S1, innervates gluteus medius, gluteus minimus, tensor fasciae latae? -S1-S3, innervates skin on posterior thigh? -S2-S4, innervates muscles of perineum, external anal sphincter, external urethral spincter, + skin on external genitalia?

-Inferior gluteal nerve -Superior gluteal nerve -Posterior femoral cutaneous nerve -Pudendal nerve

-Spinal cord is partitioned into what two areas? -Area centrally located, resembles an H, subdivided into components on each side of spinal cord: posterior horn, lateral horn, anterior horn, and a bar of this that connects l/r sides called gray commissure? -Both left and right posterior masses of gray matter, GM forming this due to presence of dendrites and cell bodies of interneurons, sensory neurons extend here? -Neurons located completely w/in CNS?

-Inner gray matter region and outer white matter region -Gray matter -Posterior horn -Interneurons

-Muscle spindle is composed of this surrounded by CT capsule, lack myofilaments and are contractile only @ distal regions? -Muscles above are innervated by both sensory neurons and these named bc gamma refers to motor neurons w small-diameter axons? -These stimulate contractile fibers at distal ends of intrafusal muscle fibers to contract which elongates inner portion of muscle spindle fiber causing it to be more sensitive to additional stretch?

-Intrafusal muscle fibers -Gamma motor neurons

-Name of each tract reflects what? -Sensory tracts usually begin with prefix what that indicates they originate from spinal cord? -Second part of name provides destination example of spinothalamic tract that? -Motor pathways begin with either this that indicates an origin in cerebral cortex or with the name of brainstem nucleus such as?

-Its origin and destination -Spino -extends from spinal cord to thalamus -Cortico, rubro

-Lateral to axillary artery, formed from anterior divisions of superior/middle trunks, C5-C7? -Five major these emerge from three cords: axillary nerve, median nerve, musculocutaneous nerve, radial nerve, and ulnar nerve?

-Lateral cord -Terminal Branches

-Direct pathways are housed w/in one of 2 pathways w/in spinal cord? -Composes 85% of direct path, innervates SM that control skilled movements in limbs such as playing a guitar, dribbling balls, typing? -Composes 15% of direct path, innervates axial SM?

-Lateral corticospinal tract and anterior corticospinal tract -Lateral corticospinal tract -anterior corticospinal tract

-Both l/r lateral masses of gray matter, located only w/in T1-L2 parts of spinal cord, not entire length of spinal cord, GM dues to presence of dendrites and cell bodies of autonomic motor neuron? -Collectively, thing above forms what that make up entire lateral horn on each side of spinal cord? -The axons of what extend to and innervate autonomic or visceral effectors? -These include body structures that are not controlled consciously or voluntarily like cardiac muscle, smooth muscle, or glands?

-Lateral horns -Autonomic motor nuclei -Autonomic motor neurons -Autonomic effectors

-Innervates skin of scalp superior and posterior to ear? -Innervates skin on superior part of chest and shoulder? -Innervates skin on anterior part of neck? -Important branch of cervical plexus, formed primarily from C4 nerve and axons from C3/C5, extends through thoracic cavity to innervate thoracic diaphragm, for breathing?

-Lesser occipital (C2) -Supraclavicular (C3,C4) -transverse cervical (C2/C3) -Phrenic nerve

-Last neuron of chain, cell body housed in anterior horn of spinal cord, axons exit spinal cord through anterior root and project to/innervate specific SM, always excites SM fibers to contract? -What are the two type of motor pathways? -Responsible for conscious control of SM activity? -Responsible for subconscious/reflexive control of SM?

-Lower motor neuron -Direct pathway and indirect pathway -Direct pathway -Indirect pathway

-C8-T1, Cutaneous innervation, medial side of arm? -C8-T1, Cutaneous innervation, medial side of forearm? -C5-C6, Innervates subclavius? -C5-C6, innervates supraspinatus, infraspinatus?

-Medial cutaneous nerve of arm -Medial cutaneous nerve of forearm -Nerve to subclavius -Suprascapular

-Regulates reflexive muscle tone and gross movements of the muscles of the head, neck, proximal parts of limbs, and trunk? -Originate from reticular formation in the midbrain, help control reflexive movements related to posture and maintaining balance? -Extends from superior + inferior colliculi in tectum of midbrain to help regulate reflexive positional changes of the upper limbs, eyes, head, and neck as consequence of visual/auditory stimuli? -Originate w/in vestibular nuclei of brainstem, nerve signals conducted regulate reflexive muscular activity helps maintain balance during sitting, standing, or walking?

-Medial pathway -Reticulospinal tracts -Tectospinal tracts -Vestibulospinal tracts

-Extends along midline of arm/forearm, deep to carpal tunnel of wrist, innervates most of anterior forearm muscles, thenar, lateral lumbricals -Receives sensory signals from palmar side of lateral 3 1/2 fingers -Formed from medial/lateral cords, anterior division of brachial plexus. C6-T1

-Median nerve

-Each spinal nerve forms the posterior root and anterior root with both sensory and motor neurons composing each spinal nerve, classified as? -When does the spinal cord end? -Where the spinal nerve roots of the lumbar, sacral, and coccygeal parts extend inferiorly from conus medullaris until part where they exit vertebral column called? -At L1 vertebra, represents inferior end of spinal cord and most superior portion of spinal roots forming cauda equina?

-Mixed nerve -Inferior border of L1 vertebra -Cauda equina -Conus medullaris

-Reflex can be classified by # of neurons participating in reflex: -Has only a sensory neuron and motor neuron, axon of sensory neuron synapses directly to motor neuron, one synapse bw neurons, simplest and most rapid? -Has one or more interneurons positioned bw sensory and motor neurons, reflex arc more complicated not as fast? -Reflex can be classified based on whether it involves one side of body: -Reflex which both receptor and effector organs are on same side of spinal cord?

-Monosynaptic reflex -Polysynaptic reflex -Ipsilateral reflex

-Descending pathways originate w/in brain and act to control effectors? -Motor neurons present in motor pathway, transmit signals from brain to body: -1st neuron in chain, cell body of this housed in cerebral cortex, cerebral nuclei, or nucleus in brainstem, axons synapse either directly upon lower neurons or upon interneurons that synapse to lower motor neurons? -Either excite or inhibit activity of lower motor neurons?

-Motor pathways -Upper motor neuron

-Intercostal nerves innervate what? -Helps form brachial plexus, but branch of it housed within 1st intercostal space? -Emerges from intervertebral foramen, innervates intercostal muscles of 2nd intercostal space, branch transmits sensory info from skin on axilla and medial surface of arm? -Follow costal grooves of ribs to innervate intercostal muscles and receive sensations from anterior/lateral chest wall?

-Much of torso wall and portions of upper limb -Anterior ramus of T1 -Anterior ramus of nerve T2 -Anterior rami of nerves T3-T6

-Innervates anterior arm muscles which flex humerus/forearm, receive sensory info from lateral surface of forearm? -Formed from lateral cord, anterior division of brachial plexus, C5-C7

-Musculocutaneous nerve

-Organ composed of cable-like bundle of axons enclosed within successive tissue wrappings? -Ensheathes the entire nerve? -Encloses fascicle/bundle of axons? -Electrically insulates each axon

-Nerve -Epineurium -Perineurium -Endoneurium

-L2-L4, extends knee when patellar ligament is tapped? -S1, plantar flexes ankle when calcaneal tendon is tapped? -L5, S1, flexes toes when plantar side of foot is briskly stroked?

-Patellar (knee-jerk) reflex -Ankle/achilles reflex -Plantar reflex

-Provides info to brain to identify object in hand even if eyes are closed, or positioning of arms? -Extends from somatosensory receptor into spinal cord via posterior root and ascends w/in posterior funiculus in spinal cord? -What are the specific fasciculus it ascends through? Makes a synapses with what secondary neurons in GM of medulla oblongata where?

-Posterior funiculus-medial lemniscal pathway -Axon of primary neuron in PFML -Fasciculus cuneatus/gracilis and nucleus cuneatus/gracilis

-Derived from white matter of posterior funiculus w/in spinal cord and medial lemniscus in brain, uses chain of 3 sensory neurons to communicated w brain about a specific stimulus? -Originates from tactile receptors housed in skin/mucous membranes or proprioceptors in joints, muscles, tendons? -Discriminative touch, precise pressure, and vibration sensations from tactile receptors of skin w conscious perception of skeleton and SM

-Posterior funiculus-medial lemniscal pathway -Where pathway above originates at 2 types of somatosensory receptors -information that this pathway provide to the brain/cerebral cortex

-What are the major 3 types of somatosensory pathways?

-Posterior funiculus-medial lemniscal pathway, anterolateral pathway, and spinocerebellar pathway

-Narrow groove on posterior surface of spinal cord? -Slightly wider groove on the anterior surface of spinal cord? -Four continuous subdivisions of spinal cord fro superior to inferior: -Which is continuous w medulla oblongata?

-Posterior median sulcus -anterior median fissure -Cervical part, then thoracic part, lumbar part, and sacral part

-Cell bodies of sensory neurons in posterior root are located external to spinal cord and form? -Contains motor neurons extend to effectors, like muscles or glands, relay nerve signals from spinal cord to control them, does not have a ganglion? -Motor neurons that compose the spinal nerves are? -Anterior roots lack what along its length?

-Posterior root ganglion -Anterior root -Multipolar neurons, both dendrites and cell bodies housed in spinal cord -Ganglions, only has axons of neurons

-Posterior root has sensory neurons extend from sensory receptors -Includes sensory neurons, relay nerve signals from somatic sensory receptors and visceral sensory neurons, relay nerve signals from visceral sensory receptors -Anterior root has motor neurons that extend to effectors, somatic motor neurons extend to autonomic motor neurons to effectors?

-Posterior versus anterior root of gray matter

1. Muscle contraction increases tension to tendons, detected by Golgi tendon organ 2. Muscle contraction stimulates sensory nerve signals that travel to CNS 3. Sensory neurons stimulate interneurons w/in spinal cord 4a. Interneurons inhibit alpha motor neurons to muscle, interneurons stimulate alpha neurons to antagonistic muscles 5a. Muscles relaxes and there is relief of tension on tendon, muscle contracts = reciprocal activation

-Process of Golgi tendon reflex

-Extends along posterior side of arm and radial side of forearm, innervates posterior arm/forearm, receives sensory nerve signals from posterior arm and forearm surface of dorsolateral side of hand? -Formed from posterior cord, posterior division, C5-T1

-Radial nerve

-Additional rami, associated w spinal nerves, contain axons associated w autonomic nervous system? -Each set of rami communicantes extends bw spinal serve and a spherical structure called? -Ganglia are interconnected and form beaded necklace-like structure called?

-Rami communicantes -Sympathetic trunk ganglion -Sympathetic trunk

-Rapid, preprogrammed, involuntary responses of muscles or glands to a stimulus? -Stimulus is required to initiate reflex, rapid response requires few neurons involved w synaptic delay, preprogrammed response occurs same way every time, involuntary response requires no conscious intent/pre awareness of reflex activity? -Includes sensory receptor, an effector, and neural wiring between two?

-Reflexes -Properties of reflexes -Reflex arc

-L/R formed from anterior rami of spinal nerves L4-S4, located immediately inferior to lumbar plexuses, innervate gluteal region, pelvis, perineum, posterior thigh, and almost all of leg and foot? -Lumbar and sacral plexuses together considered as? -Nerves in anterior division of sacral tend to innervate muscles that? -Nerves in posterior division of sacral tend to innervate muscles that?

-Sacral plexuses -Lumbosacral plexus -Flex/plantar flex parts of lower limb -Extend/dorsiflex part of lower limb

-L4-S3, known as ischiadic nerve, largest and longest nerve in the body, formed from ant/post divisions, projects from pelvis through greater sciatic notch of os coxae, extends into posterior region of thigh, composed of a tibial and common fibular division? -L4-S3, formed from anterior division of sciatic nerve, innervates hamstrings posteriorly, extends w/in posterior compartment of leg, innervates plantar flexor/toe flexors -Splits into lateral/medial plantar nerves innervates muscles of the foot and input from SOLE of foot?

-Sciatic nerve -Tibial nerve

-Second-order neuron, an interneuron extends from primary neuron to either tertiary neuron or cerebellum? -Third-order neuron, an interneuron extends from secondary neuron to cerebrum/primary somatosensory cortex of parietal lobe?

-Secondary neuron -Tertiary neuron

-Includes sensory neurons that relay sensory input to the brain, called this bc nerve signals are relayed from sensory receptor superiorly to brain? -Include series of motor neurons relay motor output from brain, called this bc nerve signals relayed from brain inferiorly to body's muscles and glands? -Gen characteristics of conduction pathways: -All pathways composed of paired tracts, pathway on one side of CNS has matching tract on other side of CNS? -Most pathways are made of a series of two or three of these that form the pathway?

-Sensory/ascending pathways -Motor/descending pathways -Paired tracts -Composed of two or more neurons

-Individual tracts can be: -These that conduct nerve signals from the spinal cord to the brain? -These that conduct nerve signals from the brain to the spinal cord? -Sensory input is relayed to the brain w/in each? -But motor output from the brain is relayed only within?

-Sensory/ascending tracts -Motor/descending tracts -Funiculus -Lateral/anterior funiculi

-Sensory pathways have two categories depending on type of general sensory receptor involved: -Process stimuli received from somatosensory receptors? -Process stimuli received from visceral sensory receptors? -Three neurons in sensory pathways that transmit nerve signals from sensory receptors to brain: -First-order neuron, 1st neuron in chain of neurons, extends from sensory receptor to the CNS, where it synapses w a secondary neuron?

-Somatosensory pathways -Viscerosensory pathways -Primary neuron

-Cylindrical NS structure that extends through the vertebral column to inferior border of L1 vertebra? -Superior end of spinal cord continuous w medulla oblongata and its inferior end narrows to form this? -What are the two longitudinal depressions that extend the full length of the spinal cord?

-Spinal cord -Conus medullaris -Posterior median sulcus and anterior median fissure

-Provide essential structural and functional link bw brain and torso and limbs of body, in which sensory input and motor output occur in neuron pathways -Spinal reflexes, NS response that do not require involvement of brain, have spinal cord as integration center, these give quickest reactions to stimulus?

-Spinal cord and attached spinal nerves functions

-CT membranes that protect and encapsulate the spinal cord within the vertebral canal? -From innermost to outermost, the spinal cord meninges are? -Directly adheres to external surface of spinal cord, delicate, innermost, elastic and collagen fibers? -Pia mater extensions form what two structures, that help stabilize the spinal cord within the vertebral canal?

-Spinal cord meninges -Pia mater, arachnoid mater, and dura mater -Pia mater -Denticulate ligaments and filum terminale

-Five different ways of classifying a reflex: -Reflex may be identified by specific area of CNS (integration center) that serves as processing site, 1st involves spinal cord, second involves brain? -Classification determined by type of effector that is stimulated by motor neurons involved in reflex, 1st involves SM as effector, 2nd involves cardiac/smooth muscle or gland as effector?

-Spinal reflex or cranial reflex -Somatic reflex or visceral reflex

-C5-C6, subscapularis, teres major? -C6-C8, latissimus dorsi? -L/R formed from anterior rami of spinal nerves L1-L4, located lateral to L1-L4 vertebrae, innervates inferior abdominal wall, anterior thigh, medial thigh, and skin of medial leg? -Divided into what two regions?

-Subscapular nerves -Thoracodorsal nerve to latissimus dorsi -Lumbar plexuses -Anterior and Posterior regions

-By 6th weak of development, horizontal groove called what forms in lateral walls of central canal that is the dividing point in neural tube? -Thing above divides as two regions become evident: -Lie anterior to sulcus limitans, develop into anterior/lateral horns and anterior part of gray commissure? -Lie posterior to sulcus limitans, by 9th week, develop into posterior horns and posterior part of gray commissure?

-Sulcus limitans -Basal plates -Alar plates

-Nerves C5/C6 unite to form? -Nerve C7 forms? -Nerves C8 and T1 unite to form?

-Superior trunk -Middle trunk -Inferior trunk

-Type of stretch reflex, which is a spinal reflex, somatic reflex, monosynaptic, and ipsilateral, and innate? -When sensory nerve signals reach spinal cord, some sensory axons synapse w interneurons that synapse w alpha motor neurons that inhibit antagonistic muscle contraction? -Reciprocal inhibition is what bc it uses interneuron w/in circuit?

-Triceps reflex -Reciprocal inhibition -Polysynaptic

-Descends on medial side of arm, extends posterior to medial epicondyle of humerus, extends along ulnar side of forearm, innervates anterior forearm muscles, intrinsic hand muscles, receives input from dorsal/palmar aspects of pinky/ring finger? -Formed from medial cord, anterior division of brachial plexus, C8-T1

-Ulnar nerve

-Bony framework houses spinal cord, 26 stacked and intervertebral discs bw, allows movement of torso? -All stack vertebral foramina collectively form this houses the spinal cord and cauda equina? -Where each spinal nerves exits through vertebral column, lateral opening bw two adjacent stacked vertebrae?

-Vertebral column -Vertebral canal -Intervertebral foramen

-Composed of myelinated axons, functions in relaying nerve signals, external to gray matter in spinal cord and has 3 distinct regions? -Each region of white matter in the spinal cord? -White matter lies bw posterior gray horns on the posterior side of cord/posterior median sulcus? -White matter on each lateral side of spinal cord?

-White matter -Funiculus -Posterior funiculus -Lateral funiculus

-Involves muscles contracting to withdraw body part away from painful stimulus, involves pain receptors called nociceptors? -Is initiated by painful stimulus that initiates nerve signal that is transmitted by sensory neuron to spinal cord and interneurons receive sensory nerve signal + stimulate motor neurons to flexor muscles, flexor muscles contract in response?

-Withdrawal/flexor reflex