AP Notes, Outlines, Study Guides, Vocabulary, Practice Exams and more!

Anatomy and Physiology: Chapter 13 - PNS Flashcards

Terms : Hide Images
5328200255Peripheral nervous system (PNS)Portion of the nervous system consisting of nerve, ganglia, sensory receptors, and motor endings that lie outside the brain and spinal chord0
5328200256Sensory (afferent) nervesNerves that contain processes of sensory neurons and carry impulses to the CNS1
5328200257Sensory receptorsA cell or part of a cell specialized to respond to a stimulus2
5328200258StimulusAn excitant; a change in the environment that evokes a response3
5328200259SensationAwareness of the stimulus4
5328200260PerceptionInterpretation of the meaning of the stimulus5
5328200261MechanoreceptorsRespond to mechanical force such as touch, pressure (including blood pressure), vibration, and stretch6
5328200262ThermoreceptorsRespond to temperature changes7
5328200263PhotoreceptorsSuch as those of the retina of the eye, respond to light8
5328200264ChemoreceptorsRespond to chemicals in solutions (molecules smelled or tasted, or changes in blood or interstitial fluid chemistry)9
5328200265Nociceptors(Noci = harm) Respond to potentially damaging stimuli that result in pain ex: searing heat, extreme cold, excessive pressure, and inflammatory chemicals are all interpreted as painful; these signals stimulate subtypes of thermoreceptors, mechanoreceptors, and chemoreceptors10
5328200266ExteroceptorsAre sensitive to stimuli arising outside the body (extra = outside); they are near or at the body surface; includes touch, pressure, pain, and temperature receptors in the skin and most receptors of the special senses (vision, hearing, equilibrium, smell, and taste)11
5328200267InteroceptorsAlso called visceroceptors, respond to stimuli within the body (intro = inside), such as from the internal viscera and blood vessels; monitor a variety of stimuli includes chemical changes, tissue stretch and temperature; their activity causes us to feel pain, discomfort, hunger, or thirst; unaware of the workings12
5328200268ProprioceptorsOccur in skeletal muscles, tendons, ligaments, joints, and in connective tissue covering the bones and muscles; advises the brain of our body movement (propria = one's own) by monitoring how much the organs containing these receptors are stretched13
5328200269Special senseVision, hearing, equilibrium, smell, and taste14
5328200270Nonencapsulated (free) nerve endingsParticularly abundant in epithelial and connective tissue; most sensory nerve fibers are non-myelinated, c-fibers, and their distal endings usually have small knob-like swellings; respond chiefly to temperature changes and painful stimuli, some respond to muscle movement and pressure (tactile and hair follicle)15
5328200271Tactile (Merkel) discsLie deepest in the dermal layer of the epidermis, function as light touch receptors; exteroceptors and mechanoreceptors, slowly adapting16
5328200272Hair follicle receptorsFree nerve ending that wrap basket-like around hair follicles, are light touch receptors that detect bending of hairs; exteroceptors and mechanoreceptors, rapidly adapting17
5328200273Encapsulating nerve endingsConsists of one or more nerve fiber terminals of sensory neurons enclosed in a connective tissue capsule; virtually all mechanoreceptors18
5328200274Tactile (Meissner's) corpusclesSmall receptors in which a few spiraling sensory terminals are surrounded by Schwann cells and then by a thin leg-shaped connective tissue capsule; found beneath the epidermis in the dermal papillae, numerous in hairless skin areas (nipples, fingertips, and soles of the feet); exteroceptors and mechanoreceptors, rapidly adapting19
5328200275Lamellar (Pacinian) corpusclesScattered in the deep in the dermis and the subcutaneous tissue underlying the skin; larges corpuscle receptors, single dendrite surrounded by a capsule of collagen fibers; exteroceptors, interoceptors, and proprioceptors; mechanoreceptors, are rapidly adapting20
5328200276Bulbous corpuscles (Ruffini endings)Lie in the dermis, subcutaneous tissue, and joint capsules; contain a spray of endings enclosed by a flattened capsule exteroceptors and proprioceptor; mechanoreceptors, slowly or non-adapting21
5328200277Muscle spindlesSpindle-shaped proprioceptors founding the skeletal muscles (particularly extremities); muscle spindles detect muscle stretch and initiate a reflex that resists the stretch; proprioceptors and mechanoreceptors22
5328200278Tendon organsAre proprioceptors located in the tendons, close to the junction between the skeletal muscle and the tendon; small bundles of a tendon enclosed in a layered capsule; proprioceptors and mechanoreceptors23
5328200279Joint kinesthetic receptorsMonitor stretch in the articular capsules that enclosed synovial joint; proprioceptors and mechanoreceptors24
5328200280Somatosensory systemThe part of sensory system dealing with reception in the body wall and limbs; receives input from from exteroceptors, proprioceptors, and interoceptors25
5328200281Receptor levelSensory reception and trasmission to CNS26
5328200282TransductionThe conversion of the energy of a stimulus into an electrical event (graded potential)27
5328200283Generator potenitalThe graded potential generates action potential in a sensory neuron28
5328200284Receptor potentialA graded potential that occurs at a sensory receptor membrane29
5328200285Adaptation(1) A change in any in structure or response to suit a new environment; (2) decline in the transmission of a sensory nerve when a receptor is stimulated continuously and at a constant stimulus strength30
5328200286Phasic receptorsFast adapting, often giving bursts of impulses at the beginning and at the end of the stimulus; report changes in the internal or external environment (lamellar and tactile corpuscles)31
5328200287Tonic receptorsProvide a sustained response with little or no adaptation; includes nociceptors and most proprioceptors because of the protective importance of their information32
5328200288Circuit levelProcessing in ascending pathways; delivers impulses to the appropriate region of the cerebral cortex for localization and perception of stimulus33
5328200289Perceptual levelProcessing in cortical sensory centers; sensory input is interpreted in the cerebral cortex34
5328200290ProjectionEletrically stimulating a particular spot in the visual cortex causes you to "see" light in a particular space35
5328200291Perceptual deceptionThe ability to detect that a stimulus has occurred; the simplest level of perception; inputs from several receptors must be summed for perpetual detection to occur36
5328200292Magnitude estimationThe ability to detect how intense the stimulus is; perceived intensity increases because as stimulus intensity increases because of frequency coding37
5328200293Spatial discriminationAllows us to identify the cite or pattern of stimulation38
5328200294Two-point discriminationA test to study how close together 2 points on the skin can be and still be perceived as 2 points rather than 139
5328200295Feature abstractionIs the mechanism by which a neuron or circuit is tuned to one feature, or property, of a stimulus in preference to others; enables us to identify more complex aspects of a sensation40
5328200296Quality discriminationIs the ability to differentiate the submodalities of a particular sensation; each sensory modality has several qualities41
5328200297Pattern recognitionThe ability to take in the scene around us and recognize a familiar pattern an un familiar one, or one that has special significance for us42
5328200298HyperalgesiaGreater than normal sensitivity to pain43
5328200299Referred painWhich pain stimuli arising from one part of the body are perceived as coming from another part44
5328200300NerveA chord like organ that is part of the peripheral e=nervous system45
5328200301EndoneuriumA delicate layers of loose connective tissue that also enclose the fiber's associated Schwann cells46
5328200302PerineuriumCoarser connective tissue wrapping binds a group of fascicles47
5328200303FasciclesBundles of axons48
5328200304EpineuriumCloses the fascicles to form the nerve49
5328200305Mixed nervesContain both sensory and motor fibers and transmit impulses both to and from the CNS50
5328200306Motor (efferent) nervesCarry impulses only away from the CNS51
5328200307GangliaCollections of neuron cell bodies associated with nerves of the PNS52
5328200308CNS axonsThese axons never regenerate from injury, damage to the brain or spinal chord are viewed irreversible; oligodendrocytes actively suppress axon regeneration, astrocytes block the growth of a new axon with scar tissue53
5328200309PNS axonsCan regenerate successfully if they are crushed or cut; macrophages clean out the dead axons distal to the injury, axon filaments grow through a regeneration tube, and myelin sheath forms54
5328200310Cranial nervesThe 12 nerve pairs that are associated to the brain55
5328200311Olfactory(I) The tiny sensory nerves (filaments) of smell which run from the nasal mucosa to synapse with olfactory bulbs; Sensory56
5328200312Optic(II) Fibers arise from retina of the eye, passes through optic canal of orbit, vision;sensory57
5328200313Oculomotor(III) Fibers extend from ventral midbrain (near its junction with the pons) and pass through bony orbit; motor; "eye mover"58
5328200314Trochlear(IV) Fibers emerge from the dorsal midbrain and coarse ventrally around midbrain to enter orbit through superior orbital fissure; motor; "pulley"59
5328200315Trigeminal(V) Largest cranial nerves, fibers extend from pons to face and from 3 divisions: ophthalmic, maxillary, and mandibular; sensory60
5328200316Abducens(VI) This nerve controls the extrinsic eye muscle that abuts the eye and turns it laterally; motor61
5328200317Facial nerves(VII) A large never that innervates muscles of facial expressions; both (taste)62
5328200318Vestibulocochlear(VIII) Both sensory and motor (hearing); this nerve is found in the inner ear63
5328200319Glossopharyngeal(IX) Means tongue and pharynx; both (taste)64
5328200320Vagus(X) Wander or vagabond, its the only cranial nerve to extend beyond the head and neck to the thorax and the abdomen65
5328200321Accessory(XI) Considered and accessory pat of the vagus nerve, they from the rootlets that emerge from the spinal chord, not the brain stem; both66
5328200322Hypoglossal(XII) Meaner under the tongue and it runs inferior to the tongue and innervates the tongue muscles; roots from the medulla and exits the skull; both allow tongue movements67
5328200323RootletsAttach along the length of the corresponding spinal chord segment68
5328200324Ventral rootContain motor (efferent) fibers that arise from ventral horn motor neurons and extend to an and innervate the skeletal muscles69
5328200325Dorsal rootContain sensory (afferent) fibers that arise from sensory neurons in the dorsal root ganglia and conduct impulses from peripheral receptors to the spinal chord70
5328200326RamusBranch71
5328200327Nerve plexusInterlacing nerve networks that occur in the cervical, brachial, lumbar, and sacral regions and primarily serve the limbs72
5328200328Cervical plexusC1 - C573
5328200329Upper limb plexusC4 - T174
5328200330Lumbar plexusL1 - L575
5328200331Sacral plexusL4 - Co176
5328200332DermatomeAn area of skin innervated by the cutaneous branches of a single spinal nerve77
5328200333Hilton's lawAny nerve serving a muscle that produces movement at a joint also innervates a joint and the skin over the joint78
5328200334Motor endingsThe PNS elements that activate effectors by releasing neurotransmitters79
5328200335Segmental levelLowest level of the motor hierarchy, it consists of reflexes and spinal chord circuits that control automatic movements; contains central pattern generations (CPG)80
5328200336Central pattern generationsCircuits that control locomotion and other specific oftrepated motor activities; consists of networks of oscillating inhibitory and excitatory neurons, which set crude rhythms and alternating patterns of movement81
5328200337Projection levelConsists of neurons actin through the direct and indirect motor pathway; middle level of the motor hierarchy; conveys instructions to the spinal chord motor neurons and sends a copy of that information to higher levels82
5328200338Precommand levelHighest level of the motor hierarchy; located in the brain stem and the cerebellum; it regulates motor activity, precisely start or stop movements, coordinate movements with posture, block unwanted movements, and monitor muscle tone83
5328200339Reflex arc 5 components1. Receptor 2. Sensory input 3. Integration center 4. Motor neuron 5. effector84
5328200340ReceptorSite of stimulus action85
5328200341Sensory neuronTransmits afferent impulses to the CNS86
5328200342Integration centerMay be a single synapse between a sensory neuron and a motor neuron (monosynaptic); more complex reflex arcs involve multiple synapses with chains of interneurons (polysynaptic)87
5328200343Motor neuronConducts efferent impulses from the integration center to the effector organ88
5328200344EffectorMuscle fiber or gland cell that responds to the efferent impulses (by contracting or secreting)89

Need Help?

We hope your visit has been a productive one. If you're having any problems, or would like to give some feedback, we'd love to hear from you.

For general help, questions, and suggestions, try our dedicated support forums.

If you need to contact the Course-Notes.Org web experience team, please use our contact form.

Need Notes?

While we strive to provide the most comprehensive notes for as many high school textbooks as possible, there are certainly going to be some that we miss. Drop us a note and let us know which textbooks you need. Be sure to include which edition of the textbook you are using! If we see enough demand, we'll do whatever we can to get those notes up on the site for you!