PSL431 Exam 2 Study Guide
PSL431 Exam 2 Study Guide PSL431
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This 16 page Study Guide was uploaded by Megan Penzkofer on Friday February 13, 2015. The Study Guide belongs to PSL431 at Michigan State University taught by Dr. Leinninger in Fall. Since its upload, it has received 179 views. For similar materials see Human Physiology 1 in Physiology at Michigan State University.
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Date Created: 02/13/15
PSL431 Exam 2 Study Guide 0 one motor axon terminal and one skeletal muscle ber 0 Motor neuron cell bodies originate from brainstem or ventral horn of spinal cord the axons may be extremely long as they project directly to muscle 0 Utilizes acetylcholine always excitatory Nicotinic Acetylcholine receptors in muscle are activated by ACh when neurotransmitter is released 0 Axons split into multiple synaptic which meet with the muscle cell at the o Voltagegated Ca channels in boutons are opened when AP from neuron reaches end of axon increase cytosolic Ca and promotes vesicle release exocytosis of ACh Vesicle release is prevented by Mon terminal of r motor neuron l Aeiionpolaniial propagation in FI IEiil ilnEUf lili39lfmlin sheath a y p j TIErrnimElll Hutton Voltageug ted Veslcleol Ha ehnnel aneurlcvlmllne Emmygated matchannnl Plasma membrane ction potential G1 muscle ber u g pmpargalion WV H immuselefiber gt 7 a gar V H tw all quot atulem llnaahmH J if gt r l t 7 if a i l m lmuhu nngnlndl rmmm m al mfg wispWile when Willie mlmclila EIIEEI39IEI39IIIE within muscle liner 0 2 ACh molecules bind to ACh receptor on muscle cell and lets in a small amount of Na and lets out a small amount of K causing membrane to depola by or rize Called ACh binding may be prevented snake venom and as well as antibodies produced by a patient with Much stronger than EPSP because there are many boutons releasing a lot of ACh and End Plate is large and can contain a LOT of nACh receptors Each channel conducts a xed amount of current every time it opens multiple nACh channels can open simultaneously and sum their currents Rate of opening of nACh receptors is dependent on ACh diffusion across synaptic cleft diffusion is variable but there is so much ACh being released that it often occurs very quickly o EPP activates Voltagegated Na channels in muscle which then instigate AP Na channels can be blocked by pufferfish toxin 0 Not all ACh is bound to receptors some diffuses some is hydrolysed Therefore EPP falls slowly 40 HIGH ACh m cleft Unbound ACh 0 is gone channels close as ACh dissociates 60 and egrades Time 0 ACh may be degraded by enzyme important for terminating signal and allowing relaxation Acetylcholinesterase may be VISION destroyed by and causes increased muscle contraction and asphyxiation because diaphragm cannot be relaxed Structure of the eye Biliary may IIL Arrang Front retina ml i 121 E A lllI39 l r r 7 V lirl39IPE39IV39I39H I39EW I I linuiiiiiiiliuib Cone Find Photureeeptor cells Fibers at Ganglion Amaerine the optic cell cell nerve I Horizontal cell Bipular cell Retina llllJlllIllI 21 quot gel to retina the a 1t and lines the Pigment layer Choroid layer Sclera of retina 0 Vision is dependent on light reaching photoreceptor cells primary sensory neurons of the visual system 0 Axons of neurons in eye are unmyelinated to allow more light through but cell bodies of and transmission to photoreceptor cells get in the wayquot and light and cannot be perfect Why Fovea is so clear there are no cell bodies in the way of the photoreceptors 0 quotBlind Spotquot occurs right over top of optic nerve because there are no photoreceptors in that region 0 Properties of photoreceptors 0 Made up of three segments Outer Segment at outer surface of retina contains stacked discs of membranes lled with membranespanning proteins 1 bound to lightabsorbing molecules 1 all types of photoreceptors have the same retinal but different types of opsins that each bind retinal in a slightly different way Inner Segment inside retina Acts as the cell body Releases Glutamate to bipolar cells to relay Synaptic Terminal visual information Rods Cones Specialized For Night Vision Day Vision Light Sensitivity High Photopigment Rhodopsin allows us to see in gray Red Blue and Green conl contain unique pigments different parts of visual lig spectrum allows for colt vision Ampli cation High many rods synapse on to one bipolar neuron allowing for more sensitive detection of dim light Lower Timing of Response to Light Slower Faster May detect quick ickering ln Fovea NO YES Acuity sharpness of vision Low High transmission of signals in nerves in response to light NOT APquot conformational changes 1 Cisretinal is transformed into transretinal This causes Opsin to undergo 2 Opsin is essentially a Gprotein activated by light or subunit is activated by conformational change 3 Transducin activates effector protein PDE which degrades a secondary messenger called 4 cGMP is the ligand to cGMPgated Na channels In the dark channels are OPEN more cGMP is present In the light channels are CLOSED less cGMP is present 0 Causes hyperpolarization 5 Hyperpolarization prevents opening of Ca channels and therefore prevents vesicular Glutamate release to bipolar cells Nerve Signal passes from photoreceptor cells l bipolar cells l ganglion cells 0 Graded potentials responsible for transmission along photoreceptor cells and bipolar cells 0 Each photoreceptor makes synapse with two bipolar cell types detects light shining onto center of photoreceptor detects light shining around photoreceptor Causes cells to convey contrast rather than absolute intensity 0 Ganglion cells are cell bodies whose axons make up the Optic Nerve and re AP that gets sent to the brain occurs when there is some issue with the cone cells in the eyes 0 color blindness only express two types of cone cells usually missing green cones deuteranopia or red cones protanopia o color blindness express all types of cone cells but have either less sensitivity in green cones deuteranomaly or red cones protoanomaly Retinas can be divided at imaginary midline through fovea o retinal half close to nose RlGH39II39 o ear retinal half close FieldW Field to Nasal and Pathway from Eye to Brain together tlt Font Color 0 Left Optic Nerves from 1 Eye enter brain and a O ngh IPL39l39i ll retinal a n d u quot I 39 Some Axon Cross at the 0 tie Fibers fron Chliasml I p in at the Axon Terminals Synapse ante the Lateral Geniculate Nucleus LGM in the Thelamus Va gu 3 I r ii vquot quot ll P I W J t V 39 7 a l ILGN Neurons l quot send Axons to the Visual Cortex in Occipital Lobe o processes messages from each eye in adjacent columns o process color info 0 detect shapes and movement 0 Combine visual stimuli from both eyes Important for depth perception and binocular vision HEARING Sound is measured in waves 0 Frequency determines pitch 0 Amplitude determines loudness Structure of ear Pmna m Tympani Mutant53w I alien m mnr quotHES grimll E Ema EeImtclreular I Ijenrtllmml l A a W 1 53 1395 Irulers lizlulallr U Imla apparatus V illf lilll WWW I V 39iaiali wmjnw Veslibulucrmzhlear nerve 39C chlea Fianna window Eustamsan u tube Tphargfm o folds of cartilage and skin that receives sound waves and focuses them into the ear canal eardrum is stretched across entrance to middle ear o Bordered on both sides by air can cause bulging and pain when pressure outside is different than pressure inside 0 Middle ear is connected to pharynx with which may be opened by yawning chewing etc and can equalize pressure 0 Middle ear contains the ear bones 1 sound wave is converted to mechanical movement as vibrations from the tympanic membrane move through the bones o attached to tympanic membrane 0 o attached to oval window of cochlea 0 Inner ear s main structure is the 0 Contains three bone covered coils with three uid lled compartments 7 quot a a latearlibnnlar mmbraln Eurahlleas w HEIlE l l l l Basilar membrane rij39rganl all Eurti with hairs of Minibus Imus hair malls displaytad in Lauriace Etapae at nial window Ta i rial membrane L J 39 Emil media cochlea r dun1 39 Elfym i V r 39lJeslilbularmamhrane A Teelmiei membranes Simian u ti uli 397 Hound window a Scale lE Eternal Middle Ear quotI au i lwy cavity mg la MEWS rm at Emmi emblem Tympani membrane duct a Grass anatomy of middle ear and mhlea V a ilar mtl i cochlea partly UE39IE jl d Ru39 39mw quotENE membrane E l lemmnii 39 o Fluid moves through the cochlea in response to vibration of Tympanic Membrane Sound energy may move all the way around cochlea past the the point where and connect OR take a shortcut through vestibular membrane and into Movement of scala media movement of Organ of Corti movement of Basilar membrane sound perception The distance a sound travels down the basilar membrane determines the frequency that is detected low frequency is detected near helicotrema where the membrane is wide and oppy and high frequency is detected near tail where the membrane is narrow and stiff o rides on top of which contains sound receptive neurons Hair cells three rows of which amplify motion of basilar membrane and enhance stimulation of inner hair cells and one row of g which act to convey sound to the brain make contact with Membrane displacement sensation of sound 0 Hair Cells consist of multiple hair bers which are connected by cords that hold the stereociia together and manage the openingclosing of mechanically gated ion channels Endolymph ECF has a higher concentration of K than the cell opposite concentration gradient of normal cell opening of mechanicallygated ion channels by stretching of tip links causes in ux of K lnereaeee rate all aetien petentiale Tip lnlra e39itreteh and epen ehannele when atereeeia tine teward talleel memhe r HE entera hair eel clearliarizee Dplarizatien eeen veritaeeeatetl Ee f ehannele 39 C324 EaEquot entry eaueee greater reaaae at neuretrenemitter lr39lere neare tranemitter lEErElE lie hgher ESE at aetien eatential NE E ii i l patentiala Tip linlea aileeleen anti elee ehannela when atereeeilia and away frem talleel member hie is en39ere heir eell hyperpielariaee hl neura lranemiher ie reieaadi He aetien etentiala eeeur Each hair cell makes synapse with multiple whose axons make up the which enters the brain o Auditory information moves from auditory nerve to brainstem to inferior colliculus to thalamus to auditory cortex on the temporal lobe bers from each ear go to both sides of the brain 0 when sound waves cannot be conducted into inner ear ex too much earwax blocks sound waves from reaching tympatic membrane 0 damage to inner ear prevents perception of sound ex Loss of hair cells loss of hearing tinnitus ringing NER VOUS SYSTEM STRUCTURE o CNS made up of brain and spinal cord 0 Encased in bony protection skull and vertebrae o regions made of neuronal cell bodies 0 regions made of axons whitequot because they are covered in Myelin Make up 90 of the CNS Use chemical signals to communicate with one another and with neurons Also help to maintain homeostatic ECF conditions and can modulate synaptic function Copyright r The MoGrawHill Companies Inc Permission required ilor reproduction or display Frontal lobe Parietal lobe Forebraln Emblle Dilenoephalon Corpus celloser Oooiplllal lobe Temporal lobe Brailnstenr Poms Medu a Cerebellum I oblorrgata rimquot FE 7 Spi rial cord responsible for sensation perception reasoning learning memory skilled movement interconnects left and right hemispheres of cerebral COFtEX Subcortical Nuclei o acts as a relay stationquot in sensory pathways control center for homeostasis connected to pituitary gland Necessary to maintain balance and to coordinate voluntary muscle activity Origin of cranial nerves control center for visceral systems receives synaptic input from spinal cord activates cerebral cortex regulates muscle re exes thalamus hippocampus temporal lobe amygdala hypothalamus olfactory bulb Responsible for emotion survival behaviors sexual behaviors motivation through reward and punishment centers and learning controls ability to focus and direct attention Bones that make up the spine 0 side faces front of body where the quotbodyquot of the vertebrae are 0 side faces back of body where spinous protrusions are 0 Each vertebral bone is named and numbered Four regions of spinal cmumn Cervica7 vertebrae 8 nerves Thoracic 12 vertebrae 12 nerves Lumbar5 vertebrae 5 nerves 0 Spinal cord ends around L2 vertebra bottom of spinal column is a horsetail of spinal nerves Lumbar punctures are therefore performed between L3 and L4 vertebrae to avoid nicking the spinal cord SacraLarge sacrum bone 5 nerves 0 Spinal cord is contained within vertebrae Gray matter Vehtral Dorsal mm If mm xii Dorsal While matter I mm 39 H f f r v lDorsal 39 gang on Spinal C fd aha than Spinal H m Ventral nerve 1x 7 root i P Vertebra o contain cell bodies of gobetween for afferent and efferent neurons connects peripheral information to peripheral responses and contain cell bodies of motor neurons 0 Spinal nerves pass through holes between vertebral bones Connect CNS to other body structures made up of clusters of nerves and neuronal cell bodies Located outside of the brain and spinal cord 0 Carry AP from peripheral sensory receptors to CNS Sensory Special axons detect particular stimuli Enter spinal cord via sensory neuron cell bodies lie in the Two types SAN which innervates body s framework and VAN which innervates internal organs 0 Carry AP from CNS to peripheral tissues Motor Cause muscle excitation or relaxation Leave spinal cord via ventral roots Two types SEN and VEN o Bundles of nerve axons form grossly visible bers which often contain a mixture of afferent and efferent nerve bers A spinal nerves are mixed nerves and so are most named peripheral nerves 0 Cranial Nerves made up of afferent and efferent nerves that enter the brain instead of the spinal cord I Olfactory smell ll Optic sight III Ocuomotor eye muscles IV Fochear eye muscle V Figeminal Sensory nerve of face sinuses teeth Chewing muscles VI Abducent eye muscle VII Facial Face muscles taste front part of tongue VIII Vestibuocochear Hearing IX Gossopharyngeal taste back pa rt of tongue X Vagus visceral organ control and sensation XI Accessory neck muscles XII Hypogossal tongue muscles REFLEXES General Types 0 exion or withdraw from dangerouspainful stimulus o Stretch of muscle causes contraction of the same muscle ex knee jerk reaction Also where forceful contraction of a muscle causes sudden relaxation ex arm wrestling 0 light causes pupil constriction o sweating and shivering in response to heat and cold respectively 0 Begin with stimulation of sensory receptors which can convert stimulus into an action potential and transmit the information to the brain Receptors are de ned by their or the stimulus to which they are most sensitive o stimulated by heat or cold 0 stimulated by noxious and potentially tissuedamaging stimulus Polymodal can be activated by multiple types of stimulus Bare nerve endings with two different types of bers 0 A 6 myelinated axons fast sharp pain 0 C unmyelinated axons slow dull pain Stimulus energy causes cation channels to open depolarizing to threshold and stimulating AP THRESHOLD IS VERY HIGH Increased damage increased AP ring more pain 0 stimulated by touch pressure vibration stretching Varying degrees of stimulus needed to depolarize to threshold 1 0W Touch receptors rapid utter vibration lateral stretch mediumlow Pressure receptors 1 mediumhigh 0 Special Sensesquot light odor sound taste Re ex occurs in ve basic steps Sensory receptor receives stimulus Receptor produces AP which moves to CNS through sensory neurons Interneurons in CNS receive AP and neurotransmitters from sensory neurons CNS transfers AP to motor neurons and out to peripheral nerves Effector organ responds U39lbUUNI I on same side of body as stimulus often exeswithdraws in response to stimulus on opposite side of body as stimulus often extends to balance and account for exion of ipsilateral muscles Sensory neurons can make multiple interneuron contacts and subsequently cause multiple motor reactions coordination of muscle responses is often necessary for appropriate re ex Sensory receptors often quotadaptquot they stop ring AP even if the stimulus persists o Adapt rapidly Useful when it is only necessary to relay information to the brain if the stimulus changes ex the sensation of having clothes on your body Only re AP when stimulus begins and ends 0 Adapt slowly Important when it is necessary to maintain information about a stimulus over time ex the sensation of degrees of joint exion and other postural information Fires AP more quickly when stimulus begins but maintains regular ring of AP throughout the stimulus application Nociceptor transmissions are often received as once they reach the brain 0 Afferent neurons cross spinal column therefore pain on the left side of the body is processed by the right side of the brain and travel up spinal cord through interneurons in the of the spinal cord 0 lnterneuron branches into RAS which processes the emotional part of pain causes awakeness alertness and arousal responsible for the suffering associated with pain 0 Also branches in to Thalamus where interneuron directs AP to in the cerebral cortex where the sensation of pain ca n be processed 0 Pain may be increased by in ammation is caused by two main mechanisms Chemical formation of Bradykinin Serotonin Prostagandins Substance P Decreases threshold of nociceptors and increases their sensitivity leading to increase in pain sensation 1 and painful perception of normally gentle stimuli Spreading of afferent AP which double back down axon branches and stimulate release of Substance P from other nociceptors Activates Mast Cells Promotes histamine release causing vasodilation leading to edema calor and redness Spreads pain by passing toxic soup to neighboring tissues 0 Brain is able to suppress or enhance pain reception based on emotional setting can change the amounts of suffering Pain is increased by anxiety and focusing on pain Pain is decreased by fear and ght ight response are a type of neurotransmitter they inhibit release of substance P from nociceptor May be activated by meditation and acupuncture lmitated pharmaceutically by e like Morphine Sensation of is also processed in the somatosensory cortex 0 Afferent neurons cross spinal column therefore pain on the left side of the body is processed by the right side of the brain and travel up spinal cord through interneurons in the of the spinal cord 0 Each body part has its own processing region allowing for precise localization of touch 0 Certain body parts feet hands ngers lips get more space devoted to sensation than others not relative to actual body part size but relative to sensitivity 0 Occurs when most strongly activated signal pathway de activates surrounding signal pathways allowing the body to pinpoint the region where the stimulus is most intense VOLUNTARY MOTOR CONTROL Axons of somatic efferent neurons SENs are large and unmyelated and branch once they reach the skeletal muscle 0 The cell bodies of each SEN receives thousands of synaptic inputs from interneurons esp at r May be excitatory characterized by depolarization and glutamate neurotransmitter May be inhibitory characterized by hyperpolarization and Glycine or GABA neurotransmitter EPSP must be gt lPSP in order to activate an SEN one SEN and the muscle ber it innervates 0 Large Motor Unit one SEN that innervates many muscle bers responsible for control of large muscles 0 Small Motor Unit one SEN that innervates only a few muscle bers responsible for ne motor control Each AP causes a weak contraction in the muscle but it is not strong enough for signi cant motor movement this must be accomplished by ring of AP in quick succession and activating many muscle cells simultaneously of motor units 0 AP in SEN are ALWAYS EXCITATORY Relaxation only occurs when AP stops 0 muscles that must be contracted in order for movement to occur 0 muscles that must be relaxed in order for movement to occur AP has to be inhibited in neurons that innervate these muscles 0 Two descending pathways to control spinal motor neurons 0 starting from primary motor cortex responsible for ne motor control 0 responsible for large muscle control and postural adjustments 0 Descending axons branch diverge and activate many different interneurons these interneurons can then converge and make synaptic contact with spinal motor neurons Cepyrigh i E1 The M GGFHW Hi Cempenies Ine Permieeien required for reproduelien or display Higher centers ll Seneorlmotor oerlex a Easel nuelei lll i Tllellemue viii i Breinelem i quot ell Cerebellum i Brain stern and epinaieerd g Meter centre Afferent Meter neurelhe hierarchy neurone limele emmoh 39 Highesrlevel pathwan Middle level Fleeeptore Muscle iibere Local level More details on Myotatic and Inverse Myotatic Re exes o Tendons join muscles to bones o INVERSE MYOTATIC Forcesensitive receptors 1 respond to increased muscle contraction force by inhibiting motor neurons to agonist muscle and stimulating motor neurons to antagonist muscle 0 MYOTATIC Stretchsensitive receptors 1 respond to increased muscle stretch by activating motor neurons to the agonist muscle and inhibiting motor neurons to the antagonist muscle 0 Two types of SENs o F the normal motor neurons connect to the bers that do the work of the muscle 0 y cause contraction of muscle bers that are not involved in the actual muscle contraction but can activatedeactivate muscle spindle receptors 0 They must work together to begin or and maintain y muscle contraction Copyright II The ll lEGE39a H Hillll Companies llrm Permission requiem for repmvcmclla m s Capsule lntralusal muscle a fibers musrzle Splil39ldll Stretch receptor A eirent l39i nerve fibers Extremism muscle fiber l Golgi tendon 123 organ Tendon N S YMPATHETIC AND PARASYMPATHETIC SYSTEMS ANS subdivision of peripheral nervous system Innervates all tissues other than skeletal muscle Made up of visceral efferent neurons VEN ANS is divided anatomically based on region of CNS that contains the cell bodies 0 Cell bodies contained in Thoracic and Lumbar regions Most active during periods of physical or emotional stress 0 Cell bodies contained in Cranial and Sacral regions Most active during periods of rest and digestion Also responsible for sexual arousal 0 There is no ANS stemming from the Cervical region ANS Requires multiple neurons between CNS and target tissue SEN only needs a single neuron stemming from the CNS 0 Regions of peripheral neuronal cell body concentration Sympathetic ganglia are generally centralized and close to spinal cord gangHa abdominal ganglia Adrenal medulla functions as an endocrine gland and is essentially just a neuronal cell body ls capable of dumping neurotransmitters epinephrine and norepinephrine directly into the bloodstream Parasympathetic ganglia are generally close to or inside of target organs O nerves are activated by ACh and have nACh receptors 0 nerves are activated by ACh in parasympathetic system and sweat glands or norepinephrine in sympathetic system Agonists capable of activating a receptor Antagonists capable of inactivating or preventing activation of a receptor
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