BIOL 1040 Exam 3 Study Guide
I I I I I
Chapter I28
-Nervous ISystem: Ian Ianimal Iorgan Isystem Icomprised Iof Ia Inetwork Iof Ispecialized Iinteracting Icells
I(neurons) Ithat Ifunctions Iin Ithe Idetection, Iprocessing Iand Iresponse Ito Iinternal Iand Iexternal Istimuli.
INervous Isystem Iis Idivided Iinto Itwo Ifunction Iparts; ICentral Inervous Isystem Iand IPeripheral Inervous
Isystem
-Three IMain IFunctions:
1. Sensory IInput: Iconduct Isignals Ifrom Ireceptors Ito ICNS.
2. Integration: Ianalysis I& Iinterpretation Iof Isensory Isignals, I& Iformation Iof Iappropriate
Iresponses.
3. Motor IOutput: Iconduct Isignals Ifrom ICNS Ito Ieffectors Ithat Iexecute Ia Iresponse.
-The ICentral INervous ISystem: Icomprised Iof Ithe Ibrain I& Ispinal Icord.
Brain: Imaster Icontrol Icenter.
Spinal Icord: Iconveys Iinformation Ito Ithe Ibrain; Iintegrates Isimple Ireflex Iresponses.
ICavities: Ifilled Iwith Icerebrospinal Ifluid; IVentricles Iof Ithe Ibrain, Icentral Icanal Iof Ithe Ispinal
Icord I& Isurrounding Ithe Ibrain.
-Peripheral INervous ISystem: Icomprised Iof Inerves Iand Iganglia Ioutside Ithe ICNS Ithat Icarry Isignals
Iinto I& Iout Iof Ithe ICNS. ICranial I& Ispinal Inerves; IConnecting Iganglia. ICarries Iinfo Ito Iand Ifrom ICNS
-Cranial INerves: Itwelve Ipairs Iof Inerves Ithat Iarise Idirectly Ifrom Ithe Ibrain, Inot Ifrom Ithe Ispinal Icord,
Iand Ipass Ithrough Iseparate Iapertures Iin Ithe Iskull.
-Ganglia: Iclusters Iof Ineuron Icell Ibodies.
-Nerves: Ibundles Iof Ineurons Iwrapped Iin Iconnective Itissue.
-Neurons: Ifunctional Iunits Iof Ithe Inervous Isystem; Iperceives Istimuli Iand Itransmits/conducts
Iinformation I(impulses) Ito Iother Icells. IThree Imain Itypes:
1. Sensory Ineurons: Iconvey Isignals Ifrom Isensory Ireceptors Ito Ithe ICNS.
2. Interneurons: Iare Ilocated Ientirely Iin Ithe ICNS, Iintegrate Iinformation I& Isend Iit Ito Imotor
Ineurons.
3. Motor Ineurons: Itransmit Iimpulses Ifrom Ithe Icentral Inervous Isystem Ito Imuscles Ieffectors
ItoIeffect Icontraction
-Process Iof Ineurons:
1. Sensory Ireceptor Idetects Istretch Istimulus.
2. Sensory Ineuron Isends Iimpulse Ito Ithe ICNS I(spinal Icord).
3. Impulse Iis Itransferred Ifrom Ithe ICNS Ito Imotor Ineurons
4. And Iinterneurons.
-Motor Ineurons I& Isensory Ineurons I(of Ithe IPNS) Iare Igenerally Ilonger Ithan Iinterneurons. IThese
IareImyelinated Ito Ihelp Ispeed Iup Iimpulse Itransmission I(part Iof Ithe Ifunction Iof Ithe Imyelin Isheath).
-Interneurons I(of Ithe ICNS) Iare Ifrequently Inon Imyelinated I(e.g. Ias Iin Ithe I“gray Imatter” Iof Ithe Ispinal
Icord), Ibecause Ifirst Ithey Iare Irelatively Ishort, Iand Ithus Idon’t Ineed Ito Ibe Ias Ifast Ias Ithe Iothers; Iand
Isecond, Ithey Ioften Iinteract Iwith Iaxons Iof Iadjacent Ineurons.
-Neurons Iare Imade Iup Iof:
Cell IBody: Icontains Ithe Inucleus Iand Iother Iorganelles.
Dendrites: Ireceive Isignals Ifrom Isensory Ireceptors Ior Iother Ineurons.
Axon: Iportion Iof Ineuron Ithat Itransmits Iimpulses Ito Iother Ineurons Ior Icells.
Myelin ISheath: Ia Isheath Iof Icells Ithat Iinsulate Ithe Iaxon Iand Ispeeds Iup Itransmit Iprocess
ISchwann Icells Iin Ithe IPNS; IOligodendrocytes Iin Ithe ICNS.
-Schwann Icells: Ithe Isupporting Icells Iof Ithe IPNS. IThey Iwrap Ithemselves Iaround Isingle Inerve Iaxons,
Imaking Iup Ia Isingle Isegment Iof Ian Iaxon's Imyelin Isheath
-Glial ICells
Astrocytes: Itransfer Inourishment Ifrom Icapillaries Ito Ithe Ineuron.
, BIOL 1040 Exam 3 Study Guide
I I I I I
Oligodendrocytes: Iform Ithe Imyelin Isheath Iaround Ithe Iaxons Iof Ineurons I& Inerve Ifibers Iin
ICNS; Iwrap Ithemselves Iaround Inumerous Iaxons Iat Ionce
Microglia: Iresident Imacrophages Iof Ithe Inervous Isystem; Ithey Iphagocytize Iinfectious Iagents
Iand Ineural Idebris.
-Nerve Ifunction Idepends Ion Icharge Idifferences Iacross Ineuron Imembranes
-Pumps Iworks Iopposite Iof Iosmosis; Imoves Istuff Ifrom Ilow Ito Ihigh; Iagainst Ithe Iconcentration
Igradient
-At Irest Iit Iwants Ito Ipump Isodium Iout Iand Ipotassium Iin; Ilots Iof INa Ion Ioutside; Ilots Iof IK Iin Iinside
-Outside I= Ipositive; IInside I= Inegative.
-Resting Ipotential I= I-70 Imv.
-Created I& Imaintained Iby Ithe INa/K Ipump.
▪ [Na+] Ihigh Ioutside Ineuron.
▪ [K+] Ihigh Iinside Ineuron.
-Collapsed Iby INa+ I& IK+ Iion Ichannels.
-Na+ I & I K+ Ipump:
1. Carrier Ihas Ia Ishape Ithat Iallows Iit Ito Itake Iup I3 INA+
2. ATP Iis Isplit Iand Iphosphate Igroup Iattaches Ito Icarrier
3. Change Iin Ishape Iresults Iand Icause Iscarier Ito Irelease I3 INA+ Ioutside Icell
4. Carrier Ihas Ia Ishape Ithat Iallows Iit Ito Itake Iup I2 Ik+
5. Phosphate Igroup Iis Ireleased Ifrom Icarrier
6. Changes Iin Ishape Iresult Iand Icauses Icarrier Ito Irelease I2 IK+ Iinside Icell
-1 IATP Imakes I3 Isodium Iions Igo Iout Iand I2 IK Igo Iin; IHappens Ibetween Isignals
-A INerve ISignal IBegins IAs Ia IChange Iin Ithe IMembrane IPotential.
-Stimulus: Iany Ifactor Ithat Icauses Ia Inerve Isignal Ito Ibe Igenerated; IAlters Ithe Ipermeability Iof Ia
Iportion Iof Ithe Imembrane; IAllows Iions Ito Ipass Ithrough; IChanges Ithe Imembrane’s Ivoltage; IAn Iaction
Ipotential Imay Ibe Iinitiated; IChange Iin Ivoltage Ican Ibe Imonitored
-Tracking Ian Iaction Ipotential:
1. Resting Istate: IVoltage-gated INa+ Iand IK+ Ichannels Iare Iclosed; Iresting Ipotential Iis Imaintained Iby
Iungated Ichannels.
2. Depolarization: IA Istimulus Iopens Isome INa+channels; Iif Ithreshold Iis Ireached, Ian Iaction Ipotential
Iis Itriggered.
3. Additional INa+channels Iopen, INa Irushes Iin IK+ Ichannels Iare Iclosed; Iinterior Iof Icell Ibecomes
Imore Ipositive.
4. Repolarization: I Na+ Ichannels I close I and I inactivate; I K +channels I open, I and I K+ Irushes I out;
I interior Iof Icell Iis Imore Inegative Ithan Ioutside.
5. The IK+Ichannels Iclose Irelatively Islowly, Icausing Ia Ibrief Iundershoot.
6. Return Ito Iresting Istate.
-Resting Ipotentials Iof Ineurons Irange Ifrom I-60 Ito I-70 ImV; Ithreshold Ipotentials Irange Ifrom I-40 Ito
-55 ImV; Iaction Ipotentials Irange Ifrom I+30 Ito I+60 ImV.
-Migrating Iaction Ipotential Icontinues Ialong Ithe Ientire Ilength Iof Ithe Iaxon; INa/K Ipump Ire-
Iestablishes Icorrect Imembrane Iresting Ipotential.
-Myelinated Ineurons Ioccur Imainly Iin Ithe Iperipheral Inervous Isystem Iwhere Iimpulses Imust
Inormally Itravel Ifurther. I(Saltatory IConduction)
-Unmyelinated Ineurons Ioccur Imainly Iin Ithe ICNS Ias Iinterneurons, Iwhere Iimpulses Itravel Imuch
Ishorter Idistances Ibetween Isensory I& Imotor Ineurons. I(Continuous IConduction)
-Neurons Icommunicate Iat Isynapses
I I I I I
Chapter I28
-Nervous ISystem: Ian Ianimal Iorgan Isystem Icomprised Iof Ia Inetwork Iof Ispecialized Iinteracting Icells
I(neurons) Ithat Ifunctions Iin Ithe Idetection, Iprocessing Iand Iresponse Ito Iinternal Iand Iexternal Istimuli.
INervous Isystem Iis Idivided Iinto Itwo Ifunction Iparts; ICentral Inervous Isystem Iand IPeripheral Inervous
Isystem
-Three IMain IFunctions:
1. Sensory IInput: Iconduct Isignals Ifrom Ireceptors Ito ICNS.
2. Integration: Ianalysis I& Iinterpretation Iof Isensory Isignals, I& Iformation Iof Iappropriate
Iresponses.
3. Motor IOutput: Iconduct Isignals Ifrom ICNS Ito Ieffectors Ithat Iexecute Ia Iresponse.
-The ICentral INervous ISystem: Icomprised Iof Ithe Ibrain I& Ispinal Icord.
Brain: Imaster Icontrol Icenter.
Spinal Icord: Iconveys Iinformation Ito Ithe Ibrain; Iintegrates Isimple Ireflex Iresponses.
ICavities: Ifilled Iwith Icerebrospinal Ifluid; IVentricles Iof Ithe Ibrain, Icentral Icanal Iof Ithe Ispinal
Icord I& Isurrounding Ithe Ibrain.
-Peripheral INervous ISystem: Icomprised Iof Inerves Iand Iganglia Ioutside Ithe ICNS Ithat Icarry Isignals
Iinto I& Iout Iof Ithe ICNS. ICranial I& Ispinal Inerves; IConnecting Iganglia. ICarries Iinfo Ito Iand Ifrom ICNS
-Cranial INerves: Itwelve Ipairs Iof Inerves Ithat Iarise Idirectly Ifrom Ithe Ibrain, Inot Ifrom Ithe Ispinal Icord,
Iand Ipass Ithrough Iseparate Iapertures Iin Ithe Iskull.
-Ganglia: Iclusters Iof Ineuron Icell Ibodies.
-Nerves: Ibundles Iof Ineurons Iwrapped Iin Iconnective Itissue.
-Neurons: Ifunctional Iunits Iof Ithe Inervous Isystem; Iperceives Istimuli Iand Itransmits/conducts
Iinformation I(impulses) Ito Iother Icells. IThree Imain Itypes:
1. Sensory Ineurons: Iconvey Isignals Ifrom Isensory Ireceptors Ito Ithe ICNS.
2. Interneurons: Iare Ilocated Ientirely Iin Ithe ICNS, Iintegrate Iinformation I& Isend Iit Ito Imotor
Ineurons.
3. Motor Ineurons: Itransmit Iimpulses Ifrom Ithe Icentral Inervous Isystem Ito Imuscles Ieffectors
ItoIeffect Icontraction
-Process Iof Ineurons:
1. Sensory Ireceptor Idetects Istretch Istimulus.
2. Sensory Ineuron Isends Iimpulse Ito Ithe ICNS I(spinal Icord).
3. Impulse Iis Itransferred Ifrom Ithe ICNS Ito Imotor Ineurons
4. And Iinterneurons.
-Motor Ineurons I& Isensory Ineurons I(of Ithe IPNS) Iare Igenerally Ilonger Ithan Iinterneurons. IThese
IareImyelinated Ito Ihelp Ispeed Iup Iimpulse Itransmission I(part Iof Ithe Ifunction Iof Ithe Imyelin Isheath).
-Interneurons I(of Ithe ICNS) Iare Ifrequently Inon Imyelinated I(e.g. Ias Iin Ithe I“gray Imatter” Iof Ithe Ispinal
Icord), Ibecause Ifirst Ithey Iare Irelatively Ishort, Iand Ithus Idon’t Ineed Ito Ibe Ias Ifast Ias Ithe Iothers; Iand
Isecond, Ithey Ioften Iinteract Iwith Iaxons Iof Iadjacent Ineurons.
-Neurons Iare Imade Iup Iof:
Cell IBody: Icontains Ithe Inucleus Iand Iother Iorganelles.
Dendrites: Ireceive Isignals Ifrom Isensory Ireceptors Ior Iother Ineurons.
Axon: Iportion Iof Ineuron Ithat Itransmits Iimpulses Ito Iother Ineurons Ior Icells.
Myelin ISheath: Ia Isheath Iof Icells Ithat Iinsulate Ithe Iaxon Iand Ispeeds Iup Itransmit Iprocess
ISchwann Icells Iin Ithe IPNS; IOligodendrocytes Iin Ithe ICNS.
-Schwann Icells: Ithe Isupporting Icells Iof Ithe IPNS. IThey Iwrap Ithemselves Iaround Isingle Inerve Iaxons,
Imaking Iup Ia Isingle Isegment Iof Ian Iaxon's Imyelin Isheath
-Glial ICells
Astrocytes: Itransfer Inourishment Ifrom Icapillaries Ito Ithe Ineuron.
, BIOL 1040 Exam 3 Study Guide
I I I I I
Oligodendrocytes: Iform Ithe Imyelin Isheath Iaround Ithe Iaxons Iof Ineurons I& Inerve Ifibers Iin
ICNS; Iwrap Ithemselves Iaround Inumerous Iaxons Iat Ionce
Microglia: Iresident Imacrophages Iof Ithe Inervous Isystem; Ithey Iphagocytize Iinfectious Iagents
Iand Ineural Idebris.
-Nerve Ifunction Idepends Ion Icharge Idifferences Iacross Ineuron Imembranes
-Pumps Iworks Iopposite Iof Iosmosis; Imoves Istuff Ifrom Ilow Ito Ihigh; Iagainst Ithe Iconcentration
Igradient
-At Irest Iit Iwants Ito Ipump Isodium Iout Iand Ipotassium Iin; Ilots Iof INa Ion Ioutside; Ilots Iof IK Iin Iinside
-Outside I= Ipositive; IInside I= Inegative.
-Resting Ipotential I= I-70 Imv.
-Created I& Imaintained Iby Ithe INa/K Ipump.
▪ [Na+] Ihigh Ioutside Ineuron.
▪ [K+] Ihigh Iinside Ineuron.
-Collapsed Iby INa+ I& IK+ Iion Ichannels.
-Na+ I & I K+ Ipump:
1. Carrier Ihas Ia Ishape Ithat Iallows Iit Ito Itake Iup I3 INA+
2. ATP Iis Isplit Iand Iphosphate Igroup Iattaches Ito Icarrier
3. Change Iin Ishape Iresults Iand Icause Iscarier Ito Irelease I3 INA+ Ioutside Icell
4. Carrier Ihas Ia Ishape Ithat Iallows Iit Ito Itake Iup I2 Ik+
5. Phosphate Igroup Iis Ireleased Ifrom Icarrier
6. Changes Iin Ishape Iresult Iand Icauses Icarrier Ito Irelease I2 IK+ Iinside Icell
-1 IATP Imakes I3 Isodium Iions Igo Iout Iand I2 IK Igo Iin; IHappens Ibetween Isignals
-A INerve ISignal IBegins IAs Ia IChange Iin Ithe IMembrane IPotential.
-Stimulus: Iany Ifactor Ithat Icauses Ia Inerve Isignal Ito Ibe Igenerated; IAlters Ithe Ipermeability Iof Ia
Iportion Iof Ithe Imembrane; IAllows Iions Ito Ipass Ithrough; IChanges Ithe Imembrane’s Ivoltage; IAn Iaction
Ipotential Imay Ibe Iinitiated; IChange Iin Ivoltage Ican Ibe Imonitored
-Tracking Ian Iaction Ipotential:
1. Resting Istate: IVoltage-gated INa+ Iand IK+ Ichannels Iare Iclosed; Iresting Ipotential Iis Imaintained Iby
Iungated Ichannels.
2. Depolarization: IA Istimulus Iopens Isome INa+channels; Iif Ithreshold Iis Ireached, Ian Iaction Ipotential
Iis Itriggered.
3. Additional INa+channels Iopen, INa Irushes Iin IK+ Ichannels Iare Iclosed; Iinterior Iof Icell Ibecomes
Imore Ipositive.
4. Repolarization: I Na+ Ichannels I close I and I inactivate; I K +channels I open, I and I K+ Irushes I out;
I interior Iof Icell Iis Imore Inegative Ithan Ioutside.
5. The IK+Ichannels Iclose Irelatively Islowly, Icausing Ia Ibrief Iundershoot.
6. Return Ito Iresting Istate.
-Resting Ipotentials Iof Ineurons Irange Ifrom I-60 Ito I-70 ImV; Ithreshold Ipotentials Irange Ifrom I-40 Ito
-55 ImV; Iaction Ipotentials Irange Ifrom I+30 Ito I+60 ImV.
-Migrating Iaction Ipotential Icontinues Ialong Ithe Ientire Ilength Iof Ithe Iaxon; INa/K Ipump Ire-
Iestablishes Icorrect Imembrane Iresting Ipotential.
-Myelinated Ineurons Ioccur Imainly Iin Ithe Iperipheral Inervous Isystem Iwhere Iimpulses Imust
Inormally Itravel Ifurther. I(Saltatory IConduction)
-Unmyelinated Ineurons Ioccur Imainly Iin Ithe ICNS Ias Iinterneurons, Iwhere Iimpulses Itravel Imuch
Ishorter Idistances Ibetween Isensory I& Imotor Ineurons. I(Continuous IConduction)
-Neurons Icommunicate Iat Isynapses
