EXSC%224%Exam%1:%CH%11-13%Study%Guide%Exam%material:%11.1-11.10,%12.1-12.8,%12.10-12.11,%13.5,%fig.%13.13%%Learning%objectives%for%chapter%11%11.1%Learning%objectives%List%the%basic%functions%of%the%nervous%system.%• Nervous%system%has%3%functions%1. Sensory%input:%sensory%receptors%detect%changes%inside%and%outside%the%body%2. Integration:%processing%of%the%sensory%input%to%decide%what%to%do%3. Motor%output:%nervous%system%activates%effector%organs%(muscles%and%glands)%to%cause%a%response%o Ex:%see%a%red%light%while%driving%(sensory%input),%nervous%system%recognizes%what%this%info%means%and%what%to%do%(integration),%foot%hits%the%brake%(motor%output)%Explain%the%structural%and%functional%divisions%of%the%nervous%systems.%• Central%nervous%system%(CNS)%o Brain%and%spinal%cord%o Control%center%of%the%nervous%system%o Interprets%sensory%information%and%dictates%motor%output%• Peripheral%nervous%system%(PNS)%o Consists%of%nerves%that%extend%from%the%brain%and%spinal%cord%§ Spinal%nerves:%carry%impulses%to%and%from%spinal%cord%§ Cranial%nerves:%carry%impulses%to%and%from%the%brain%o Contains%ganglia:%collections%of%neuron%cell%bodies%o Two%divisions:%afferent%(sensory)%and%efferent%(motor)%§ Afferent%• Nerve%fibers%that%carry%impulses%to%the%central%nervous%system%from%sensory%receptors%• Somatic%sensory%fibers%convey%impulses%from%skin,%skeletal%muscles,%and%joints%• Visceral%sensory%fibers%convey%impulses%from%the%visceral%organs%• Keeps%the%CNS%aware%of%what%is%going%on%in%and%out%of%the%body%§ Efferent%• Transmits%impulses%from%the%CNS%to%effector%organs%• Has%2%parts%o Somatic%nervous%system%§ Somatic%nerve%fibers%that%conduct%impulses%from%the%CNS%to%skeletal%muscles%§ Voluntary%o Autonomic%nervous%system%§ Visceral%motor%nerve%fibers%that%regulate%activity%of%smooth%and%cardiac%muscles%and%glands%§ Involuntary%§ Has%2%subdivisions%• Sympathetic:%stimulates%• Parasympathetic:%inhibits%%11.2 Learning%objectives%List%the%types%of%neuroglia%and%cite%their%functions.%• Neuroglia:%supporting%cells%to%neurons%o Glial%cells%in%CNS%§ Astrocytes%• Most%abundant,%versatile,%lots%of%branches%• Cling%to%neurons,%synaptic%endings,%and%capillaries%• Support%and%brace%neurons%(hold%them%in%place)%• Help%determine%capillary%permeability%§ Microglia%• Small,%ovoid%cells%with%thorny%processes%• 1st%line%of%defense%• alerts%immune%system%to%any%problems%• migrate%toward%injured%neurons%• phagocytize%§ ependymal%cells%• line%cavities%of%brain%and%spinal%column%• separate%CNS%interstitial%fluid%from%cerebrospinal%fluid%• produce%cerebrospinal%fluid%at%choroid%plexuses%• water%tight%seal%• may%be%ciliated%to%help%with%circulation%of%cerebrospinal%fluid%§ oligodendrocytes%• make%myelin%• processes%wrap%around%axons%in%CNS%to%insulate%• myelin%speeds%up%transmission%• multiple%sclerosis:%demyelination%in%CNS%o Glial%cells%in%PNS%§ Satellite%cells%• Surround%neuron%cell%bodies%• Same%function%as%astrocytes:%support%and%brace%neurons%§ Schwann%cells%• Surround%nerve%fibers%to%form%myelin%sheath%• Vital%to%regeneration%of%damaged%peripheral%nerve%fibers%%11.3%Learning%objectives%Define%neuron,%describe%its%important%structural%components,%and%relate%each%to%a%functional%role.%• Characteristics%o Typically%large%o Highly%specialized%cells%o Extreme%longevity:%with%good%nutrition,%they%last%a%lifetime%o Amitotic:%can’t%divide%o High%metabolic%rate:%use%lots%of%oxygen%and%glucose%• Neuron%cell%body%(soma)%o Biosynthetic%center%of%the%neuron:%produces%all%the%necessary%proteins%and%chemicals%o Has%a%really%well-developed%Rough%ER%(called%Nissl%bodies)%and%Golgi%apparatus%for%producing%and%packaging%all%the%necessary%neurotransmitters%that%are%released%following%an%action%potential%o Most%neuron%cell%bodies%are%in%the%CNS%§ Protected%here%by%the%skull%and%vertebral%column%§ Clusters%of%cell%bodies%in%the%CNS%are%called%nuclei%(called%ganglia%in%the%PNS)%• Neuron%processes:%arm-like%extensions%from%the%cell%body%o Include%dendrites%and%axons%o PNS%consists%mostly%of%neuron%processes%o Dendrites%§ Diffusely%branching%extensions%§ Has%the%same%organelles%as%the%cell%body%§ Main%receptive/input%region%§ Large%surface%area%for%receiving%signals%from%other%neurons%§ Send%signals%to%the%cell%body,%typically%as%graded%potentials%o Axon%§ Structure%• Each%neuron%has%only%one%• Axon%hillock:%initial%region%• Some%are%short%and%some%are%really%long%• Axon%collaterals:%Occasional%branches%along%its%length%• Terminal%branches:%Lots%of%branching%at%the%end%(10,000%or%more)%• Axon%terminals:%knoblike%endings%of%the%terminal%branches%§ Functional%characteristics%• Conducting%region%of%the%neuron:%generates%nerve%impulses%and%transmits%them%• Nerve%impulse%generated%at%the%axon%hillock%and%travels%to%the%axon%terminals%(secretory%region%of%the%neuron)%o Neurotransmitters%released%from%the%axon%terminals%when%the%impulse%reaches%them%• Has%organelles%but%NO%rough%ER%or%Golgi%apparatus%§ Axonal%transport%• Cytoskeletal%elements%help%move%substances%in%the%neuron%along%the%axon%• Anterograde%movement:%movement%away%from%the%cell%body%o Things%transported%this%way:%mitochondria,%membrane%components%to%renew%the%axon%plasma%membrane,%enzymes%for%neurotransmitter%synthesis%• Retrograde%movement:%movement%to%the%cell%body%o Things%transported%this%way:%organelles%that%need%to%be%degraded%or%recycled%o Also%important%means%of%intracellular%communication%Differentiate%between%(1)%a%nerve%and%a%tract,%and%(2)%a%nucleus%and%a%ganglion.%• Nerve%vs%tract%o Nerve:%bundles%of%axons%in%the%CNS%o Tract:%bundles%of%axons%in%the%PNS%• Nucleus%vs%ganglion%o Nucleus:%collection%of%neuron%cell%bodies%in%the%CNS%o Ganglion:%collection%of%neuron%cell%bodies%in%the%PNS%Explain%the%importance%of%the%myelin%sheath%and%describe%how%it%is%formed%in%the%c e ntr al%and%peripheral%nervous%systems.%• Myelin%sheath%o Whitish,%fatty%protein-lipoid%o Function:%insulates%fibers%and%increases%the%transmission%speed%of%nerve%impulses%o Associated%with%axons%• Myelination%in%the%PNS%o Formed%by%Schwann%cells%o Schwann%cells%wrap%themselves%around%the%axons%in%concentric%layers%(like%wrapping%gauze%around%an%injured%finger)%o Channel%and%carrier%proteins%are%absent,%helps%them%be%good%electrical%conductors%o
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