Nervous System Organization PDF

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Dr. Daniel Stern-Cardinale...

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Nervous(System(Organization Friday, March 24, 2017

9:05 AM

• Nervous(system(organization ○ CC(animal(nervous(systems • Glial(cells ○ CC(glial(cells • Central(Nervous(System • Peripheral(Nervous(system ○ SEQ(NS(signal(pathway ○ CC(CNS,(PNS • Vertebrate(Brain ○ SEQ(brain(devo ○ CC(brain(structures • Big(picture ○ Sense,(react(to(environment--BYA ○ Increase(survival,(reproduction(in(changing(environments ○ Increase(body(complexity--->(increase(in(NS(complexity 1. Nervous(system(organization a. Cnidarians((basal(eumetazoans) § Simplest(animals(with(nervous(system § Nerve%net-interconnected(neurons § No(central(control(organ § Impulses(in(both(directions,(spread(through(net b. Echinoderms((deuterostomes) § Nerve%ring-central(control(structure § Signals(radial(nerves-->(signals(muscles c. Bilateria--lost(of(variation i. Platyhelminthes-planarians 1) Simplest(clearly(defined(CNS 2) Brain,(eyespots(at(anterior 3) Ladder-type nervous system

3) Ladder type(nervous(system a) 2(longitudinal(nerve(cords b) Transverse(nerves(("rungs"(of(the(ladder) ii. Annelids(and(arthropods 1) More(complex(brains 2) Some(degree(of(cephylization 3) Ganglia-segmentally(arranged(clusters(of(neurons 4) Having(the(ability(to(specialized(is(a(huge(advancement d. Vertebrates § Brain(and(spinal(cord-CNS § Nerves(and(ganglia-PNS e. Nervous(system(and(lifestyle i. squid--fast(moving-->(complex 1) High(level(problem(solving ii. Chitin--slow(moving-->(simple 2. Glial%Cells%(Glia)((fig(49.3 a. Adult(glial(cells § Many(functions i. Myelination 1) Oligodendrocytes in(CNS 2) Schwann%cells in(PNS b. Radial%Glia § Form(tracks(in(developing%embryo § Newly(formed(neurons(migrate(from(neural(tube(along(tracks § Cell(ends(up(at(the(outer(surface § Allow(cells(to(get(from(the(inner(surface(of(the(central(nervous(sy central(nervous(system 3. Central%Nervous%System%(CNS) ○ Brain(and(spinal(cord a. Brain-central(control(organ § Brain(is(developed(from(the(anterior(end(of(the(dorsal(cord § Catvites--ventricles(in(the(middle □ Filled(with(cerebrospinal(fluid § White(matter-made(up(of(myelinated(axons § Gray(matter-unmyelinated(axons(and(cell(bodies b. Spinal%cord § Link(between(brain(and(the(rest(of(the(NS

stem(to(the(outer(part(of(the(

§ § § § i.

Dorsal,(neck/back,(within(spine Small(central(canal(with(fluid Gray(matter(surrounds(canal White(matter(sourrounds(gray Spinal(cord(functions 1) Transmits(impulses(to/from(brain 2) Reflex%actions-rapid,(involuntary(response(to(stimulus a) Ex.(Knee-jerk(reflex b) Quad(stretched(unexpectedly-->(helps(to(stay(upright c) Reflex(arc 4. Peripheral%nervous%system%(PNS)% ○ Nervous(tissue(not(part(of(CNS--transmits(to/from(CNS--sensory(rece a. Sensory(receptors § Detection(of(stimuli § Visual,(auditory,(chemical,(etc b. Nerves § Cranial%nerves □ Originate(in(hind(part(of(brain □ Innervate(head,(upper(body § Spinal%nerves □ Originate(in(dorsal(hollow(nerve(cord □ Innervate(entire(body c. Functional(components(of(PNS(fig(49.8 i. Afferent%(sensory)-sensory(receptor-->(CNS □ Receptors(involved,(not(effectors □ Visceral-not(aware(of((blood(pressure(etc.) □ Somatic-aware(of((visioin) ii. Efferent%(motor) 1) CNS-->(effectors 2) 2(components a) Motor%system i) Efferent(neurons-->(skeletal(muscle ii) Voluntary(and(reflexes iii) No(receptors b) Autonomic%nervous%system i) Efferent(neurons-->(glands,(heart,(smooth(muscl ii) What CNS controls that we are not aware of

tors(and(nerves

ii) What(CNS(controls(that(we(are(not(aware(of iii) 3(divisions((fig(49.9) } Controls(digestive,(cardiovascular,(excretor } Enteric – Digestive(tract,(pancreas,(gall(bladder } Parasympathetic – Rest(and(digest – Slows(heart } Sympathetic – Fight(or(flight – Accelerates(heart § Pathway(of(a(signal □ Stimulus □ Sensory(receptor □ Afferent(neuron □ CNS □ Efferent(neuron □ Motor(or(autonomic(system □ Effector 5. Vertebrate(brain a. Embryonic(development § Neural(tube § Single(tube(of(tissue § Anterior-->(brain § Posterior-->(spinal(cord i. Embryonic(brain(regions(fig(49.11 1) Forebrain--telencephalonm(dienchephalon 2) Midbrain--mesencephalon 3) Hindbrain--metenchephalon,(meylencephalon b. Comparison(of(vertebrate(brains i. Relative(size(of(3(main(regions(varies ii. Reflects(importance(of(particular(functions c. Structures(and(functions i. Cerebrum □ Most(prominent(part(of(the(brain □ Develop(from(the(embryonic(forebrain □ Higher order thinking

,(endocrine

Higher(order(thinking Complex(problem(solving Planning(ahead Voluntary(movement Learning,(emotion,(memory,(perception Divisions a) Right/left(hemispheres b) Left/right(reversed(perception/control c) Corpus%callosum-thick(band(of(axons,(connects(left(an ii. Cerebellum 1) Back(of(brain 2) Hindbrain-->metechepalon) 3) Movement,(balance 4) Motor(skills.(Coordination 5) Position(of(joints,(length(of(muscles 6) Input(from(ears,(eyes 7) Damage(leads(to(permanent(loss(of(coordination iii. Diencephalon 1) Derived(from(forebain 2) Gives(rise(to(2(structures a) Thalamus-main(input(center(for(sensory(info(to(cereb i) Routes(to(correct(area b) Hypothalamus i) Regulates(pituitary ii) Also(hunger,(thirst,(sex,(rage iv. Brains(tem 1) Midbrain,(pons,(medulla(oblongata 2) Midbrain-receivs,(integrates,(routes(sensory(info 3) Pons((from(hindbrain)-respiratory(and(sleep(centers 4) Medulla(oblongata((from(hindbrain)-continuous(with(spina 5) Basic(life(functions--respiration,(heart(beat,(blood(pressure 6) Swallowing,(coughing,(vomiting □ □ □ □ □ 1)

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