Quia - Chapter 38

Nervous SystemChapter 38

Chapter 38 Section 1:Structures of the NervousSystemKey VocabularyTermsAdapted from Holt Biology 2008

NeuronA nerve cell that isspecialized toreceive and conductelectrical impulsesAdapted from Holt Biology 2008

Central Nervous System(CNS)The brain and thespinal cord; its mainfunction is to controlthe flow ofinformation in thebody

Peripheral Nervous System(PNS)All of the parts of thenervous system exceptfor the brain and thespinal cord (the centralnervous system);includes the cranialnerves and nerves ofthe neck, chest, lowerback, and pelvis

BrainThe mass of nervetissue that is themain control centerof the nervoussystem

CerebrumThe upper part of thebrain that receivessensation andcontrols movement

BrainstemThe stem like portion ofthe brain that connectsthe cerebralhemispheres with thespinal cord and thatmaintains thenecessary functions ofthe body, such asbreathing andcirculation

CerebellumA posterior portion ofthe brain thatcoordinates musclemovement andcontrolssubconsciousactivities and somebalance functions

Spinal CordA column of nervetissue running fromthe base of the brainthrough the vertebralcolumn

ReflexAn involuntaryand almostimmediatemovement inresponse to astimulus

Content ObjectivesWrite these down!I will be able to identify: The function of the central nervoussystem. The two components of the peripheralnervous system. How a spinal reflex is generated.

Chapter 38 - Section 1:Structures of the NervousSystemNotesAdapted from Holt Biology 2008

The Nervous SystemNeuron: specialized cell of the nervoussystem that carries messages(signaling cell)

The Nervous SystemKey point: The nervoussystem controls andcoordinates functionsthroughout the body andresponds to internal andexternal changes.

Divisions of the nervous system1. Central Nervous System (CNS)2. Peripheral Nervous System (PNS)

Central Nervous System (CNS)a. Brainb. Spinal cord

Peripheral Nervous System (PNS)a. Sensoryb. Motor

Divisions of the Nervous SystemThe NervousSystemis systemSpinalCordMotornervesthatmake upPeripheralnervoussystemwhichconsists ofAutonomicnervoussystemwhich isdivided intoSympatheticnervous systemParasympatheticnervous systemSensorynerves

Structures of the Nervous System

Think, Share, Write #1What is a neuron?

Think, Share, Write #1What is a neuron?A neuron is a specialized cell inthe nervous system, a nerve cell.

5The Brain

1. The Brain is protected by:a. skull: hard bone mass

1. The Brain is protected by:b. meninges:3 layers of tissuecovering the brain

1. The Brain is protected by:c. cerebrospinal fluid:surrounds and absorbs shock

2. Spinal Cord

2. Spinal Cord Protected by:a. vertebrae:bone

2. Spinal Cord Protected by:b. meninges:3 layers oftissue

2. Spinal Cord Protected by:c.cerebrospinalfluid:wraps around,shockabsorber

YOUR TURN With a partner, read the Chapter 38Section 1 Active Reading – Structures ofthe Nervous System 1st - Take turns reading the questionsaloud to each other, alternating questions. 2nd - Take turns reading the selectionaloud to each other, alternating sentencesor paragraphs.Adapted from Holt Biology 2008

YOUR TURN As you read discuss the content. Reread and discuss each question. Writedown the best answer to the question usingfull descriptive sentences. Be prepared to share with the class.2Adapted from Holt Biology 2008Adapted from Holt Biology 2008

4Content ObjectivesWrite these down!I will be able to identify: The function of the central nervoussystem. The two components of the peripheralnervous system. How a spinal reflex is generated.

Four Main Areas of the Brain:1. Cerebrum2. Cerebellum3. Pons4. Medulla

1.Cerebrum:largest, mostprominent part,voluntaryactivities of thebody,intelligence,learning,judgment

Two sections connected by thecorpus callosum

Main Lobes ofthe Cerebrum :FrontalParietalTemporalOccipital

Surfaces of the Brain:1. Cortex : outer surface - gray matter;Process information from senses &Controls body movement

Surfaces of the Brain:2. Medulla: center, white matter;Bundles of myelinated axons

Four Main Areas of the Brain cont. :2. Cerebellum:2nd largest area,coordinates andbalancesactions ofmuscles thatmove the body

Four Main Areas of the Brain cont. :3. Brain Stem:Medulla and PonsConnects brain tospinal cord,regulates flow ofinformation betweenbrain and body andcontrols bloodpressure, heart rate,breathing, swallowingetc.

Four Main Areas of the Brain cont. :4. Thalamus and HypothalamusBetween brain and brain stem

Thalamus – receives information fromsense organs and relays to correctarea of cerebrum

HypothalamusControl centerfor thirst,fatigue, angerand bodytemperature

Figure 35-9 The BrainSection 35-3The Brain

The Spinal CordMaincommunication linkbetween brain andrest of the body.31 pairs of nervesout from the spinalcord and lead to therest of the body.

The Spinal Cord

Reflex: automatic response to astimulus - It is usually a reaction toprotect body

Reflex arc – The nerve pathway 1. sensory receptor,2. spinal cord,3. muscle or gland (effector)

Reflex

Think, Share, Write #2What neurons are involved in aspinal reflex?

Think, Share, Write #2What neurons are involved in aspinal reflex?Sensory neurons, motor neurons,and interneurons are involved in aspinal reflex?

Peripheral Nervous SystemOutside theCentral NervousSystemTransmits fromsense organs toCNS and back tomuscles orglands.

Peripheral Nervous SystemTwo Divisions: Sensory andMotor

The sensorydivision transmitsimpulses fromsense organs such as the earsand taste buds to the CNS.

The motordivisiontransmitsimpulses fromthe CNSsystem to themuscles orglands.

Somatic Nervous SystemRegulates activities underconscious control -skeletalmuscles also controls reflexes

Autonomic Nervous SystemRegulates activities that areautomatic – involuntaryExamples:- heartbeat- contraction of smooth musclesin the digestive system

Two Parts: Autonomic Nervous SystemSympathetic - fight or flightParasympathetic – rest and digest

Two Parts:Sympathetic & ParasympatheticMost organs are controlled by both. Why?

Content ObjectivesWrite these down!I will be able to identify: How the body conducts electricity. How a neuron’s structure allows theneuron to send electrical signals. How a nerve impulse is generated How neurons communicate with eachother.

Chapter 38 Section 2:Neurons and the NerveImpulseKey VocabularyTermsAdapted from Holt Biology 2008

DendriteA cytoplasmicextension of aneuron thatreceives stimuli

AxonAn elongatedextension of aneuron thatcarriesimpulses awayfrom the cellbody

NerveA collection ofnerve fibersthrough whichimpulses travelbetween thecentral nervoussystem and otherparts of the body

Membrane PotentialThe differencein electricpotentialbetween thetwo sides of acell membrane

Action PotentialA sudden changein the polarity of themembrane of aneuron, gland cell,or muscle fiber thatfacilitates thetransmission ofelectrical impulses

SynapseThe junction at which the end of the axon ofa neuron meets the end of a dendrite or thecell body of another neuron or meetsanother cell

NeurotransmitterA chemicalsubstance thattransmits nerveimpulsesacross asynapse

Think, Share, Write #3What part of the cell sendselectrical signals?

Think, Share, Write #3What part of the cell sendselectrical signals?The part of the cell that sendselectrical signals is the axon.

Chapter 38 - Section 2:Neurons and the Nerve ImpulseNotesAdapted from Holt Biology 2008

Neurons and the Nerve ImpulseKey Point: Thenervous andendocrine systemshelp the bodymaintainhomeostasis byresponding tochange.

Neurons and the Nerve ImpulseImpulses in thenervous systemare electrical andchemical. Theelectrical signalsare caused by themovement of ionsacross the cellmembrane ofneurons.

YOUR TURN With a partner, read the Chapter 38Section 2 Active Reading – Neurons andNerve Impulses 1st - Take turns reading the questionsaloud to each other, alternating questions. 2nd - Take turns reading the selectionaloud to each other, alternating sentencesor paragraphs.Adapted from Holt Biology 2008

YOUR TURN As you read discuss the content. Reread and discuss each question. Writedown the best answer to the question usingfull descriptive sentences. Be prepared to share with the class.2Adapted from Holt Biology 2008Adapted from Holt Biology 2008

A NeuronThe NeuronSection 35-2NucleusAxon terminalsCell bodyMyelin sheathNodesAxonDendrites

The Nerve ImpulseKey Point: Animpulse beginswhen a neuron isstimulated byanother neuron orby a stimulus in itsenvironmentClick picture

Section 35-2The SynapseDirection of ImpulseDendrite ofadjacent neuronAxonReceptorVesicleAxonterminalSynaptic cleftNeurotransmitterSpace betweentwo neurons orneuron and muscleor gland.

Impulse - message crosses the synapsewith the aid of achemical called aneurotransmitter

Neurotransmitters change the permeability ofthe membrane of the next neuron, muscle orgland to allow moving impulse to go from oneto the otherclick

Think, Share, Write #4How are neurotransmittersreleased?

Think, Share, Write #4How are neurotransmittersreleased?Neurotransmitters are releasedfrom synaptic vesicles at thepresynaptic membrane byexocytosis.

Content ObjectivesWrite these down!I will be able to identify: How sensory information is detected. The five (5) types of sensoryreceptors. Where the sites of sensoryprocessing are in the brain.

Chapter 38 Section 3:Sensory SystemsKey VocabularyTermsAdapted from Holt Biology 2008

Sensory ReceptorA specializedstructure thatcontains the endsof sensoryneurons and thatresponds tospecific types ofstimuli

RetinaThe lightsensitive innerlayer of the eye,which receivesimages formed bythe lens andtransmits themthrough the opticnerve to the brain

CochleaA coiled tube thatis found in theinner ear and thatis essential tohearing

Semicircular CanalThe fluid-filledcanal in the innerear that helpsmaintain balanceand coordinatemovements

Taste BudOne of many ovalconcentrations ofsensory nerveendings on thetongue, palate,and pharynx

Think, Share, Write #5What types of cells are sensoryreceptors?

Think, Share, Write #5What types of cells are sensoryreceptors?The types of cells that are sensoryreceptors are specialized neuronslocated in sensory organs.

Chapter 38 - Section 3:Sensory SystemsNotesAdapted from Holt Biology 2008

Content ObjectivesWrite these down!I will be able to identify: How sensory information is detected. The five (5) types of sensoryreceptors. Where the sites of sensoryprocessing are in the brain.

The SensesSensory receptors:specialized neuronsthat react directly toenvironmentalstimuli

Key point: There are five generalcategories of sensory receptors:pain torsphotoreceptors

Pain receptorsRespond to tissue damage

ThermoreceptorsRespond to mild heat and cold

MechanoreceptorsRespond to pressure

ChemoreceptorsRespond to chemicals

PhotoreceptorsRespond to light

Figure 35-14 The EyeFour Senses - Vision - The EyeSection 35-4Vitreous humorMuscleLensFoveaAqueous humorCorneaPupilOptic nerveIrisBlood vesselsLigamentsRetinaChoroidSclera

Cornea - focuses light

Iris - colored part of the eye,contains muscles to control openingof the pupil

Pupil - allows light into the eye

Lens - adjusts focus, muscles controlshape of the lens

Retina - contains photo receptors (rods& cones) that convert light to nerveimpulses

Rods - sensitive to light, no colorsCones -distinguishes color

Optic nerve - carries impulses to the brain

YOUR TURN With a partner, read the Chapter 38Section 3 Active Reading – SensorySystems 1st - Take turns reading the questionsaloud to each other, alternating questions. 2nd - Take turns reading the selectionaloud to each other, alternating sentencesor paragraphs.Adapted from Holt Biology 2008

YOUR TURN As you read discuss the content. Reread and discuss each question. Writedown the best answer to the question usingfull descriptive sentences. Be prepared to share with the class.2Adapted from Holt Biology 2008Adapted from Holt Biology 2008

Figure 35-15 The EarSection 35-4OvalwindowAnvil StirrupSemicircular canalsHammerCochlear nerveCochleaBoneAuditory canalTympanumRound windowEustachian tube

Auditory canal -funnels sound into ear

Tympanic membrane - vibrates to furthertransmit sound