Chapter 6- Body and Behavior

Chapter 6- Body and Behavior1The Nervous SystemControls emotions, thinking, movements, and behaviorTwo PartsCentral Nervous System (CNS)- brain and spinal cordPeripheral Nervous System (PNS)- smaller nerves that reach other parts of the bodyAll parts are protected by sheathing and vertebrae (injury could lead to paralysis)2

3NeuronsLong, thin, cells of nerve tissue along which messages travel to and from the brainTransmission occurs when neurons are stimulated past a minimum point and emit a signalAll-or-none principle- neurons fire at full length only

4Basic Neuron PartsCell Body- Contains the nucleus and produces energyDendrites- receive impulses or messages from other neurons and send to cell body

5Basic Neuron PartsAxon- long fiber that carries impulses away from the cell body towards the dendrites of the next neuronMyelin Sheath- protects the axonAxon Terminals- opposite dendrite of another neuron

6Basic Neuron Parts

7The Neuron ConnectionSynapse- the space between the axon terminals of one neuron and the dendrites of another neuron

8The Neuron ConnectionA neuron transmits its impulses or message to another neuron across the synapse by releasing chemicals called neurotransmitters.Can either:Excite the next neuronStop it from transmitting (inhibit)Only allow flow in one direction

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10NeurotransmittersNeurotransmitterFunctionProblems Associated with an Excess or a DeficitAcetylcholineMotor MovementLack of acetylcholine is associated with Alzheimers diseaseDopamineMotor Movement and AlertnessLack of dopamine is associated with Parkinsons disease, an overabundance is associated with schizophreniaEndorphinsPain controlInvolved in addictionsSerotoninMood controlLack of serotonin is associated with clinical depression11NeurotransmittersNorepinephrine- involved with memory and learningEndorphins- inhibit pain- inside morphineToo much or too little is linked to certain diseasesUndersupply of acetylcholine (memory and movement)- Alzheimer's Oversupply of dopamine (learning, emotional arousal)- SchizophreniaUndersupply of dopamine- Parkinsons diseaseUndersupply of norepinephrine and serotonin- depression12Neuron ActivityIntensity of activity in each neuron depends on how many other neurons are acting on itEach individual neuron is eitherON or OFF depending onwhether most of the neuronsacting on it are either excitingor inhibiting

13Neuron ActivityAfferent neurons- relay messages from the sense organs to the brain

Efferent neurons- relay messages from brain to glands and muscles

Interneurons- carry impulses between neurons

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15Voluntary and Involuntary ActivitiesParts of the Peripheral Nervous Nervous SystemSomatic Nervous System (SNS)- voluntary activitiesAutonomic Nervous System (ANS)- involuntary activitiesSympathetic- prepares for emergencies or strenuous activityIncreases HR and BP, suspends digestionParasympathetic- conserves energy and enhances recovery from strenuous activityReduces HR and BP

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17The Nervous System18The Three Brains: HindbrainIncludes the Cerebellum- posture, balance, voluntary movementsMedulla- breathing, heart rate, reflexesPons- bridge between spinal cord and brain, also helps in sleep

19The Three Brains: MidbrainIntegrates sensory information and regulates it upwardBrain stem= medulla +pons +midbrainReticular Activating System- plays a role in the sleep cycle

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21The Three Brains: ForebrainThalamus- integrates sensory input (except smell)Hypothalamus- hunger, thirst, sexual behavior, changes in temp.Cerebral cortex- learning and storing information, projecting informationLimbic System- core of forebrain- includes above and:Amygdala- violent emotionsHippocampus- forming new memories

22The Lobes of the BrainThe cerebrum is two hemispheres connected by a band of fibers called the corpus collosumDivided into lobesOccipital- visualParietal- senses from all over the bodyTemporal- hearing, memory, speakingFrontal- organization, planning

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MotorAreaSensory Area

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25Left and Right HemispheresProperties of the two sides have been simplifiedComplement and help each otherEach side is connected to one half of the body in a criss-cross patternLeft side- speech, math, logic, understandingRight side- visual, spatial ability (puzzles), creativity, music

26Split Brain OperationsWhen people are prone to grand mal seizures, separating the brain hemispheres will make them more severeSide effects: seem normal but, if a man whose brain has been split holds a ball in his right hand, he will be able to say it is a ball, but in his left hand, he will not be able to say what it is. Information cannot cross to the speech center in the left hemisphere

27Studying the BrainRecording:Inserting electrodes (wires) into the brain- record activityEEG- can record activity of large portions of the brainRhythmic pattern that depends on whether a person is awake, drowsy, or asleep

28Studying the BrainStimulation- causing neurons to fireUse during brain surgery to find the malfunctioning partBy applying an electric currentto the temporal lobe, cantrigger memory sequencesOne woman believed that a radio was being played inthe operating room** Pain relief without drugs

29Studying the BrainLesions- cutting or destroying part of an animals brainDifference in behaviorsRemoving part of the temporal lobe of monkeys made them less fearful and violent- aggressionFar more complex than people thought at first

30Studying the BrainAccidents- Phineas GageRailroad foreman who had a 13 pound, three foot long iron bar go through his skull (1848)Survived, but suffered personality changes- was short tempered and said inappropriate thingsIn 1994, realized that damage had been done to the frontal cortex, which censors thoughts and ideas

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CT Scans: An x-ray of the brain.

A CT scan is essentially a computerized assembly of several x-ray images taken from a series of different angles. With a CT, the resolution is much better than conventional x-rays, and the detail that can be seen is much greater. **Can pinpoint brain injuries and deterioration32PET measures the emission of positrons from the brain after a small amount of radioactive isotopes, or tracers, have been injected into the blood stream. A common example is a glucose-relative with embedded fluor-18. With this molecule, the activity of different regions of the brain can be measured. The result is a three-dimentional map with the brain activity represented by colors.

PET

SCANS33 MRI is a noninvasive imaging technique that does not use x-rays. The process involves passing a strong magnetic field through the head. The magnetic field used is 30,000 + times that of the earth's magnetic field. It's effect on the body, however, is harmless and temporary. The MRI scanner can detect radiation from certain molecules, which are present in different concentrations in different tissues.

Tumor

34The Endocrine SystemA chemical communication system that uses hormones to send chemical messages through the bloodstreamProduced in the endocrine glandsSite specificReleased directly into the bloodstreamAffect growth, metabolic processes, determine gender, secreting during stress, influence mood and drives35

36The Pituitary GlandCenter of control of the endocrine system that secretes a large number of hormonesMonitored by the hypothalamus

37The Thyroid GlandProduces thyroxine- stimulates chemical reactions important for all tissuesToo little- lethargicToo much- overactivity

38Sex GlandsTestes and ovariesProduces testosterone, estrogen, and progesterone

39Hormones vs. NeurotransmittersThe same chemical (norepinephrine) can be used as bothNeurotransmitter- released right beside the cell it will excite or inhibitHormone- released into the blood and diffused without the body40Heredity and EnvironmentHeredity- the genetic transmission of characteristics from parents to offspringGenes- the basic units of heredity, can interact with environment to cause behaviorNature vs. NurtureGalton- success runs in familiesWatson- give me a dozen healthy infants and Ill guarantee to take any one at random and train him to be any specialist I might select

41Twin StudiesIdentical Twins- develop from a single fertilized egg (monozygotic) and share the same genesFraternal Twins- come from two different eggs fertilized by two different spermMinnesota Twin Study- share many common behaviors despite different social, cultural, and economic backgrounds

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