Chapter 2 Chapter 2 Biology and BehaviorBiology and Behavior

Chapter 2 OverviewChapter 2 Overview

The Neurons and NeurotransmittersThe Neurons and Neurotransmitters The Human Nervous SystemThe Human Nervous System Discovering the Brain’s MysteriesDiscovering the Brain’s Mysteries A Closer Look at the BrainA Closer Look at the Brain Age and Gender Differences in the Age and Gender Differences in the

BrainBrain The Endocrine SystemThe Endocrine System Genes and Behavioral GeneticsGenes and Behavioral Genetics

What are the functions of What are the functions of the various parts of the the various parts of the neuron?neuron?

Cell bodyCell body– Carries out life-Carries out life-

sustaining functionssustaining functions DendritesDendrites

– Receive signals from Receive signals from other neuronsother neurons

AxonAxon– Sends signals to other Sends signals to other

neurons, muscles, and neurons, muscles, and glandsglands

SynapseSynapse– Junction between Junction between

neuronsneurons

What are What are neurotransmitters?neurotransmitters?

NeurotransmittersNeurotransmitters are chemical are chemical substances that substances that transmit messages transmit messages between neuronsbetween neurons– Released into synapse Released into synapse

by axon terminals of by axon terminals of sending neuronsending neuron

– Bind to receptor sites on Bind to receptor sites on dendrites of receiving dendrites of receiving neuronneuron

– Taken back into axon Taken back into axon terminal by the process terminal by the process of of reuptakereuptake

What are the functions of What are the functions of some major some major neurotransmitters?neurotransmitters? AcetylcholineAcetylcholine

– Affects movement, learning, memory, REM SleepAffects movement, learning, memory, REM Sleep

DopamineDopamine– Affects movement, attention, learning, Affects movement, attention, learning,

reinforcement, pleasurereinforcement, pleasure

NorepinephrineNorepinephrine– Affects eating, alertness, wakefulnessAffects eating, alertness, wakefulness

EpinephrineEpinephrine– Affects metabolism of glucose, energy release Affects metabolism of glucose, energy release

during exerciseduring exercise

What are the functions of What are the functions of some major some major neurotransmitters?neurotransmitters? SerotoninSerotonin

– Affects mood, sleep, appetite, impulsivity, aggressionAffects mood, sleep, appetite, impulsivity, aggression

GlutamateGlutamate– Active in areas of the brain involved in learning, Active in areas of the brain involved in learning,

thought, and emotionthought, and emotion

GABAGABA– Facilitates neural inhibition in the central nervous Facilitates neural inhibition in the central nervous

systemsystem

EndorphinsEndorphins– Provide relief from pain and produce feelings of Provide relief from pain and produce feelings of

pleasure and well-beingpleasure and well-being

The Human Nervous The Human Nervous SystemSystem Central nervous systemCentral nervous system

– The brain and spinal cordThe brain and spinal cord Peripheral nervous systemPeripheral nervous system

– The nerves connecting the central The nerves connecting the central nervous system to the rest of the nervous system to the rest of the bodybody

Which brain structures are Which brain structures are found in the hindbrain?found in the hindbrain?

MedullaMedulla– Controls heartbeat, Controls heartbeat,

blood pressure, blood pressure, breathing, coughing, breathing, coughing, swallowingswallowing

Reticular formationReticular formation– Plays a crucial role in Plays a crucial role in

arousal and attentionarousal and attention– Screens sensory Screens sensory

messages entering the messages entering the brainbrain

Which brain structures are Which brain structures are found in the hindbrain?found in the hindbrain?

PonsPons– Plays a role in body Plays a role in body

movementmovement– Influences sleep and Influences sleep and

dreamingdreaming CerebellumCerebellum

– Helps the body execute Helps the body execute smooth, skilled smooth, skilled movementsmovements

– Regulates muscle tone Regulates muscle tone and postureand posture

What important structure is What important structure is located in the midbrain?located in the midbrain?

The midbrain links the physiological functions of the hindbrain to the cognitive functions of the forebrain

Substantia nigra– Controls

unconscious motor movements

Which brain structures and Which brain structures and functions are found in the functions are found in the forebrain?forebrain? ThalamusThalamus

– A relay station for A relay station for information flowing information flowing into or out of the braininto or out of the brain

HypothalamusHypothalamus– Regulates hunger, Regulates hunger,

thirst, sexual behavior, thirst, sexual behavior, body temperature, and body temperature, and a wide variety of a wide variety of emotional behaviorsemotional behaviors

Which brain structures and Which brain structures and functions are found in the functions are found in the forebrain?forebrain? AmygdalaAmygdala

– Structure in the Structure in the limbic limbic system system that plays an that plays an important role in emotionimportant role in emotion

HippocampusHippocampus– Structure in the Structure in the limbic limbic

system system that plays a that plays a central role in storing central role in storing new memories, new memories, responses to new or responses to new or unexpected stimuli, and unexpected stimuli, and navigational abilitynavigational ability

The Peripheral Nervous The Peripheral Nervous SystemSystem

The The peripheral nervous systemperipheral nervous system has two subdivisionshas two subdivisions– The The somatic nervous systemsomatic nervous system consists consists

of all sensory nerves and motor nerves of all sensory nerves and motor nerves – The The autonomic nervous systemautonomic nervous system

transmits messages between the transmits messages between the central nervous system and the glands, central nervous system and the glands, the cardiac muscle, and the smooth the cardiac muscle, and the smooth musclesmuscles

Two parts of the Two parts of the autonomic nervous autonomic nervous systemsystem Sympathetic nervous systemSympathetic nervous system

– Mobilizes the body’s resources Mobilizes the body’s resources during stress and emergenciesduring stress and emergencies

Parasympathetic nervous Parasympathetic nervous systemsystem– Brings the heightened bodily Brings the heightened bodily

responses back to normal following responses back to normal following an emergencyan emergency

What is the difference between What is the difference between the sympathetic and the sympathetic and parasympathetic nervous parasympathetic nervous systems?systems?

Discovering the Discovering the Brain’s MysteriesBrain’s Mysteries Modern researchers do not have Modern researchers do not have

to wait to perform autopsies or to wait to perform autopsies or wait for injuries to occur to learn wait for injuries to occur to learn about the brainabout the brain

Today, researchers unlock the Today, researchers unlock the mysteries of the brain using a mysteries of the brain using a variety of techniquesvariety of techniques

What does the EEG reveal What does the EEG reveal about the brain?about the brain?

Electroencephalogram (EEG)Electroencephalogram (EEG) – A record of brain-wave activity made A record of brain-wave activity made

by a machine called an by a machine called an electroencephalographelectroencephalograph

– Electrical activity in the brain is Electrical activity in the brain is detected by electrodes placed on detected by electrodes placed on the scalpthe scalp

How are imaging techniques How are imaging techniques helpful in the study of brain helpful in the study of brain structure and function?structure and function? CT scan CT scan

– Computerized axial tomographyComputerized axial tomography– Uses X-rays to produce cross-Uses X-rays to produce cross-

sectional images of the brainsectional images of the brain MRIMRI

– Magnetic resonance imagingMagnetic resonance imaging– Produces high-resolution images of Produces high-resolution images of

the structures of the brainthe structures of the brain

How are imaging techniques How are imaging techniques helpful in the study of brain helpful in the study of brain structure and function?structure and function? PET scan PET scan

– Positron-emission tomographyPositron-emission tomography– Reveals activity in various parts of the Reveals activity in various parts of the

brain based on blood flow, oxygen use, brain based on blood flow, oxygen use, and glucose consumptionand glucose consumption

Functional MRI (fMRI)Functional MRI (fMRI)– Provides images of both brain structure Provides images of both brain structure

and functionand function– Can identify locations of brain activity Can identify locations of brain activity

more precisely and rapidly than PET scanmore precisely and rapidly than PET scan

A Closer Look at the A Closer Look at the BrainBrain The The cerebrumcerebrum

– The largest structure in the human The largest structure in the human brainbrain

– Its functions include language, Its functions include language, planning, and logicplanning, and logic

What are the components of What are the components of the cerebrum?the cerebrum?

Cerebral Cerebral hemisphereshemispheres– The left and right The left and right

halves of the cerebrumhalves of the cerebrum Corpus callosumCorpus callosum

– Connects the two Connects the two hemisphereshemispheres

Cerebral cortexCerebral cortex– Thin outer covering of Thin outer covering of

cerebrumcerebrum– Responsible for higher Responsible for higher

mental processes of mental processes of language, memory, and language, memory, and thinkingthinking

What are the specialized What are the specialized functions of the left and functions of the left and right hemispheres?right hemispheres? The The left left

hemispherehemisphere– Controls the right Controls the right

side of the bodyside of the body– Handles most Handles most

language language functionsfunctions

– Is specialized for Is specialized for mathematics and mathematics and logiclogic

What are the specialized What are the specialized functions of the left and functions of the left and right hemispheres?right hemispheres? The The right right

hemispherehemisphere– Controls the left side Controls the left side

of the bodyof the body– Processes musicProcesses music– Interprets emotional Interprets emotional

messages conveyed messages conveyed by tone of voice and by tone of voice and gesturesgestures

– Is specialized for Is specialized for visual-spatial visual-spatial relationsrelations

Which psychological Which psychological functions are associated functions are associated with the frontal lobes?with the frontal lobes? Motor cortexMotor cortex

– Area that controls Area that controls voluntary body voluntary body movementmovement

Broca’s areaBroca’s area– Area in the frontal Area in the frontal

lobe, usually in the lobe, usually in the left hemisphere, left hemisphere, that controls the that controls the production of production of speechspeech

Association areasAssociation areas– Areas involved in Areas involved in

thinking, planning thinking, planning for the future, for the future, impulse controlimpulse control

What important structure is What important structure is found in the parietal lobes?found in the parietal lobes? SomatosensorSomatosensor

y cortexy cortex– Strip of tissue at Strip of tissue at

the front of the the front of the parietal lobes parietal lobes where touch, where touch, pressure, pressure, temperature, temperature, and pain and pain register in the register in the cortexcortex

Why are the occipital lobes Why are the occipital lobes critical to vision?critical to vision?

The The occipital occipital lobeslobes are involved are involved in the reception and in the reception and interpretation of interpretation of visual informationvisual information

Primary visual Primary visual cortexcortex– Area at the rear of Area at the rear of

the occipital lobes the occipital lobes where vision where vision registers in the registers in the cortexcortex

What are the major areas What are the major areas within the temporal lobes, within the temporal lobes, and what are their and what are their functions?functions? Primary auditory Primary auditory

cortexcortex– Area in each Area in each

temporal lobe temporal lobe where hearing where hearing registers in the registers in the cortexcortex

Wernicke’s areaWernicke’s area– Language area in Language area in

the left temporal the left temporal lobe involved in lobe involved in comprehending comprehending spoken language spoken language and formulating and formulating coherent speech coherent speech and written and written languagelanguage

Age and Gender Age and Gender Differences in the Differences in the BrainBrain The brain grows from conception The brain grows from conception

until well into adulthooduntil well into adulthood Throughout development, the Throughout development, the

brains of males and females differ brains of males and females differ to some degreeto some degree

How do the brains of men How do the brains of men differ from those of women?differ from those of women?

Women’s brains have equal proportions of gray and Women’s brains have equal proportions of gray and white matter in the left and right hemispheres; men’s white matter in the left and right hemispheres; men’s brains have a lower proportion of white matter in the brains have a lower proportion of white matter in the left hemisphere than in the rightleft hemisphere than in the right– This may explain men’s superior ability in spatial tasksThis may explain men’s superior ability in spatial tasks

Women have more gray matter in the area of the Women have more gray matter in the area of the brain that controls emotionsbrain that controls emotions– This may explain women’s superior ability to perceive This may explain women’s superior ability to perceive

emotionsemotions Navigational information is processed in different Navigational information is processed in different

parts of the brain in men and womenparts of the brain in men and women– Women use right parietal cortex and right frontal cortexWomen use right parietal cortex and right frontal cortex– Men use left hippocampusMen use left hippocampus– Men and women use different areas to process location Men and women use different areas to process location

of soundof sound More research is needed to understand the meaning More research is needed to understand the meaning

of these gender differences in the brainof these gender differences in the brain

The Endocrine SystemThe Endocrine System

A system of ductless glands that A system of ductless glands that manufacture hormones and manufacture hormones and secrete them into the secrete them into the bloodstreambloodstream

What functions are What functions are associated with the various associated with the various glands of the endocrine glands of the endocrine system?system? Pituitary glandPituitary gland

– The “master gland”The “master gland”– Located in the brain Located in the brain – Releases hormones that activate other endocrine Releases hormones that activate other endocrine

glandsglands Pineal glandPineal gland

– Located deep in the brainLocated deep in the brain– Secretes the hormone Secretes the hormone melatoninmelatonin which controls which controls

sleep/wakefulness cyclesleep/wakefulness cycle Thyroid glandThyroid gland

– Located below the voice box Located below the voice box – Produces Produces thyroxinethyroxine, which regulates rate at which , which regulates rate at which

food is metabolizedfood is metabolized

What functions are What functions are associated with the various associated with the various glands of the endocrine glands of the endocrine system?system? Parathyroid glandsParathyroid glands

– Attached to the thyroidAttached to the thyroid– Produce Produce parathyroid hormoneparathyroid hormone which helps the which helps the

body absorb minerals from the dietbody absorb minerals from the diet Thymus glandThymus gland

– Produces hormones that are essential to immune Produces hormones that are essential to immune system functioningsystem functioning

Adrenal glandsAdrenal glands– Release hormones that prepare the body for Release hormones that prepare the body for

emergencies and stressful situationsemergencies and stressful situations GonadsGonads

– The ovaries in females and testes in malesThe ovaries in females and testes in males– Produce sex hormonesProduce sex hormones

Genes and Behavioral Genes and Behavioral GeneticsGenetics

GenesGenes– segments of DNA located on chromosomes segments of DNA located on chromosomes

that transmit all heredity traitsthat transmit all heredity traits ChromosomesChromosomes

– rod shaped structures in the nuclei of cells rod shaped structures in the nuclei of cells that contain all genes and carry genetic that contain all genes and carry genetic information to make a human beinginformation to make a human being

Behavioral GeneticsBehavioral Genetics– a field of research that uses twin and a field of research that uses twin and

adoption studies to investigate the relative adoption studies to investigate the relative effects of heredity and environment on effects of heredity and environment on behaviorbehavior

What patterns of What patterns of inheritance are evident in inheritance are evident in the transmission of genetic the transmission of genetic traits?traits? Dominant-recessive patternDominant-recessive pattern

– a set of inheritance rules in which one a set of inheritance rules in which one dominant gene causes a trait to be dominant gene causes a trait to be expressed, but two recessive genes are expressed, but two recessive genes are required for expression of a recessive trait required for expression of a recessive trait

Multifactorial inheritanceMultifactorial inheritance– A pattern of inheritance in which a trait is A pattern of inheritance in which a trait is

influenced by both genes and environmentinfluenced by both genes and environment Sex-linked inheritanceSex-linked inheritance

– Involves genes on the X and Y Involves genes on the X and Y chromosomeschromosomes

– Example: red-green color blindnessExample: red-green color blindness

Ishihara TestIshihara Test

What kinds of studies are What kinds of studies are done by behavioral done by behavioral geneticists?geneticists? Twin studiesTwin studies

– Examine identical (monozygotic) and Examine identical (monozygotic) and fraternal (dizygotic) twinsfraternal (dizygotic) twins

– If identical twins are more alike on a trait, If identical twins are more alike on a trait, the trait is assumed to be more influenced the trait is assumed to be more influenced by heredityby heredity

– If identical and fraternal twin pairs do not If identical and fraternal twin pairs do not differ on a trait, the trait is assumed to be differ on a trait, the trait is assumed to be more influenced by environmentmore influenced by environment

Adoption studiesAdoption studies– Compare adopted children’s abilities and Compare adopted children’s abilities and

traits to those of adoptive parents and traits to those of adoptive parents and biological parentsbiological parents