The Biology of Mind

CHAPTER OVERVIEW

Chapter 2 is concerned with the functions of the brainand its component neural systems, which provide thebasis for all human behavior. Under the direction ofthe brain, the nervous and endocrine systems coordi-nate a variety of voluntary and involuntary behaviorsand serve as the body's mechanisms for communica-tion with the extemal environment.

The brain consists of the brainstem, the thalamus,the cerebellum, the limbic system, and the cerebralcortex. Knowledge of the workings of the brain hasincreased with advances in neuroscientific methods.Studies of split-brain patients have also givenresearchers a great deal of information about the spe-cialized functions of the brain's right and left hemi-spheres.

Many students find the technical material in thischapter difficult to master. Not only are there manyterms for you to remember, but you must also knowthe organization and function of the various divisionsof the nervous system. Learning this material willrequire a great deal of rehearsal. Working the chapterreview several times, drawing and labeling brain dia-grams/ and mentally reciting terms are all useful tech-niques for rehearsing this type of material.

NOTE: Answer guidelines for all Chapter 2 questionsbegin on page52.

CHAPTER REVIEW

First, skim each section, noting headings and boldfaceitems. After you have read the section, review eachobjective by answering the fill-in and essay-typequestions that follow it. As you proceed, evaluateyour performance by consulting the answers begin-ning on page 52. Do not continue with the next sec-tion until you understand each answer. If you needto, review or reread the section in the textbook beforecontinuing.

lntroduction (pp. 47-48)

Objective 1: Explain why psychologists are con-cerned with human biology, and describe the ill-fatedphrenology theory.

L. In the most basic sense/ every idea, mood, memo-

ry, andbehavior that an individual has ever expe-

rienced is a phenomenon.

2. The theory that linked our mental abilities to

bumps on the skull was

J. Researchers who study the links between biology

and behavior are called

4. We are made up of smaller and smaller

; we are also part of larger

. Thus, we are

systems.

Neural Communication (pp. aa-sa)

Objective 2: Describe the parts of a neuron, andexplain how its impulses are generated.

1. Our body's neural system is built from billions of

nerve cells, or __ =-_=- . Information

arriving in the brain and spinal cord from the

body travels in -.=--.- neurons.

Instructions from the brain and spinal cord are

sent to the body's tissues via

neurons. The neurons that enable internal com-

munication within the brain are called

J/

38 Chapter 2 The Biology of Mind

2. The extensions of a neuron that receive messages 8. To trigger a neural impulse,

from other neurons are the signals minus

3. The extension of a neuron that transmits informa-exceed a certain intensity, called the

tion to other neurons is the. Increasing a stimulus above

this level (will/will not)some of these extensions are insulated by a fatty

increase the neural impulse's intensity. This phe-tissue called the

which helps speed the

neuron's impulses.

Identify the major parts of the neuron dia-

grammed below.

c.d.

5. The neural impulse, or

, is a brief electrical charge

that travels down a(n)

5. The fluid interior of a resting axon carries mostly

(positively / ne gatively)

charged ions, while the fluid outside has mostly

(positively /negatively)charged ions. This polarization, called the

occurs

because the cell membrane is

An action potential occurs when the first part of

the axon opens its gates and -(positively/negatively) charged ions rush in,

causing that part of the neuron to become

. During the resting pause

following an action potential, called the

neuron pumPs

(positively/negatively) charged ions back outside

the cell.

signals must

nomenon is called an

response.

9. The strength of a stimulus

(does/does not) affect the intensity of a neural

impulse. A strong stimulus

(can/cannot) trigger more neurons to fire.

Objective 3: Describe how nerve cells communicate.

10. The junction between two neurons is called a

, and the gap is called the

. This

discovery was made by

11. The chemical messengers that convey informa-

tion across the gaps between neurons are called

. These chemicals bind to

receptor sites and unlock tiny channels, allowing

4.

--a

a.

b.

electrically charged

the neuron.

to enter

12. Neurotransmitters influence neurons either by

their

readiness to fire. Excess neurotransmitters are

reabsorbed by the sending neuron in a process

called

Outline the sequence of reactions that occur when aneural impulse is generated and transmitted from oneneuron to another.

7.

the

M_i' ,4

Objective 4: Describe how neurotransmitters influ-ence behavior, and explain how drugs and otherchemicals affect neurotransmission.

1.3. A neurotransmitter that is important in muscle

sis by blocking the activity of the neurotransmit-ter ACh.

The Nervous System (pp. ss-s8)Objective 5: Identify the two major divisions of thenervous system, and describe their basic functions.

1. Taken altogether, the neurons of the body form

The Endocrine System

5. The body is made ready for action by thedivision of the autonomic

nervous system.

7. The division of the autonom-

ic nervous system produces relaxation.

Describe and explain the sequence of physicalreactions that occur in the body as an emergency isconfronted and then passes.

Beginning with the sensory receptors in the skin,trace the course of a spinal reflex as a person reflex-ively jerks his or her hand away from an unexpected-ly hot burner on a stove.

The Endocrine System (pp. sB-60)Objective 6: Describe the nature and functions of theendocrine system and its interaction with the nervoussystem.

L. The body's chemical communication network is

called the

This system transmits information through chem-ical messengers called

at a much (faster/slower)

rate than the nervous system, and its effects last

39

14.

contraction is ; it is alsoimportant in learning and

Naturally occurring opiatelike neurotransmittersthat are present in the brain are called

. When the brain is floodedwith drugs such as or

it may stop producing theseneurotransmitters.

15. Drugs that produce their effects by mimicking 8. Neurons cluster into work groups calledneurotransmitters are called

Drugs that block the effects of neurotransmittersby occupvins their

9. Automatic responses to stimuli, called

illustrate the work of theare called

. Simple\Alhile certain drugs create a pathways such as these are involved in thetemporary "high" by mimicking the endorphins,

the poison produces paraly- response and in the reflex.

the

2. The brain and spinal cord form the

nervous system. Theneurons that link the brain and spinal cord to the

body's sense receptors, muscles, and glands form

nervous system.

J. Sensory and motor axons are bundled into electri-

cal cables called

4. The division of the peripheral nervous system

that enables voluntary control of the skeletal

muscles is thenervous system.

5. Involuntary, self-regulating responses-those ofthe glands and muscles of internal organs-arer:ontrolled by the

system.

the

nervous

time).

(a longer time/a shorter

40

2.

Chapter 2 The Biology of Mind

ln a moment of danger, the autonomic nervous

system orders the

release

J. By comparing scans taken less than a second

glands to apart. the

detects oxygen-laden bloodflow to the part of the

brain thought to control the bodily activity being

studied. Using this technique, researchers found

that bloodflow to the back of the brain(increases / decreases) when

people view a scene because that is where

information is processed.

Objective 8: Describe the components of the brain-stem, and summarize the functions of the brainstem,thalamus. and cerebellum.

6.

|7

The oldest and innermost region of the brain is

the

At the base of the brainstem, where the spinal

cord enters the skull, lies the

, which controls

and

Just above this part is the

which helps coordinate movements.

Nerves from each side of the brain cross over to

connect with the body's opposite side in the

9. The finger-shaped network of neurons, the

/ 1S COn-

tained inside the brainstem and plays an impor-

tant role in controllins

Electrically stimulating this area will produce an

animal. Lesioning this area

to lapse into a

10. At the top of the brainstem sits the

which serves as the brain's

sensory switchboard, receiving information from

all the senses except and

routing it to the regions dealing with those

senses. These egg-shaped structures also receive

replies from the higher regions, which they direct

and

3. The most influential gland is the

, which, under the control ofan adjacent brain area called the

, helps regulate

and the release of hormonesby other endocrine glands.

Write a paragraph describing the feedback systemthat links the nervous and endocrine systems.

The Brain (pp. 6o-s t)Obiective 7: Describe several techniques for studyingthe brain.

1. Researchers sometimes study brain function by

producing or bv selectivelv

destroying brain cells. The oldest technique for

studying the brain involves

of patients with brain

injuries or diseases.

2. The is an amplified record-

ing of the waves of electrical activity that sweepacross the brain's surface.

3. The technique depicting the level of activity ofbrain areas by measuring the brain's consump-tion of glucose is called the

Briefly explain the purpose of the PET scan.

A technique that produces clearer images of the

brain (and other body parts) by using magnetic

fields and radio waves is known as

will cause an animal

to the and to the

LL. At the rear of the brainstem lies the

. It influences one type of

and

memory. It also coordinates voluntary movement

and control.

12. The lower brain functions occur without

effort, indicating that our

brains process most information

(inside/outside) of our awareness.

Objective 9: Describe the structures and functions ofthe limbic system, and explain how one of thesestructures controls the pituitary gland.

13. Between the brainstem and cerebral hemispheres

16. Below the thalamus is the

ulates behavior by secreting

that enable it to control the

gland. Olds and Milner discovered that this

region also contains centers,

which animals will work hard to have stimulated.

Some researchers believe that alcohol depen-

dence, drug abuse, binge eating, and other

disorders may stem from a

genetic

in the natural brain systems for pleasure and

well-being.

The Brain 4'1,

Objective L0: Describe the structure of the cerebralcortex, and explain the various functions of the fourlobes.

18. The most complex functions of human behavior

are linked to the most developed part of the

brain, the

This thin layer of interconnected neural cells is

the body's ultimate control and

center.

19. The cells that support, protect, and nourish corti-

cal neurons are called

c.

d.

needed, the (smaller/

greater) amount of cortical space occupied.

Findings from clinical trials involving

tn

which, for example, recording electrodes were

implanted in this area of a 2S-year-old man's

brain, raise hopes that people who are

may one day be able to con-

These cells may also play a

role in and - .is the system. One

component of this system that processes memory 20. Compared to the cortexes of lower mammals, the

is the -human cortex has a

14. Aggression or fear will result from stimulation of

different regions of the lima bean-sized neural

(smoother/more wrinkled) surface. This

(increases/decreases) the

clusters, theoverall surface area of our brains.

21. List the four lobes of the brain.1,5. We must remember, however, that the brain

(islis not) neatly organized a.

b.into structures that correspond to our categories

of behavior. For example, aggressive behavior

(does/does not) involveObjective 11: Summarize some of the findings on thefunctions of the motor cortex and the sensory cortex,and discuss the importance of the association areas.

22. Eleckical stimulation of one side of the

neural activity in many brain levels.

which regulates bodily maintenance behaviors cortex, an arch-shapedsuch as region at the back of the

and lobe, will produce movement on the opposite

side of the body. The more precise the controlbehavior. This area also reg-

17.

trol machines directly with their

24.

42 Chapter 2 The Biology of Mind

23. At the front of the parietal lobes lies the

cortex, which, when stimu-

lated, elicits a sensation of

The more sensitive a body region, the greater the

area of

devoted to it.

25. Visual information is received in the

lobes, whereas auditory

information is received in the

lobes.

Areas of the brain that don't receive sensory

information or direct movement but, rather, inte-

grate and interpret information received by other

regions are known as __

. Approximately

of the human cortex is of thistype. Such areas in theare involved in judging, planning, and processing

of new memories and in some aspects of person-

ality. In the lobe, these areas

enable mathematical and spatial reasoning, and

an area of the Iobe enables us

to recognize faces.

27. Although the mind's subsystems are localized in

particular brain regions, the brain

(does/does not) act as a

unified whole.

Objective 12: Discuss the brain's plasticity followinginjury or illness.

28. The quality of the brain that makes it possible for

undamaged brain areas to take over the functions

of damaged regions is known as

damaged brain is called

(can/cannot) generate new

brain cells through a process called

Research also reveals the

existence of master cells in

the human embryo that can develop into any

type of brain cell.

Objective 13: Describe split-brain research, andexplain how it helps us understand the functions ofour left and right hemispheres.

30. The brain's two sides serve differing functions,

which is referred to as hemispheric specialization,

. Because damage to it

will impair language and understanding, the

hemisphere came to be

known as the hemisphere.

In treating several patients with severe epilepsy,Vogel and Bogen separated the two hemispheresof the brain by cutting the

. When this structure is sev-ered, the result is referred to as a

32. ln a split-brain patient, only thehemisphere will be aware of

an unseen object held in the left hand. In this

case, the person would not be able to

the object. When different

words are shown in the left and right visual

fields, if the patient fixates on a point on the cen-

ter line between the fields, the patient will be able

to sav onlv the word shown on the

26.

31.lobe

. This quality is especially

Explain why a split-brain patient would be able toread aloud the word pencil flashed to his or her rightvisual field, but would be unable to identify apencilby touch using only the left hand.apparent in the brains of

(young children / adolescents / adults).

29. Although severed neurons usually

(will/will not) regenerate, some neural tissue can

in response to damage. The

form of therapy aimed at helping to reprogram a33. When the "two minds" of a split brain are at

odds, the hemisphere tries totherapy. New evidence sug- rationalize what it doesn't understand. The

gests that adult mice and humans hemisphere often acts on

autopilot. This phenomenon demonstrates thatthe mind(can/cannot) control our behavior.

34. Deaf people use the hemi-

sphere to process sign language.

35. Although the hemisphere is 4.better at making literal interpretations of lan-

guage, the hemisphere excels

at quick, intuitive responses and at copying

drawings,

perceiving objects, and perceiving

Objective 14: Discuss research findings on brainorganization and handedness.

36. In all cultures of the world, most of the humanpopulation is (right/left)-

handed. Genetic factors

(play / do not play) a role in handedness. This

handedness bias is unique to humans and to ournearest relatives.

PROGRESS TEST I

Multiple- Cho ice Que stions

Circle your answers to the following questions andcheck them with the answers beginning on page 53. Ifyour answer is incorrect, read the explanation forwhy it is incorrect and then consult the appropriatepages of the text (in parentheses following the correctanswer).

1. The axons of certain neurons are covered by alayer of fatty tissue that helps speed neural trans-mission. This tissue isa. dopamine.b. the myelin sheath.c. acetylcholine.d. an endorphin.

2. Heartbeat, digestion, and other self-regulatingbodily functions are governed by thea. voluntary nervous system.b. autonomic nervous system.c. sympathetic division of the autonomic ner-

vous system.d. somatic nervous system.

Progress Test 1

3. A strong stimulus can increase the

speed of the impulse the neuron fires.intensity of the impulse the neuron fires.number of times the neuron fires.threshold that must be reached before theneuron fires.

The pain of heroin withdrawal may be attribut-able to the fact that

under the influence of heroin the brain ceasesproduction of endorphins.under the influence of heroin the brain ceasesproduction of all neurotransmitters.during heroin withdrawal the brain's produc-tion of all neurotransmitters is greatlyincreased.heroin destroys endorphin receptors in thebrain.

The brain research technique that involves moni-toring the brain's usage of glucose is called (inabbreviated form) thea. PET scan.b. fMRI.

c. EEG.d. MRI.

The effect of a drug that is an antagonist is toa. cause the brain to stop producing certain

neurotransmitters.b. mimic a particular neurotransmitter.c. block a particular neurotransmitter.d. disrupt a neuron's all-or-none firing pattern.

Though there is no single "control center" foremotions, their regulation is primarily attributedto the brain region known as thea. limbic system. c. brainstem.b. reticular formation. d. cerebellum.

Which is the correct sequence in the transmissionof a simple reflex?a. sensory neuron/ interneuron/ sensory neuronb. interneuron, motor neuron, sensory

neuronc. sensory neuron/ interneuron, motor

neurond. interneuron, sensory neuron, motor

neuron

43

b.c.d.

b.

c.

d.

5.

6.

1

8.

15.

44

9.

Chapter 2 The Biology of Mind

In a resting state, the axon isa. depolarized, with mostly negatively charged

ions outside and positively charged ionsinside.

b. depolarized, withmostly positively chargedions outside and negatively charged ionsinside.

c. polarized, with mostly negatively chargedions outside and positively charged ionsinside.

d. polarized, with mostly positively charged ionsoutside and negatively charged ions inside.

Which of the following is typically controlled bythe right hemisphere?a. languageb. learned voluntary movementsc. arithmeticreasoningd. perceptual tasks

Dr. Hernandez is studying neurotransmitter ab-normalities in depressed patients. She wouldmost likely describe herself as aa. personalitypsychologist.b. phrenologist.c. psychoanalyst.d. biological psychologist.

The increasing complexity of animals'behavior isaccompanied by ana. increase in the size of the brainstem.b. increase in the depth of the corpus callosum.c. increase in the size of the frontal lobes.d. increase in the amount of association area.

Voluntary movements, such as writing with apencil, are directed by thea. sympathetic nervous system.b. somatic nervous system.c. parasympatheticnervoussystem.d. autonomic nervous system.

A neuron will generate action potentials when ita. remains below its threshold.b. receives an excitatory input.c. receives more excitatory than inhibitory

inputs,d. is stimulated bv a neurotransmitter.

\A/hich is the correct sequence in the transmissionof a neural impulse?a. axon, dendrite, cellbody, synapseb. dendrite, axon/ cellbody, synapsec. synapse, axon, dendrite, cellbodyd. dendrite, cellbody, axon, synapse

Chemical messengers produced by endocrineglands are called

a. agonists.b. neurotransmitters.

c. hormones.d. enzymes.

Following a head injury, a person has ongoingdifficulties staying awake. Most likely, the dam-age occurred to thea. thalamus. c. reticular formation.b. corpus callosum. d. cerebellum.

An experimenter flashes the word FLYTRAP ontoa screen facing a split-brain patient so that FLYprojects to her right hemisphere and TRAP to herleft hemisphere. When asked what she saw, thepatient willa. say she saw FLY.b. say she saw TRAP.c. point to FLY using her right hand.d. point to TRAP using her left hand.

Cortical areas that are not primarily concernedwith sensory, motor, or language functions area. called projection areas.b. called association areas.c. located mostly in the parietal lobe.d. located mostly in the temporal lobe.

In the brain, learning occurs as experiencestrengthens certain connections in cell workgroups calleda. action potentials.b. neural networks.

c. endocrine systems.d. dendrites.

1,0.

16,

17.

1.8.

19.12.

20.13.

L1.

14.

Matching Items

Match each structure or technique with its corre-sponding function or description.

Structures

1. hypothalamus2. lesion

Progress Test 2 45

Functions or Descriptions

amplified recording of brain wavestechnique that uses radio waves and magneticfields to image brain anatomyserves as sensory switchboardcontains reward centerstissue destructiontechnique that uses radio waves and magneticfields to show brain functionhelps control arousallinks the cerebral hemispheresinfluences rage and fearregulates breathing and heartbeatenables coordinated movement

Melissa has just completed running a marathon.She is so elated that she feels little fatigue or dis-comfort. Her lack of pain is probably the result ofthe release ofa. ACh.b. endorphins.

a.

b.EEGfMRIreticular formationMRIthalamuscorpus callosumcerebellumamygdalamedulla

PROGRESS TEST 2

Progress Test 2 should be completed during a finalchapter review. Answer the following questions afteryou thoroughly understand the correct answers forthe section reviews and Progress Test 1.

Multiple- Choice Questions

1. The visual cortex is located in thea. occipital lobe. c. frontal lobe.b. temporal lobe. d. parietal lobe.

2. Which of the following is typically controlled bythe left hemisphere?

a. spatial reasoningb. word recognitionc. the left side of the bodyd. perceptual skills

3. When Sandy scalded her toe in a tub of hot water,the pain message was carried to her spinal cordby the

In the brain, I outnumber neurons. I also providenutrients to the neurons and help remove excessneurotransmitters. I am a

a. hormone.b. myelin sheath.c. glial cell.d. gland.

The technique that uses magnetic fields and radiowaves to produce computer images of structureswithin the brain is called

J.

4.J.

5.n

8.9.

10.11.

c.d.e.f.

g.h.i.j .k.

1

8.

a. the EEG.b. a lesion.

c. dopamine.d. norepinephrine.

c. a PET scan.d. MRI.

a, somaticb. sympathetic

nervous system.c. parasympatheticd. central

The myelin sheath that is on some neuronsa. increases the speed of neural transmission.b. slows neural transmission.c. regulates the release of neurotransmitters.d. prevents positive ions from passing through

the membrane.4. Which of the following are governed by the sim-plest neural pathways?

a. emotionsb. physiological drives, such as hungerc. reflexesd. movements, such as walking

MatchingltemsMatch each structure or term with its correspondingfunction or description.

Structures or Terms

L. right hemisphere2. brainstem

temporal lobesoccipital lobesplasticityneurogenesisreuptakelimbic systemassociation areasleft hemisphereglial cells

In the diagrams to the right, the numbers refer tobrain locations that have been damaged. Match eachlocation with its probable effect on behavior.

Location

Behaztioral Effect

a. vision disorderb. insensitivity to touchc. motor paralysisd. hearing probleme. lack of coordinationf. abnormal hungerg. split brainh. sleep/arousal

disorder

Progress Test 2 47

Functi on s or D es cipti ons

the formation of new neuronsspecializes in rationalizing reactionssupport cells of the nervous systemspecializes in spatial relations

e. brain areas containing the auditory cortexf. brain areas containing the visual cortexg. oldest part of the brainh. regulates emotioni. the brain's capacity for modificationj. absorption of excess neurotransmittersk. brain areas involved in higher mental functions

a.b.c.d.

J.

4.5.

6.Fl

8.9.

1.0.l't.

1..,J.

4.5.

6.n

8.