CHAPTER 3
BIOLOGY AND BEHAVIOR
Section 1: The Nervous System
Section 2: The Brain: Our Control Center
Section 3: The Endocrine System
Section 4: Heredity: Our Genetic Background
1
Chapter 3:Section 1
The Nervous System
Chapter 3
2
Main Objective:
 Explain how messages are
transmitted by neurons and describe
the functions of the peripheral
nervous system.
Chapter 3
3
What does the Nervous System do???
 Thinking
 Feeling
 Moving
 Dreaming
 Regulates internal functions
 Learning/memory
 Etc….
Chapter 3
4
Consists of 2 main parts:
1. Central Nervous System:
• Brain and spinal cord
2. Peripheral Nervous System:
* made up of nerve cells that send messages
between the central nervous system and all the
parts of the body.
Chapter 3
5
Neurons:
 Neurons:
 A nerve cell; the basic building
block of the nervous system.
 Each of us has more than
100 billion neurons!!!
Chapter 3
6
Components of a Neuron:
 Cell Body: Produces energy that fuels the activity
of the cell.
 Dendrites: Receive information from other neurons
and pass the message through the cell body
 Axon: Carries messages away.
Chapter 3
7
Components of Neuron (cont’d)
 Myelin sheath:
 A white, fatty substance that
insulates axons and enables rapid
transmission of neural impulses.
 Axon terminals:
 Small fibers branching out from an axon.
Chapter 3
8
The Communication Process:
 Messages are sent from the axon terminals of
one neuron to the dendrites of other neurons.
 In order for a message to be sent from one
neuron to another neuron, it must cross the
synapse
 A junction between the axon terminals of one neuron
and the dendrites of another neuron.
 Less than a millionth of an inch wide!
Chapter 3
9
Anatomy of 2 Neurons:
Chapter 3
10
Communication (cont’d)
 Messages are received by the dendrites and
travel through the cell body and the axon to the
axon terminals.
 They cross synapses to the dendrites of other
neurons
 New synapses can develop between neurons
that were not previously connected, as when we
learn something new!!
Chapter 3
11
Neurotransmitters: Chemical
Messengers
 Neurons send messages across synapses
through the release of neurotransmitters.
 Chemicals that are stored in sacs in the axon terminals.
 100’s can be fired
every second!!
Chapter 3
12
Neurotransmitters (cont’d)
 The message is converted into an electrical
impulse that travels the length of the neuron.
 The message is then transmitted to the next
neuron by neurotransmitters
 This whole process takes only a fraction of a
second!!!
Chapter 3
13
Different Types of
Neurotransmitters!
 Acetylcholine (Ach): control of muscles.
 Plays a part in Alzheimer’s disease
 Dopamine: motor behavior
 Deficiency plays a role in Parkinson's disease
 Serotonin: emotional arousal and sleep
Chapter 3
14
Section 1: The Nervous System
OVERVIEW OF MESSAGE
TRANSMISSION VIA NEURONS
 Messages are sent from the axon terminals of one
neuron to the dendrites of other neurons
 Messages travel in one direction and are received
by the dendrites and travel through the cell body
and the axon to the axon terminals.
 From there messages cross synapses to the
dendrites of other neurons.
Chapter 3
15
Hmmm…What do you think???
Endorphins are neurotransmitters that NATURALLY
reduce pain and boost mood. Flooding the brain
with painkillers, antidepressants, or other drugs
may cause the brain to stop producing endorphins.
Thus, when such a drug is discontinued, a person
may experience a period of discomfort—ranging
from mild to agonizing– until the brain resumes
production of endorphins. What do you think
about antidepressants? Do the benefits
outweigh the potential harm?
Chapter 3
16
The Central Nervous System:
Consists of brain and spinal cord
Chapter 3
17
Central Nervous System (cont’d)
 Spinal cord:
 A column of nerves within the spine that transmit
messages to and from the brain.
 Protected by the spine.
 Spinal reflex: simple, automatic response to
something.
 EX: Remove hand for hot stove!
Chapter 3
18
Other simple Reflexes:
 Blink when dust in your eye
 Sneeze with pepper
 Tapping on knee to see if kick
 Knee-jerk reflex
 Want to try?…sit on desk with legs crossed.
The “doctor” needs to gently strike the knee
with a “karate chop”. Does the knee jerk?
Chapter 3
19
Section 1: The Nervous System
THE PERIPHERAL NERVOUS SYSTEM
 Responsible for transmitting messages between the
central nervous system and all part of the body and
is made up of the somatic and autonomic nervous
system
Chapter 3
20
 The somatic nervous system transmits sensory
messages to the central nervous system.
 Activated by touch, pain, changes in temperature,
and changes in body position.
 Enables us to experience:
 Hot/cold; pain/pressure; helps us
maintain posture/balance.
Chapter 3
21

The autonomic nervous system regulates the
body’s vital functions such as heartbeat and
breathing.
 2 divisions:
1. Sympathetic
2. Parasympathetic
Chapter 3
22
Sympathetic System:
 Activated when a person is going into action,
perhaps because of some stressful event.
 “Fight-or-Flight”
 Prepares you to confront situation or to run away!
 May suppress digestion, increase heart &
respiration rates, and elevate blood pressure.
Chapter 3
23
Parasympathetic Nervous
System:
 Restores body’s reserves of energy after an
action has occurred.
 EX: Heart rate and blood
pressure are normalized,
breathing is slowed, and
digestion returns to normal.
Chapter 3
24
Chapter 3: Section 2
The Brain: Our Control Center
Chapter 3
25
Main Objective:
 Identify the major structures of
the brain, and explain the
functions of each structure.
Chapter 3
26
Brain Divided into 3
Sections:
1. Hindbrain
2. Midbrain
3. Forebrain
Chapter 3
27
Hindbrain:
 Medulla:
 Vital functions such as heart rate, blood pressure, and
breathing.
 Pons:
 Located in front of medulla and is
involved in regulating body movement,
attention, sleep, and alertness.
 Cerebellum:
 Balance and coordination.
Chapter 3
28
The Midbrain:
 Located between hindbrain and forebrain.
 Vision and hearing
 Contains part of reticular activating system:
 Part of brain that is involved in attention, sleep, and
arousal.
 EX: Drugs/alcohol can affect
this alertness.
Chapter 3
29
The Forebrain:
Involved in complex thinking processes!!

4 key areas:
1.
2.
3.
4.
Thalamus
Hypothalamus
Limbic System
Cerebrum
Chapter 3
30
Thalamus:
 The structure of the brain that relays
messages from the sense organs to the
cerebral cortex.
 EX: Relays message to brain, such as pain, in
order for brain to respond.
Chapter 3
31
Hypothalamus:
 The neural structure located below the thalamus
that controls temperature, hunger, thirst, and
various aspects of emotion:

Sexual behavior; caring for offspring, aggression;
etc….
Chapter 3
32
Limbic System:
 A group of neural structures at the base of the
cerebral hemispheres that is associated with
emotion, motivation, hunger, sex, and
aggression.
Chapter 3
33
Cerebrum:
 The large mass of the forebrain, consisting of
two hemispheres.
 Cerebral Cortex:
 The bumpy, convoluted surface
of the brain; the body’s control
and information-processing center.
Chapter 3
34
The Cerebral Cortex: What Makes Us
Unique
 Made up of right and left hemispheres.
 Corpus callosum:
 The nerve fibers that connect
the left and right hemispheres
of the cerebral cortex.
Chapter 3
35
 Information received by one side of the body is
transmitted to the OPPOSITE hemisphere of the
brain.
 Each hemisphere of the
brain is divided into
four parts/lobes.
Chapter 3
36
Complete the following on the SAME
handout!
 Occipital Lobe:
 Vision
Chapter 3
37
Temporal Lobe:
 Hearing/Auditory
Chapter 3
38
Parietal Lobe:
 Sensory Cortex:
 Warmth, cold ,touch ,and pain
Chapter 3
39
Frontal Lobe:
 Motor cortex
 Neurons in the motor cortex fire when we
move certain parts of our body.
Chapter 3
40
Association Areas:
 Association areas:
 Areas of the cerebral cortex that are involved in such
mental operations as thinking, memory, learning,
and problem solving.
 Shape information into something meaningful.
 EX: Puzzle
Chapter 3
41
Language Abilities:
Right-handed people:
Language functions based in left hemisphere
About 2 out of 3 left-handed people:
Language in left hemisphere
Chapter 3
42
2 Key Language Areas:
 Broca’s Area:

Located in frontal lobe.
 Controls area of face used for speaking.
 If damaged, then person speaks slowly,
using simple sentences!
 Wernicke’s Area:

Located in temporal lobe
 Pieces together sounds and sights
 If damaged, then speech becomes meaningless!!
 EX: “Stealing cookies”…pg. 63
Chapter 3
43
Left vs. Right Hemispheres:
 Left Hemisphere:
 Language, logic, problem solving, mathematical
computation.
 Right Hemisphere:
 Imagination, art, feelings, and spatial relations.
Even though have heard “right brained” and “left
brained” the hemispheres DO NOT act
independently of each other!!
Chapter 3
44
Midsaggital Plane:
Chapter 3
45
Turn to Pg. 65
Is Phineas Gage Still the Same
Man???
Chapter 3
46
Methods of Studying the Brain:
Accidents:
1.

2.
Accidents and brain damage
Electrical Stimulation of the Brain:
Stimulate parts of brain to change behavioral
patterns.
Chapter 3
47
3. The Electroencephalogram (EEG):


Electrodes record electrical activity of brain.
Used to diagnose some psychological disorders and
locate tumors.
Chapter 3
48
4. Scans:

CAT scan : Computerized axial tomography


MRI: Magnetic resonance imaging


3-dimensionanl view of brain.
More powerful; shows details more clearly
PET scan: Positron emission tomography

Show activity of brain at given time
Chapter 3
49
Chapter 3: Section 3
The Endocrine System
Chapter 3
50
Main Objective:
 Explain how hormones secreted by the major
glands of the endocrine system affect the
body.
Chapter 3
51
 Endocrine System:
 Consists of glands that secrete substances, called
hormones, into the bloodstream.
 Chemicals produced by the endocrine glands
that regulate specific body functions.
 Glands include:





Pituitary gland
Thyroid gland
Adrenal glands
Testes
Ovaries
Chapter 3
52
Pituitary Gland:
 About the size of a pea.
 “Master gland”…VERY IMPORTANT
 Stimulated by hypothalamus:
 Responsible for the secretion of many different
hormones that affect various aspects of behavior.
 EX: Growth hormones; Prolactin (stimulates milk on
nursing women)
Chapter 3
53
The Thyroid Gland:
 Produces Thyroxin:
 Affects body’s metabolism…its rate of converting
food to energy.
 Hypothyroidism: Too little thyroxin
 Can lead to overweight.
 Cretinism: Too little thyroxin in children.
 Stunted growth/ mental retardation
Chapter 3
54
The Adrenal Glands:
 Located above the kidneys
 Outer layer (cortex):
 Secrete cortical steroids, which increase resistance to
stress & promote muscle development.
 Also, cause liver to release stored sugar,
making energy available for emergencies.
Chapter 3
55
Adrenal Glands (cont’d)
 Also produce adrenaline and noradrenalin:
 Released when sympathetic nervous
system activated.
 Help arouse body, enabling
person to cope with stressful
situation.
Chapter 3
56
Section 3: The Endocrine System
The Testes and the Ovaries:
 Testes and Ovaries – produce the hormones
testosterone, estrogen, and progesterone that
play an important role in development,
development of primary and secondary sex
characteristics and have psychological as well as
biological effects.
Chapter 3
57
Testosterone:
 Male sex hormone.
 Small amount in females produced by ovaries.
 Produced by testes in males.
 Stimulates growth of male
sex organs.
Chapter 3
58
Estrogen and Progesterone:
 Female sex hormones produced by ovaries.
 Low levels found in men.
 Responsible for the following:
 Breast enlargement; regulates menstrual cycle; PMS;
higher levels of estrogen connected with feelings.
Chapter 3
59
Chapter 3: Section 4
Heredity:
Our Genetic Background
Chapter 3
60
Main Objective:
 Explain the role of chromosomes and genes in
heredity and evaluate the methods used by
psychologists to study the role of heredity in
determining traits.
Chapter 3
61
What is Heredity??
 Heredity:
 The transmission of characteristics from parents to
offspring.
 Contribute to the following:
 Appearance, personality,
psychological disorders
Chapter 3
62
Genes and Chromosomes:
 Genes:
 The basic building blocks of heredity.
 Traits determined by pairs of genes…one gene in each
pair from each parent.
 Chromosomes:
 Threadlike structures in which genes are found, which are
composed of DNA (deoxyribonucleic acid)
 Double helix
 46 chromosomes with 23 pairs
 In pairs…one from mom and
one from dad.
Chapter 3
63
Oh!!! It’s A ?????
 23rd pair:
 Determines sex
 Female:
 2 X-chromosomes
 Male:
 1 X & 1 Y chromosome
 Father determines sex of baby!
Chapter 3
64
Nature vs. Nurture:
 Nature:
 What people inherit.
 Nurture:
 Environmental factors
 Family, education, culture,
everyday living experiences
Chapter 3
65
What do most psychologists
believe??
Believe nature & nurture are equally important!
Chapter 3
66
Kinship Studies:

Kinship:

Refers to the degree to which people are related,
based on genes.

2 Common types:
1. Twin Studies
2. Adoptee Studies
Chapter 3
67
Twin Studies:
 Identical twins:
 Differences due to environment (nurture)
 More likely to share personality traits & psychological
disorders (Ex: autism)
 Fraternal twins:
 Differences due to genes
AND environment
 Share 50% of genes
Chapter 3
68
Adoptee Studies:
 If children act more like biological families –
then behavior may be largely influenced by
heredity!!
 Provides ways of sorting
out the effects of nature
and nurture
Chapter 3
69
Twins Reared Apart:
 Psychological and personality traits are influenced
by heredity.
 A way of finding out that
twins reared apart share many
of the same mannerisms despite
their separation
 EX: Intelligence, aggression, leadership.
 http://www.youtube.com/watch?v=Vlr4mwtjEKY
Chapter 3
70
Does Heredity Determine Our
Personalities??
Turn to Pg. 73
Chapter 3
71
End of Chapter 3