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Biology & Behavior
Chapter 2
Section 1: The Nervous System
• It’s almost like running is this great friend we
both share…Anyway, that’s what I’d like to talk to
you about… running as a friend, as a companion,
a lover even…in other words, the relationship of
running. “WHAT!?” many of you will be saying. “I
thought that I was going to learn how to improve
my 10k time.” GO read Runner’s World for that.
You see, I don’t view running as what I DO or who
I AM, but as this thing, this force, that changes
me over time.
– From “Running and Me: A love Story” by Joan Nesbit,
1999
Neurons
• Nerve cells that run through our entire body
and communicate with one another
• 100 billion neurons, most found in brain
The Nervous System
Central Nervous System
• Brain & Spinal Cord
Peripheral Nervous System
• Nerve cells that send
messages between the
central nervous system and
all parts of the body
Parts 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
• Axons –carries
messages away from
cell body
• Myelin – white fatty
substance that insulates
and protects the axon;
also speeds up
transmission of
messages
• Axon terminals – small
fibers at the end of the
axon
The Communication Process
• Messages sent from the
axon terminals of one
neuron to dendrites of
other neurons
• Crosses synapse (junction
between the axon
terminals of one neuron
and the dendrites of
another neuron)
• Messages travel in only one
direction
Neurotransmitters: Chemical Messengers
• Neurotransmitters (the
message)are chemicals that are
stored in axon terminals
• Neurons can fire hundreds of
times every second
• Several types of
neurotransmitters, each with
their own structure
The Central Nervous System
• Transmits messages
between the brain
and the muscles and
glands throughout
the body
• Also involved in
spinal reflexes
The Peripheral Nervous System
• Made up of the Somatic
Nervous System & the
Autonomic Nervous System
The Somatic Nervous System
• AKA the skeletal nervous system
• Transmits sensory messages to the CNS
• Activated by touch, pain, changes in temperature,
changes in body position
• Enables us to experience hot and cold and to feel pain
and pressure
• Helps us maintain posture and balance
The Autonomic Nervous System
• Regulates body’s vital
functions (heartbeat,
breathing, digestion, blood
pressure)
• Don’t have to think about
these activities...happen
automatically
• Made up of the Sympathetic
& Parasympathetic nervous
systems
Sympathetic Nervous System
• Prepares body for action
• To either run away or
confront situation
• “Fight or Flight” response
• Suppresses digestion,
increases heart &
respiration rates, elevates
blood pressure
Parasympathetic Nervous System
• Restores the body’s reserves of energy after
an action has occurred
• Heart rate & blood pressure are normalized,
breathing slowed, digestion returns to normal
Nervous
System
CNS
Spinal
Cord
Brain
PNS
Autonomic System
(involuntary muscles &
internal organs)
Somatic System
(voluntary muscles &
sense organs)
Parasympathetic System
(Calms body after
emergencies
Sympathetic System
Prepares body for
action
For homework:
• On a half sheet of paper… explain how a
neuron works using the metaphor of a relay
race. Be sure to be specific and detailed in
your description.
Section 2: The Brain
The Brain
• Mind, or
consciousness, dwells
within the brain
• Divided into 3
sections
1. Hindbrain
2. Midbrain
3. Forebrain
http://www.youtube.com/watch?v=VF5PyeMG8Lo&safety_mode=true&persist_safety_mode
=1&safe=active
Hindbrain
• Medulla oblangata –
Involved in vital functions
(heart rate, blood
pressure, and breathing)
• Pons –regulates body
movement, attention,
sleep, and alertness
• Cerebellum – “little
brain” – balance and
coordination
Midbrain
• Vision & hearing
• Contains part of
reticular
activating system
– Important for
attention, sleep,
and arousal
– Increases heart
rate & blood
pressure
Forebrain
• Four major areas
1.
2.
3.
4.
Thalamus
Hypothalamus
Limbic System
Cerebrum
Thalamus
• A relay station for sensory stimulation
Hypothalamus
• Regulates body temperature,
storage of nutrients, &
various aspects of motivation
& emotion
• Involved in hunger, thirst,
sexual behavior, caring for
offspring, & aggression
• Disturbances within the
hypothalamus can lead to
unusual drinking & eating
behaviors
Limbic System
• Involved in learning
and memory, emotion,
hunger, sex, and
aggression
• If damaged, people
can recall old
memories but not
create new ones
Cerebrum
• Surface of cerebrum
known as the cerebral
cortex (outer layer of
brain)
• Part that makes us
uniquely human – the
part that thinks
• Also deals with memory,
language, emotions,
complex motor
functions, perception
Cerebral Cortex
• Divided into two hemispheres
• Corpus Callosum connects two hemispheres
• Information received by one side of the body
is transmitted to the opposite hemisphere
• Each hemisphere is divided into four lobes
1.
2.
3.
4.
Frontal Lobe
Parietal Lobe
Temporal Lobe
Occipital Lobe
Senses and Motor Behavior
• Occipital lobe contains primary visual area
– Damage creates unusual conditions: may be able
to recognize an object but unable to differentiate
it from another similar object
• Temporal lobe contains hearing or auditory
area
– If damaged a person may not be able to recognize
common sounds
• Parietal lobe – receives messages from skin
senses (warmth, touch, cold, pain)
• Frontal lobe – home to the motor cortex
(neurons fire when we move certain parts of
our body)
Association Areas
• Shape information into something meaningful
• Frontal lobe association areas where we solve
problems, make plans and decisions
Left vs. Right Hemispheres
Left Hemisphere
• Language functions, logic,
problem-solving, math
Right Hemisphere
• imagination, art, feelings,
spatial relations
• For nearly all right-handed people, language functions are based
in left hemisphere
• Language functions also based in left hemisphere for 2/3rds of
left-handed people
• Although differences exist between two hemispheres, they don’t
act independently of each other
How do we study the brain?
• Accidents
• Electrical Stimulation of the Brain – shows that specific
areas are associated with specific types of sensations
• EEG – device that records electrical activity in the brain
• Scans
– MRI – lie in a magnetic field – brain gives off extra energy
from radio waves and creates visual images
• Good for small injuries
– CAT – X-ray beams passed through head and form 3-d
images of brain
– fMRI – fast kind of MRI that shows the brain at work
– PET – radioactive sugar injected into body – as it reaches
the brain – more is used in areas of greater activity –
images show this activity
Section 3: The Endocrine System
The Endocrine System
• Glands that secrete hormones into the bloodstream
• Pituitary Gland – The “master gland”
– Secretes growth hormone, hormone to stimulate labor in
pregnant women
• Thyroid Gland – controls metabolism
• Pineal Gland – produces melatonin & affects sexual
development
• Adrenal Gland – produce adrenaline & nonadrenaline
• Testes & Ovaries – produce testosterone, estrogen,
progesterone
Section 4: Heredity
Heredity
• Transmission of characteristics from parents to
offspring
• Genes – basic building blocks of heredity
• 46 chromosomes divided into 23 pairs
• 23rd chromosome – boys xy and girls xx
– Dad determines sex of offspring
Nature-Nurture Debate
• Nature
– What people inherit
– Inherited characteristics
determine the kind of
people we are
• Nurture
– Environmental factors
• Family, education,
culture, living conditions,
everyday experiences
• Today, most psychologists believe both are involved
Kinship Studies
• Common way to study nature vs. nurture
• Twin studies – to determine which traits are
genetically inherited
• Adoption studies – do kids act more like
biological or adopted parents?
• Twins reared apart – still share many traits