Chapter 3
What is another name for Neuron?
nerve cells
Nerve impulse in the form of electrochemical impulse runs
through our entire body and communicate with each other
(glands, muscles)
Regulates our internal functions
Learn new behavior or information - N.S.
Registers experience and changes to accommodate its storage
Why do you think the transparency show the anatomy of
two neurons instead of one?
Because the function of the neurons is to communicate
with one another.
TRANSMITS IN ONE DIRECTION
Chapter 3
EACH NEURON HAS: (pg. 54)
CELL BODY – produces energy that fuels cell activity
AXON – Carries messages away from the cell body
Axon has MYELIN - white fatty substance insulates and protects
axon
MYELIN SHEATH - protects the axon and helps speed up
the transmission of the message
DENDRITES - receives information from other neurons and pass
information through the cell body
Leafy fibers branching out – contain neurotransmitters
AXON TERMINALS pass messages from one neuron to the
dendrites of the next neuron.
Neurotransmitters are chemicals stored in sacs in the axon
terminals. When released chemicals cross the synapse to reach the
next neuron.
SYNAPTIC GAP - space between axon terminal and membrane
of the postsynaptic cell (dendrite)
SYNAPSE - the space between 2 cells
that separates the axon terminals of sending neuron from the dendrites of its
receiving neuron.
New synapse can develop between neurons not previously connected when
learn something new
Chapter 3
NEURON IMPULSE TRAVELS ONLY IN ONE DIRECTION
and takes a fraction of a second.
Pain is transmitted through SENSORY NEURONS which carry
information received by senses to CNS
MOTOR NEURONS - carry information from CNS to muscles /
glands
INTER NEURONS - specialized nerve cells within the brain and
spinal cord that communicate internally and intervene between
sensory inputs and motor inputs
Chapter 3
NEUROTRANSMITTERS
Neuron releases only ONE type of neuron transmitter.
Each type of neurotransmitter has a specific structure and fits into a receptor
site on the next neuron like a key fits a lock.
1. ACETYLCHOLINE
involves in the control of MUSCLES as well as AROUSAL, MEMORY,
MOTIVATION (motor neurons - spinal cord stimulates muscles)
Patients who have low levels of acetylcholine may help Alzheimer disease if use a chemical
stimulate enhances memory
Patients who have high levels lead to spasms and tremors
2. DOPAMINE
involved in MOTOR BEHAVIOR, LEARNING, REINFORCEMENT,
maintain FOCUS and ATTENTION
deficiency - plays role in Parkinson’s (tremor, uncoordination)
excess - contribute to PD - schizophrenia
Chapter 3
NEUROTRANSMITTERS
3. NORADRENALINE
involved in preparing the BODY FOR ACTION, CONTROL,
ALERTNESS
4.**EPINEPHRINE (ADRENALINE)
prepare body fight/flight
**Hormone and/or neurotransmitter
5. NOREPINEPHRINE
brings body back to slow level, calm tranquilizes body after
stress
6. ENDORPHINS
morphine; dulls pain; addictive pain suppressors brain response to
pain
7. SUBSTANCE P - pain
8. SEROTONIN
involved in EMOTIONAL AROUSAL & SLEEP, EATING
DISORDERS, MOOD
low levels - Depression, OCD
(Prozac raise serotonin level to brain)
Chapter 3
CENTRAL NERVOUS SYSTEM
Made up of spinal cord and brain
FUNCTIONS OF THE SPINAL CORD
Spinal cord transmits messages between the brain and the muscle and
glands of the body and is involved in reflex action.
WHAT IS THE SPINAL REFLEX ACTION? - simple automatic response
to something.
ex. touching a hot stove; removal of hand is a spinal reflex by motor
neuron
pain does not cause the reflex - a person may register pain in head but pain not
felt until after the hand has been removed.
Ex. Blinking your eyes when lights are turned on in dark room because
pupil automatically contracts when exposed to bright light;
Ex. knee jerk - lower leg swings.
Spinal reflex action DOES NOT receive its triggering message from the
brain.
Message goes from the sensory nerve to the spinal cord where special
cells send a message to appropriate motor neurons which stimulate the
muscles to take action.
Chapter 3
PERIPHERAL NERVOUS SYSTEM
Lies outside the central nervous system and is responsible for transmitting messages
between central nervous system and all parts of the body.
3 MAIN DIVISION OF peripheral nervous system:
1.SOMATIC Nervous System
•
Transmits sensory messages to the central nervous system
•
Activated by touch, pain , changes in temperature, changes in body position
•
Enables us to experience sensations of hot/cold and feel pain/pressure
•
Also sends message to muscles and glands and helps maintain posture and
balance.
2. AUTONOMIC Nervous System
•
occurring involuntarily or automatic
•
regulates the body’s vital functions: Heartbeat, Breathing, Digestion, and Blood
Pressure, tear production
Psychologists are interested in this Nervous System because OBSERVING RESPONSE when
a person experiences something STRESSFUL in the environment.
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PERIPHERAL NERVOUS SYSTEM
2 DIVISIONS of AUTONOMIC NERVOUS SYSTEM:
1. SYMPATHETIC Nervous System
 Activated when a person is going into an action, perhaps because of
some stressful event.
 Prepares body either to confront the situation OR run away =
FIGHT or FLIGHT response
Ex. Attack by a dog
 Prepares body by suppressing digestion, increasing heart &
respiration rates, elevates blood pressure
Ex. POP QUIZ
 Sympathetic Nervous System is overly active in people who are
anxious, including people with anxiety disorders. Over activity in
SNS leads to high blood pressure, stroke, or heart problems
Chapter 3
PERIPHERAL NERVOUS SYSTEM
AUTONOMIC NERVOUS SYSTEM
2. PARASYMPATHETIC Nervous System
 Restores the body’s reserves of energy after an action has occurred.
 Heart rate and blood pressure are normalized
 Breathing slowed, digestion returns to normal
REMEMBER: Sympathetic starts with S = STRESS
Parasympathetic starts with P = PEACE
PERIPHERAL NERVOUS SYSTEM
3RD DIVISION
3. ENTERIC Nervous System
 Meshwork of nerve fibers that innervate the viscera (gastrointestinal
tract, pancreas, and gallbladder)
Chapter 3
Brain functions effectively because intricate system of support and
protection receives from other parts of body.
Brain supported by nutrients and oxygen carried by blood
vessels
PROTECTED:
By bones of the skull
3 layers of membranes (meninges) (meningeez)
Fluids surrounds brain acts as a SHOCK ABSORBER
LOCALIZATION OF FUNCTION - different parts of brain carry
out different functions
LATERALIZATION - some functions are carried out exclusively on
one side of the brain, even for functions that take place on both sides of
brain. Right/Left sides usually take care of different aspects of same
functions.
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VITAL FUNCTIONS
HINDBRAIN
heart rate
blood pressure
respiration
balance/coordination
MIDBRAIN
Vision and hearing
FOREBRAIN
Complex function: thought & emotion
Chapter 3
MAIN STRUCTURE
HINDBRAIN - Basic body activities. Connects spinal cord with rest
of body.
Medulla directly connects the spinal cord with brain and helps
regulate HEART RATE, BLOOD PRESSURE and
BREATHING
Cerebellum next to the medulla behind the brain stem (“little
brain”); controlling balance & coordination, posture
and maintaining equilibrium; allows us to walk and run
without tripping
Pons just above the medulla; Regulates BODY MOVEMENT
(facial expression), ATTENTION, SLEEP, ALERTNESS,
EATING
(Produces chemicals help maintain sleep wake cycle)
Chapter 3
Reticular Activating System (RAS) network of neurons extending from the medulla to forebrain
(acts as a filter)
Allows sensory information to enter brain
i.e. sleep & arousal
ex. AIR TRAFFIC CONTROL OF BRAIN
regulates the flow of traffic
ex.
Teacher calls your name your RAS stimulates the higher brain
centers that allows you to become alert.
When asleep RAS restricts most environmental stimuli from entering
your brain.
Chapter 3
MIDBRAIN - important for hearing and sight; one place in brain
where pain is registered
Connects HINDBRAIN and FOREBRAIN
Midbrain appears to function mainly as a relay station for
messages coming into the brain.
It also contains structures that play a role in seeing, hearing,
and movement.
Reticular Activating System - network of neurons extending from
the medulla to forebrain; allows relevant sensory information such as
AROUSAL or SLEEP to enter the brain. (air traffic control of the brain
- regulates the flow of traffic); controls overall level of activity of central
nervous system including WAKEFULNESS and SLEEP
Ex. teacher calls your name - RAS stimulates higher brain centers that allow you to
become alert. OR while sleeping your reticular formation restricts most environmental
stimuli from entering your brain.
Chapter 3
FOREBRAIN
Biggest and most complex part
It not only influences many of the basic life-support functions controlled
by the midbrain and hindbrain but is also responsible for such higher
level behaviors as thinking and speaking.
Major structures of the forebrain:
Thalamus
• major sensory relay center to cerebral cortex
• influences mood and movement.
• Includes visual, auditory, touch stimuli.
• Messages from these sense organs are channeled into the thalamus
and from there are carried into specific parts of the forebrain for
interpretation and action.
Chapter 3
Hypothalamus
 (Size of pea) maintains stable internal environmental state
 involved in the motivation of such behaviors as: eating
drinking, sexual drive, sleeping, and regulating body
temperature, storage of nutrients.
 It also influences the pituitary gland which regulates biochemical
reactions in the body and the part of the peripheral nervous system
that regulates the internal body organs. pg.60
Chapter 3
Limbic System - autonomic response to SMELL, EMOTION,
MOOD & other functions like sex, aggression, fear , pressure,
pain.
4 important parts:
hypothalamus, thalamus, hippocampus, amygdala
 The hypothalamus regulates motivation and emotion.
 The thalamus primarily relays sensory information to the
cerebrum, the part of the brain that allows humans to think and
store information.
 The hippocampus is involved in memory processing and learning.
(Alzheimer’s disease patients often have low levels of acetylcholine in the
hippocampus.) People with severe damage to this area can still
remember, names, faces, events, before incident; can’t remember
anything new.
 The amygdala is involved in anger and aggression.
Automatic response to smell, emotion, mood, and other such functions:
sex, aggression, fear, pressure and pain.
Chapter 3



Basal Ganglia (base of forebrain)
lie to the side of the thalamus and are important in voluntary motor
responses (movement).
The neuromuscular disorder Parkinson’s disease is associated with a
breakdown of the neurotransmitter dopamine in the basal ganglia.
If part of the limbic system is damaged people can recall old memories
but don’t create new memories. May make you more
passive/aggressive.
Chapter 3
Cerebrum is the largest part of the forebrain; consists of two
distinct structures called HEMISPHERES;
Hemispheres are connected by the corpus callosum= bundle of
neurons that keeps each hemisphere informed about what is happening in
the other.
Left Hemisphere controls the right side of the body and
Right hemisphere controls the left side.
Left Hemisphere - logical, analytical and verbal - reading,
language, and understanding speech
Right Hemisphere process nonverbal info and concerned
with emotion, imagination, and artistic information.
Most people are left dominant
Chapter 3
Paul Broca - BROCA’s AREA
located in Frontal lobe
essential ability to talk (produces speech sounds)
important for talking
If Broca’s area damaged:
APHASIA = (speechlessness) tends to expressive; language difficulty lies
predominantly in sequencing and producing language (talking)
Results from patients who suffered left hemisphere strokes and result
brain damage. Produce language problems = APHASIA
Chapter 3
Karl Wernicke later modified - Wernicke’s AREA
toward back of temporal lobe
processing and understanding what others saying
important to listening
If Wernicke’s area damaged:
APHASIA = tends to be RECEPTIVE; difficulty understanding
language
Chapter 3
WHAT IS THE RELATIONSHIP BETWEEN THE CEREBRAL
CORTEX AND THE CEREBRUM?
Cerebral Cortex - is outer layer of the cerebrum (wrinkle
ridges) ; controls overall level of activity of CNS


Part of the brain used for THINKING - where messages from our
SENSE ORGANS are interpreted and stored and where decisions
about behavior are made.
Has distinct sections/lobes that control different activities.
(thought, voluntary movement, language, reasoning, perception)
BRAIN STEM –
area between thalamus and spinal cord
structure within brain stem includes medulla, pons, RAS
Functions: breathing, heart rate, blood pressure
Chapter 3
LOBES – Frontal, Occipital,Temporal, Parietal
Vision - Occipital - allow you to interpret what you see in the
environment
Hearing - Temporal - when you hear your teacher talking
Somatosensory- Parietal - temperature, touch, pain
Movement/memory - Frontal - when you remember past events or
giving an answer to a question
Left frontal more active than right frontal - tend to be more cheerful,
sociable, self-confident
Right frontal more active than left frontal - more stressed, frightened,
upset by unpleasant things more suspicious and depressed
Chapter 3
METHODS OF STUDYING THE BRAIN
EEG - Electroencephalography - records general wave patterns of
electrical activity
CAT - Computerized Axial Tomography - x-rays reveal brain
abnormalities; creates cross sectional pictures of brain only shows
density of tissue of how much radiation absorbed [contrast]
PET - Positron Emission Tomography - injects with radioactive glucose;
examines brain activity
MRI - Magnetic Resonance Imaging -use radio waves and magnetic fields
to study chemical activity of brain cells.
Chapter 3
ENDOCRINE SYSTEM
Consists of glands that secrete substances called HORMONES
into the BLOODSTREAM
Hormones stimulate growth and many kinds of reactions - activity
levels and moods
Hormones affect behavior & emotional reactions
Hormones have specific receptor sites.
Hormones produced by several different glands.
Glands include:
PITUITARY GLAND = MASTER GLAND (lies under the hypothalamus)
Stimulated by Hypothalamus - responsible for secretion of various hormones affect
various behaviors
a. Growth hormone - regulates growth of muscle, bone, glands
b. Females to pregnancy and Production of milk
THYROID
ADRENAL
TESTES & OVARIES
Chapter 3
THYROID GLAND
Produces THYROXIN
affects body’s metabolism and converts food to energy
ADRENAL GLAND
Located above kidneys
Outerlayer or cortex - secrete CORTICAL STEROIDS - increase
resistance to stress and promote muscle development.
Also produces ADRENALINE & NORADRENALINE
These hormones arouse body enabling person to cope with stress
Adrenaline - can intensify emotions such as fear & anxiety, raise blood
pressure
This hormone acts as a neurotransmitter as well
Chapter 3
HEREDITY
Transmission of characteristics from Parents to offspring
plays key role in development of traits
shown to be one factor involved in psych disorders (PD): anxiety,
depression, schizophrenia, bipolar disorder, alcoholism
KINSHIP STUDIES
Common way to sort out roles that heredity and environment play
determining a trait
Kinship refers to degree how people related.
Identical twins share 100% of genes
Psych use info to determine how much a trait is influenced by genetics
and how much by environment
2 Types of KINSHIP STUDIES
1.
Twin
2.
Adoptees