Download Bio Bases 2014 - Doral Academy Preparatory

AP PSYCH REVIEW
THE BIOLOGICAL BASES OF BEHAVIOR
2013-2014
(8 – 10 %)
 Overview
o The basis for the biological approach is the neuroscience or
biopsychological perspective
 The activity of the brain and its neurotransmitters helps to explain
our behavior
 Neuroanatomy
o the study of the parts and function of neurons
o neurons  individual nerve cells that make up our entire nervous system
 Parts of the Neuron
o Dendrites  rootlike parts of the neuron that arise from the cell body;
grow to make synaptic connections with other neurons
o Cell body (soma)  contains the nucleus and other parts of the cell to
sustain life
o Axon  Wirelike structure ending in the terminal buttons that extends
from the cell body
o Myelin sheath a fatty covering around the axon that speeds neural
impulses
o Terminal buttons (end buttons, terminal branches, synaptic knobs) the
end of the axon that contains neurotransmitters
o Neurotransmitters chemicals contained inside the terminal buttons
that enable neurons to communicate; neurotransmitters fit in receptors
sites on the dendrites much like a key fits into a lock
o Synapse the space between the terminal buttons of one neuron and the
dendrites of the next
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 Neural Firing
o In its resting state, the neuron has a slightly negative charge
o Terminal buttons from neuron A are stimulated and release
neurotransmitters into the synapse, which fit into receptors sites in
neuron B
o If enough neurotransmitters are received then the threshold is met
 The cell membrane of neuron B becomes permeable, letting
positive ions rush inside the cell
 The inside now becomes positive; this change in polarity spreads
down the length of the axon in neuron B, like a bullet from a gun 
the action potential (the electric message firing)
 Travels 120 meters per second
o When the charge reaches the terminal buttons of neuron B the buttons
release neurotransmitters into the synapse
o The all or nothing principle states that a neuron will fire COMPLETELY
 The threshold for firing must be met
 Neurotransmitters
o Excitatory  they excite the next cell into firing
o Inhibitory  they inhibit the next cell from firing
o The type of neurotransmitter received will determine whether the
neuron fires or doesn’t
Major Types of Neurotransmitters
Neurotransmitter
Function
Problems Associated with
Excess or Deficit
Acetylcholine (AcH)
Motor Movement
Lack of AcH = Alzheimer’s
Dopamine
Motor movement &
Lack = Parkinson’s ; too
alertness
much = Schizophrenia
Endorphins
Pain control
Involved in addiction
Serotonin
Mood control
Lack = clinical depression
GABA
Important inhibitory
Seizures and sleep
neurotransmitter
problems
Glutamate
Excitatory
Migraines and seizures
neurotransmitter and is
involved in memory
Norepinephrine
Alertness/Arousal
depression
 The Nervous System
o Afferent neurons  take information from the senses to the brain
o Interneurons once information reaches the brain or spinal cord,
interneurons take the messages and send them to other parts of the brain
or to efferent neurons
o Efferent neurons (motor neurons)  take information from the brain to
the rest of the body
 The “e” in efferent is easily remembered as exiting the brain
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The Organization of the Nervous System
 The Nervous System
o Central Nervous System (CNS)  contains the brain and spinal cord
 Spinal cord bundle of nerves that runs through the center of the
spine
o Peripheral Nervous System (PNS) all the other nerves in our body NOT
encased by bone
 Divided into the somatic and autonomic
 Somatic controls our VOLUNTARY muscle movements
o The motor cortex in the brains sends impulses to the
SNS allowing us to move
 Autonomic controls the automatic functions of our body
and deals with stress reactions
o Divided into sympathetic and parasympathetic
 Sympathetic  mobilizes our body to
respond to stress; accelerates heart rate,
blood pressure, and respiration, but
conserves energy for quick response
 Parasympathetic  slows down our body
after a stress response
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
Slows down autonomic system
responses
 Peripheral Nervous System Transmission
 You awake in the middle of the night to go to the restroom
 On the way back you stub toe against the corner of your
bed
 Sensory neurons in your toe are activated and afferent
neurons are sending this message up your spinal cord
 The message reaches your brain and efferent neurons in
your motor cortex cause you to hop up and down
 Reflexes
 You are rummaging through your drawer when a
thumbtack pricks you in the finger
 You immediately jerk your hand back and see the damage
you’ve inflicted on yourself
 This message DID NOT reach the brain
 Reflexes stop at the spinal cord
 Are adaptive as they ensure our survival
 Studying the Brain
o Accidents
 1848  The Case of Phineas Gage
 Gage had a railroad spike thrust through his brain
 His doctors took notes documenting the brain damage and
how Gage’s behavior changed
 Gage became highly emotional and impulsive after the
accident
 They concluded the front part of the brain deals with
emotions and decision-making
o Lesioning
 The deliberate destruction or removal of one part of the brain
 Done solely for experimental purposes
 In other cases, it is inevitable
 A patient has a brain tumor that cannot be removed with
removing parts of the surrounding brain
 Doctors will monitor the patients subsequent behaviors for
any changes
 Frontal lobotomy a historical example of lesioning
 The purposely destruction of front part of the frontal lobe
 Formerly done as a method of last resort
 Now replaced by drug treatments
o Electroencephalogram (EEG)
 To detect brain waves
 Researchers can use this to determine which waves are present as
we cycle through the different stages of consciousness
 Useful in sleep studies
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o Computerized Axial Tomogrpahy (CAT or CT)
 A sophisticated x-ray
 CT scans use several x-ray cameras rotating around the brain to
produce a detailed 3-D image of the structure of the brain
 Used to find any brain abnormalities
o Magnetic Resonance Imaging (MRI)
 Similar to the CT scans, but the MRI uses magnetic fields and
provides a more detailed image
 Measures the density and location of brain material
o Positron Emission Tomography (PET)
 Allows researchers to see what areas of the brain are most active
during certain tasks
 Measures how much glucose parts of the brain are using
o Functional MRI (fMRI)
 Combines the elements of PET scans and MRIs
 Shows detail of brain structure along with direction of blood flow
in the brain
 Shows brain function
 Ex: how we know autistics process faces and objects in the
same part of the brain
 Brain Structure and Function
o Hindbrain located at the top of the spinal cord and contains the:
 Medulla blood pressure, heart rate, breathing
 AKA the medulla oblongata
 Pons located above the medulla and connects the hindbrain with
the midbrain and the forebrain
 Involved in facial expression
 Remember, the pons yawns
 Cerebellum located on the bottom rear of the brain
 Literally means little brain
 Coordinates some habitual muscle movements, such as
tracking objects in space and playing a musical instrument
o Midbrain
 Coordinates simple movements with sensory information
 Located above the hindbrain, but below the forebrain
 Ex: allows you to read this page as you turn your head to
follow the text
 In this case, it is integrating your sensory experiences
(seeing) with muscle movements (tilting your head)
o Forebrain
 Where the magic of thought and reason occur
 It is what makes humans, human
 Composed of the:
 Thalamus
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o sits on top of the brain stem and is responsible for
receiving the sensory signals from the spinal cord
and sending them to the appropriate areas of the
forebrain
Hypothalamus
o right next to the thalamus and controls metabolic
functions such as body temperature, sexual arousal,
hunger, thirst, and the endocrine system
o Also might be involved in controlling our circadian
rhythms
Amygdala
o Vital to our experiences of emotion
o Add emotion to memory and its proximity to the
hippocampus validates this claim
 Remember, don’t make Amy angry
Hippocampus
o Vital to our system of memory
o Memories are processed through this area and then
sent to other areas of the cortex
o Damage to this area leads to difficulty in retaining
new information
 Remember if you saw a HIPPO on CAMPUS
you wouldn’t forget
 Cerebral Cortex
o The gray wrinkled area that covers the surface of the brain
o Contains densely packed neurons
o The wrinkles are know as fissures, which increase the surface area of the
brain
 More wrinkles = more surface area
 Hemispheres
o The cerebral cortex is divided into left and right hemispheres
 Left hemisphere gets sensory input from and controls the right
side of the body
 Right hemisphere gets sensory input and controls the left side of
the body
 This is known as contralateral control
o The left hemisphere seems to be more active in
 Language, logic, and sequential tasks
o The right hemisphere seems to be more active in
 Spatial and creative tasks
o The left/right brain theory is known as brain lateralization or
hemispheric specialization
o These differences can be accounted for in split-brain patients
 The corpus callosum (connects left and right hemispheres) is
severed to reduce the severity of seizures
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This procedure was pioneered by Roger Sperry and Michael
Gazzinga
 They reported split-brain patients
 Cannot orally report information only presented to the
right hemisphere (left side of body)
Areas of the Cerebral Cortex
o Any area of the cerebral cortex NOT associated with receiving sensory
information or controlling muscle movements is an ASSOCIATION AREA
Frontal Lobes
o Large areas of the cerebral cortex located at the top front part of the brain
behind the eyes
o The anterior or front of the frontal lobe is the prefrontal cortex
 Plays a critical role in directing our thought processes
 Is the brain’s central executive and is believed to be important in
foreseeing consequences, pursuing goals, and maintaining
emotional control
o Frontal lobe in the left hemisphere
 contains Broca’s area  responsible for controlling the muscles
involved in speech
 damage leave the person unable to make the muscle
movements necessary to generate speech
o The Motor Cortex
 a thin vertical strip at the back of the frontal lobe
 sends signals to our muscles, controlling voluntary muscle
movements
 the top of the body is controlled by neurons at the bottom of this
cortex and vice-versa
Parietal Lobes
o Located behind the frontal lobes
o Contain the somatosensory cortex (sensory cortex)
 Receives incoming touch sensations from the rest of the body
 The top of the sensory cortex receives information from the
bottom of our body and vice-versa
Occipital Lobes
o The very back of the brain, farthest from our eyes
o Purpose is to process messages from our eyes
o Impulses from the retinas in our eyes are sent to the visual cortex to be
interpreted
Temporal Lobes
o Process sounds sensed by our ears
o Sounds waves are processed by the ears  turned into neural impulses
 interpreted by our auditory cortices
o Auditory cortices are not lateralized  left ear to left temporal lobe, and
vice-versa
o Wernicke’s area is in the left temporal lobe
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Interprets both written and spoken speech
Damage = the inability to understand language
Speech would sound fluid, but lack appropriate syntax and
grammatical structure needed for meaningful communication
 Brain Plasticity
o The adaptation of certain parts of the brain to take over for damaged
parts of the brain
o Younger brains are more plastic than older ones, thus more likely to
compensate for damage
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 The Endocrine System
o A system of glands that secretes hormones that affect different biological
processes in our body
o Regulated by the hypothalamus, which in turn regulates the pituitary
gland (master gland)
 Adrenal Glands
o Produce adrenaline which signals the rest of the body to prepare for fight
or flight
 Ovaries and Testes
o Produce our sex hormones
o Ovaries = estrogen
o Testes = testosterone
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 Genetics
o Every human cell contains 46 chromosomes arranged in 23 pairs
o DNA makes up chromosomes
o Genes = specific segments on the strand of DNA
o Recessive genes only express themselves if two are inherited
o Dominant genes are expressed if there is a combination
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 Twins
o MZ twins share 100% of their DNA in common
o Thomas Bouchard
 Found more than 100 identical twins given up for adoption and
raised in different families
 Findings
 IQ  .69 correlation for identical twins raised apart and .88
correlation for identical twins raised together
 Confound effective psychological environment
o MZ twins raised together seem to be treated the
same as they are identical
 Chromosomal Abnormalities
o Men are XY
o Females are XX
o Turner’s syndrome
 Born with a single X in the 23rd pair
 Shortness, webbed necks, and differences in physical sexual
development
o Klinefelter’s syndrome
 Have an extra X, resulting in XXY
 Leads to minimal sexual development and personality traits such
as introversion
o Down’s Syndrome
 Born with an extra X in the 21st pair
 Rounded face, shorter fingers and toes, slanted eyes, some degree
of mental retardation
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