UNIT 3: BIOLOGICAL BASES OF BEHAVIOR
Brain facts:
--The average brain is about the size of a grapefruit
--About 3 lbs in weight
--100 billion nerve cells – each cells connects to up to 10,000 other nerve cells
--At age 70, a person retains about 98% of their nerve cells
--The brain has three main parts: the cerebrum, the cerebellum, and the brain stem (medulla).
--Although the brain is only 2% of the body's weight, it uses 20% of the oxygen supply and gets 20% of the
blood flow. If brain cells do not get oxygen for 3 to 5 minutes, they begin to die
--Males tend to have a larger brain (based upon relative physical size….women tend to use more of theirs at any given time)
Biological Psychology:
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Key Question:
Core Concept: Everything psychological is simultaneously biological.
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3A: THE NERVOUS SYSTEM AND THE ENDOCRINE SYSTEM pg 51-63
These two systems are the biological bedrock for all our thoughts, emotions, and behaviors.
Neuron: pg 53
Bundles of many neurons are called nerves
Three Major Classes of Neurons
1. Sensory Neuron: pg 62
Also called an afferent neuron
Example: test the water in a shower, afferent neuron carry message to the brain
2. Motor Neuron: pg 62
Also called an efferent neuron
Example: messages from the brain tell your hands just how much to move the shower tap
3. Interneuron: pg 62
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How Neurons Work
Dendrite: pg 53
Types of Messages:
a. excitatory- fire b. inhibitory – don’t fire
Axon: pg 53
Myelin sheath: pg 53
In a nerve cell, the extended fiber that conducts information from the soma to the terminal buttons. Information travels along
the axon in the form of an electrical charge called the action potential
Resting Potential: pg 53
Action Potential:
The nerve impulse caused by a change in the electrical charge across the cell membrane of the axon. When the neuron ‘fires’,
this charge travels down the axon and causes neurotransmitters to be released by the terminal buttons.
All-or-None Principal: pg 54
Synapse: pg 55
To pass the message across the synaptic gap (aka synaptic cleft), a neuron must initiate a process in the terminal found at
the end of the axon. Synapse also occur between the neurons and the muscles or glands they serve.
Terminal: pg 56
Neurotransmitters: pg 55-58
If they are the right shape, they fit into receptors, simulating the receiving neuron and the message is carried forward.
After the transmitting molecules have done their work, they are broken down by chemicals and recycled back to the terminal
buttons, where they are reassembled and reused
Reuptake: pg 55
Some drugs, such as Prozac, interfere with the reuptake process
Examples of Neurotransmitters
(chart pg 57)
Acetylcholine
Dopamine
Serotonin
Glutamate
Endorphins
Norepinephrine
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Plasticity: The nervous system’s ability to adapt or change as the result of experience.
Glial Cells: pg 74
--Also for the myelin sheath, a fatty insulation around many axons in the brain and spinal chord
Some disease, such as multiple sclerosis, attack the myelin sheath
Nervous System: pg 59
TWO MAIN BUILDING BLOCKS OF THE NERVOUS SYSTEM
1. Neurons with their amazing plasticity
2. Glial cells, which protect neurons and help spread neural messages
Central Nervous System: pg 59
Reflex: pg 61
Peripheral Nervous System: pg 59
Consists of the Somatic and Autonomic nervous systems
A. Somatic Nervous System: pg 59
B. Autonomic Nervous System: pg 59
1. Sympathetic Division of the ANS: pg 59
Examples: Speaking in front of the class
2. Parasympathetic Division of the ANS: pg 60
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The Endocrine System
p.62
The Endocrine System: pg 62
--Under normal conditions, the ES works with the parasympathetic nervous system
--In a crisis, the ES shifts into a new mode, working with the sympathetic nervous system
Hormone: pg 62
Pituitary Gland: pg 63
Agonist: pg 57-58
Antagonist: pg 57-58
3B: THE BRAIN p. 66-91
--------------------------------------------------------------------------------------Key Question:
Core Concept:
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THREE LAYERS OF THE BRAIN
1. Brain Stem: pg 69-71
Medulla: pg 69
Pons: pg 69
Reticular Formation: pg 69-70
Thalamus: pg 70
Directs nearly all the brain’s incoming and outgoing sensory and motor traffic
Cerebellum: pg 70-71
Responsible for coordinated movements
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2. Limbic System: pg 71
Hippocampus: pg 71
Amygdala: pg 71
Hypothalamus: pg 72
3. Cerebrum: pg 74-79
Cerebral Cortex: pg 74
The outer layer of the cerebrum
--Involved in complex mental processes
The Four Lobes of the Cerebral Cortex
1. Frontal Lobes: pg 74
Movement, speech, abstract thought
Motor Cortex: pg 75
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2.Parietal Lobes: pg 74 Sensations of touch, body posture, hearing
Somatosensory Cortex:
pg 77
1. Serves as primary processing area for the sensations of touch, temperature, pain
and pressure from all over the body
2. Relates this information to a mental map of the body to help you locate the
sources of the sensations.
Right Hemisphere’s Parietal Lobes:
Allows us to locate the positions of objects in a three-dimensional space
Left Hemisphere’s Parietal Lobes:
Specializes in locating the source of speech sounds, such as when someone says your name
Also works with the temporal lobe to extract meaning from speech and writing
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3. Occipital Lobes: pg 74 Vision
Visual Cortex: The visual processing areas of the cortex in the occipital and temporal lobes
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4. Temporal Lobes: pg 74 Hearing, smell, vision
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Association Areas: pg 78-79
--The largest proportion of the human cortex is devoted to integrating and interpreting information gathered
from the sensory parts of the brain. Collectively, these regions re known as the association cortex
Corpus Callosum: pg 84
Cerebral Dominance:
The tendency for each hemispheres to take charge of different tasks, but BOTH
hemispheres always work together to produce thoughts, feelings, and behaviors
Left Hemisphere
Right Hemisphere
Regulation of positive emotions
Controls muscles used in speech
Controls sequence of movements
Spontaneous speaking and writing
Memory for words and numbers
Understanding speech and writing
uses logic
detail oriented
facts rule
words and language
present and past
math and science
can comprehend
order/pattern perception
knows object name
reality based
forms strategies
practical
safe
Regulation of negative emotions
Response to simple commands
Memory for shapes and music
Interpreting spatial relationships and
visual images
uses feeling
"big picture" oriented
imagination rules
symbols and images
present and future
philosophy & religion
can "get it" (i.e. meaning)
believes
appreciates
spatial perception
knows object function
fantasy based
presents possibilities
impetuous
risk taking
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3C: GENETICS, EVOLUTIONARY PSYCHOLOGY, AND BEHAVIOR pg 94-110
Genome:
Phenotype:
DNA:
deoxyribonucleic acid
Gene:
\
Chromosome:
46 chromosomes - 23 pairs – half from mother-half from father
Sex Chromosome:
One X from mother….X (for females) or Y (for males) from father
Father’s chromosomes determines sex
XX = female XY = male
Does heredity determine our psychological destiny?
Heredity never acts alone…both heredity and environment always work together to influence behavior and mental processes.
---------------------------------------------------------------------------------------------Key Question:
Core Concept:
Evolution:
Natural Selection:
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