Biological Aspects of Psychology
Chapter 3
Pages 59-79, 80-101
Biological Psychology
The psychological specialty that researches the physical & chemical
changes that cause, & occur in response to, behavior & mental processes
Biology = Destiny ????
How does the brain work?
_________________________
Composed of billions of cells that allow organism to gain info about
inner/outer bodily states & respond accordingly
Info Processing & The Nervous System
1. Input
2. Processing
3. Output
Two types of the Cells of Nervous System
 ________________:
Nerve cells, Send/receive signals
 ________________: “Glue” to hold neurons in place
Features of Neurons
 __________________: Contains cell nucleus; Responsible for cell growth &
maintenance
 __________________: Receive inputs from neighboring neurons & carry
signals to cell body; Have many branches; __________________________
 __________________: Carry signals ___________ from the cell body to
communicate with other neurons; Normally one per neuron; Can be short or
long; _______________________
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


Dendrites (DETECT)
Axons (AWAY)
Myelin sheath
Myelin Sheath: Large cells with myelin carry important information
because depolarization happens faster
Increases ____________________________
Synapses
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► In most case, ___________ carry signals away from the cell body and ________
carry signals toward the cell body.
•
Resting Potential
Neuron’s cell membrane
Semi-permeable barrier: The neuron’s cell membrane lets some chemical
molecules pass through, but blocks others
Channel
Chemical Molecules:
Molecules with (+) charge attracted to those with (-) charge (opposite
attraction)
+
+
+
+
Molecules with the same charge(+)(+) or (-)(-) repelled each other
Resting Potential
•
Neurons have slightly more negative ions inside the cell membrane than outside
Polarization:
Cell pumps (+) charged molecules out through its membrane, making inside of cell
slightly more (-) than outside
POLARIZED AXON
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Electrichemical Potential: Force created drives (+) charged molecules toward
inside of cell
Action Potential
If a neuron is stimulated beyond a certain threshold it will “fire”
 All-or-none firing
 Like a gun shot
When a neuron “fires” electrochemical changes occur with the cell
 These changes are called an action potential
Depolarization:
.
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DEPOLARIZED AXON
How are signals transmitted in Neuron?
The Action Potential
► Channels open when a region of an axon becomes depolarized
 As positively charged molecules rush in, the channels of neighboring
regions open, causing even more positive ions to enter
 This process continues on down the cell toward the axon terminals
ACTION POTENTIAL
Refractory period:
Short rest period between neuron firings when neuron CAN’T fire
Repolarization:
(+) charged molecules pumped back outside the membrane, cell returns
to normal polarized state; at this time, neuron is ready to fire again
REFRACTORY PERIOD & REPOLARIZATION
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In Sum,
►
►
►
►
The axon is polarized.
The axon gets a signal
The axon depolarizes (fires)
Refractory period-Short rest period between action potentials that neuron CAN’T
fire.
► The axon goes back to normal (Repolarized).
How Fast Does Action Potentials go?
How does the action potential get from one neuron
to the next?
Communication between neurons
Snapse
Synaptic gap
Synaptic vesicles
Neurotransmitters
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Receptors
Synaptic Transmission
Classes of Neurotransmitters

Small Molecules
o Acetylcholine
o Norepinephrine
o Serotonin
o Dopamine
o GABA
o Glutamate

Peptides
o Opiates
o Endorphins

Gases
o Nitric oxide
Psychoactive Drugs
Locks and Keys

Psychopharmacology
o Blood-brain barrier:
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o Agonist:
o Antagonist:
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Biological Aspects of Psychology
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Organization of Nervous System
Neural networks
Branches of Nervous System
► Central Nervous System (CNS): _____________________________
 Brain
 Spinal cord
► Peripheral Nervous System (PNS): sensory/motor functions
 ________________________
 ________________________
► Sympathetic
► Parasympathetic
Peripheral Nervous System (PNS)
Somatic Nervous System
Autonomic Nervous System
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Branches of autonomic nervous system
-or-flight
Emotion and autonomic nervous system
► Autonomic Nervous System
 Carry info between brain and organs
 Regulate activities of organs to meet bodily need and to prepare for change
 Associated with physical changes that accompany emotions
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•
Sympathetic Nervous system
•
Parasympathetic nervous system
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Central Nervous System (CNS)
Spinal cord
Afferent
Efferent
Reflexes
Regions of the Brain
Hindbrain: Connects spinal cord with rest of brain
Medulla: Controls blood pressure, heart rate, breathing, & other
vitals
Reticular formation: Controls sleep & arousal; attention
Locus coeruleus: Small nucleus in reticular formation involved in
attention, sleep, & mood; “blue spot”
Cerebellum: Initially believed primary function = coordination of
movement; controls memory, impulse control, language, & higher
cognitive processes
Midbrain: Control automatic behaviors that integrate simple movements
sensory input
Substantia nigra: “black substance;” controls smooth initiation of
movement
Striatum
Forebrain: Responsible for complex behaviors/mental life
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Thalamus: Relay station that connects various parts of brain;
regulates awareness, attention, motivation, & emotion
Hypothalamus: Regulates hunger, thirst, & sex drives
Suprachiasmatic nuclei: Brain’s clock for bio rhythms
Amygdala: Involved in emotional responses such as fear, anger, &
disgust; learning & memory formation; altered in people with PTSD
Hippocampus: Learning & memory formation
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Cerebral Cortex
Cerebral hemispheres
Parietal lobe: touch
Occipital lobe: vision
Frontal lobe: higher level cognitions
Temporal lobe: hearing
Sensory cortex
Visual
Auditory
Somatosensory
Motor cortex
Homunculus
Association cortex
Broca’s area
Wernicke’s area
Aphasia
Contralateral Organization of the Brain
Right hemisphere controls left side of body
Left hemisphere controls right side of body
Contralateral Processing of Sensory Information
Information from right side of body is processed in left hemisphere
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Information from left side of body is processed in right hemisphere
Split Brain Studies
Corpus callosum
When corpus callosum is cut
Sensory inputs are still crossed
Motor outputs are still crossed
Hemispheres can’t exchange data
Lateralization
Left hemisphere
Right hemisphere
Plasticity
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