Introduction to Psychological Theories -
Summary
Week 3: Chapter 3 – Biology and Behavior
The nervous system’s response to the world around us is responsible for everything we
think, feel, or do. The entire nervous system can be divided into two basic units (figure 3.1,
p.70):
Central Nervous System (CNS) = consists of the brain and the spinal cord, both of
which contain massive numbers of neurons
Peripheral Nervous System (PNS) = consists of all the other nerves cells in the rest of
the body. It has two components:
o Somatic Nervous System (SNS) = involved in voluntary behavior, e.g.,
reaching for an object
o Autonomic Nervous System (ANS) = involved in less voluntary behavior, e.g.,
controlling heart rate.
These two units are anatomically separate, but their functions are highly interdependent.
The PNS sends a variety of information to the CNS, while the CNS organizes and evaluates
that information and then directs the PNS to perform specific behaviors or make bodily
adjustments.
3.1 Neurons are the basic Units of the Nervous System
Neurons = Nerve cells which are the basic units of the nervous system. These cells
receive, integrate, and transmit information in the nervous system.
Human complexity results from the action of billions of neurons. Each neuron communicates
with tens of thousands of other neurons. They communicate selectively with other neurons
to form circuits, or neutral networks. These networks develop through genetic influence,
maturation and experience, and repeated firing.
Neurons are powered by electrical impulses and communicate with each other through
chemical signals.
Reception Integration Transmission
During the reception phase, neurons take in the chemical signals from neighboring neurons.
During integration, incoming signals are assessed. During transmission, neurons pass their
own signals yet to other receiving neurons.
1
,There are two types of neurons:
Sensory neurons = Detect information from the physical world and pass that
information through the brain via the spinal cord.
o Somatosensory nerves = Sensory nerves that provide information from the
skin and muscles.
Motor neurons = Direct muscles to contract or to relax, thereby producing
movement.
Sensory and motor neurons work together to control movement. For instance, when you
want to hold a pen, your brain sends a message via motor neurons to your finger muscles to
move them in a specific way. Receptors in both your skin and muscles send back messages
through sensory neurons to help determine how much pressure is needed to hold the pen.
In addition to performing different functions, neurons also have a wide assortment of shapes
and sizes. A typical neuron has 4 structural regions (figure 3.3, p.72):
Dendrites = Branchlike extensions of the neuron that detect information from other
neurons.
Cell body = The site in the neuron where information from thousands of other
neurons is collected and integrated
Axon = A long, narrow, outgrowth of a neuron by which information is conducted
from the cell body to the terminal buttons.
Terminal buttons = At the end of axons, small nodules that release chemical signals
from the neuron into synapse.
Since neurons do not touch each other, they communicate by sending chemicals into the
synapse and the dendrites of receiving neurons.
Synapse = The gap between the terminal buttons of a sending (presynaptic) neuron
and the dendrites of a receiving (postsynaptic) neuron; it is the site at which chemical
communication occurs between neurons.
3.2 Action Potentials Produce Neutral Communication
Neural communication depends on a neuron’s ability to respond to incoming stimulation.
The neuron responds by changing electrically and then passing along chemical signals to
other neurons.
Action potential (neural firing) = The electrical signal that passes along the axon and
subsequently causes the release of chemicals from the terminal buttons.
Rest van paragraaf doorlezen!
2
,3.3 Neurotransmitters Influence Mental Activity and Behavior
In each terminal button are neurotransmitters, which are stored in the vesicles. When
neurotransmitters are released, they travel across the synapse and attach themselves to
receptors on the postsynaptic neuron.
Neurotransmitters = chemical substances that transmit signals from one neuron to
another.
Receptors = specialized protein molecules on the postsynaptic membrane;
neurotransmitters bind to these molecules after passing across the synapse.
The binding of a neurotransmitter with a receptor can cause ion channels to open or close
more tightly, producing an excitatory or an inhibitory signal in the postsynaptic neuron.
Excitatory signal = encourages the neuron to fire.
Inhibitory signal = discourage the neuron from firing.
There are many kinds of neurotransmitters, but only seven of them are particularly
important in understanding how we think, feel, and behave.
Acetylcholine (ACh) Motor control over muscles
Learning, memory, sleeping, and dreaming
Norepinephrine Arousal, vigilance, and attention
Serotine Emotional states and impulsiveness
Dreaming
Dopamine Reward and motivation
Motor control over voluntary movement
GABA (gamma-aminobutric-acid) Inhibition of action potentials
Anxiety reduction
Glutamate Enhancement of action potentials
Learning and memory
Endorphins Pain reduction
Reward
3.4 The ability to study brain function has improved dramatically
In the early nineteenth century, two neuroanatomists, Gall and Spurzheim, hypothesized
about the effects of mental activity on brain anatomy. They proposed that if a person would
use one mental function more than the other, this function would grow. They also believed
that by carefully feeling the skull, one could describe the personality of the individual.
Phrenology = each region of the skull is associated with a feature. Each association is
meant to reflect a process occurring in the brain under the skull.
3
, Nowadays, psychologists use other methods to collect data about the ways people’s bodies
respond to particular tasks or events. There are several ways to measure brain activity:
Electroencephalograph (EEG) = measures the brain’s electrical activity.
Positron Emission Tomography (PET) = scans the brain’s metabolic activity by
injecting radioactive substance into the body.
Magnetic Resonance Imaging (MRI) = Produces a high-resolution image of the brain.
A magnetic field is used to momentarily disrupt the brain’s magnetic force. Energy is
released from the brain tissue in a form that can be measured by detectors
surrounding the brain.
Functional Magnetic Resonance Imaging (fMRI) = Maps mental activity by assessing
the blood’s oxygen level in the brain.
Transcranial Magnetic Stimulation (TMS) = Momentarily disrupts the brain activity in
a specific brain region. This is a powerful tool for examining which brain regions are
necessary for specific psychological functions. Downside of this method is that it can
be used only for short durations.
3.5 The Brain Stem Houses the Basic Programs of Survival
The spinal cord is a rope of neural tissue. Its most important function is to carry sensory
information up to the brain and carry motor signals from the brain to the body parts below
to initiate action. The spinal cord is seen to be composed of two distinct tissue types:
Gray matter = dominated by neuron’s cell bodies
White matter = consists mostly of axons and fatty myelin sheaths that surround
them.
In the base of the skull, the spinal cord thickens and becomes more complex as it transforms
into the brain stem. The brain stem (figure 3.20, p.85) consists of the medulla oblongata, the
pons, and the midbrain. It houses the nerves that control the most basic functions of
survival, such as heart rate, breathing, swallowing, urinating, etc. It also performs functions
for the head like those that the spinal cord performs for the rest of the body.
Reticular formation = A network of neurons in the brain stem. It projects up into the
cerebral cortex and affects general alertness. It is also involved in inducing and
terminating the different stages of sleep.
Cerebellum (figure 3.21, p. 85) = a large, convoluted protuberance at the back of the
brain stem; it is essential for coordinated movement and balance. The most obvious
4
Summary
Week 3: Chapter 3 – Biology and Behavior
The nervous system’s response to the world around us is responsible for everything we
think, feel, or do. The entire nervous system can be divided into two basic units (figure 3.1,
p.70):
Central Nervous System (CNS) = consists of the brain and the spinal cord, both of
which contain massive numbers of neurons
Peripheral Nervous System (PNS) = consists of all the other nerves cells in the rest of
the body. It has two components:
o Somatic Nervous System (SNS) = involved in voluntary behavior, e.g.,
reaching for an object
o Autonomic Nervous System (ANS) = involved in less voluntary behavior, e.g.,
controlling heart rate.
These two units are anatomically separate, but their functions are highly interdependent.
The PNS sends a variety of information to the CNS, while the CNS organizes and evaluates
that information and then directs the PNS to perform specific behaviors or make bodily
adjustments.
3.1 Neurons are the basic Units of the Nervous System
Neurons = Nerve cells which are the basic units of the nervous system. These cells
receive, integrate, and transmit information in the nervous system.
Human complexity results from the action of billions of neurons. Each neuron communicates
with tens of thousands of other neurons. They communicate selectively with other neurons
to form circuits, or neutral networks. These networks develop through genetic influence,
maturation and experience, and repeated firing.
Neurons are powered by electrical impulses and communicate with each other through
chemical signals.
Reception Integration Transmission
During the reception phase, neurons take in the chemical signals from neighboring neurons.
During integration, incoming signals are assessed. During transmission, neurons pass their
own signals yet to other receiving neurons.
1
,There are two types of neurons:
Sensory neurons = Detect information from the physical world and pass that
information through the brain via the spinal cord.
o Somatosensory nerves = Sensory nerves that provide information from the
skin and muscles.
Motor neurons = Direct muscles to contract or to relax, thereby producing
movement.
Sensory and motor neurons work together to control movement. For instance, when you
want to hold a pen, your brain sends a message via motor neurons to your finger muscles to
move them in a specific way. Receptors in both your skin and muscles send back messages
through sensory neurons to help determine how much pressure is needed to hold the pen.
In addition to performing different functions, neurons also have a wide assortment of shapes
and sizes. A typical neuron has 4 structural regions (figure 3.3, p.72):
Dendrites = Branchlike extensions of the neuron that detect information from other
neurons.
Cell body = The site in the neuron where information from thousands of other
neurons is collected and integrated
Axon = A long, narrow, outgrowth of a neuron by which information is conducted
from the cell body to the terminal buttons.
Terminal buttons = At the end of axons, small nodules that release chemical signals
from the neuron into synapse.
Since neurons do not touch each other, they communicate by sending chemicals into the
synapse and the dendrites of receiving neurons.
Synapse = The gap between the terminal buttons of a sending (presynaptic) neuron
and the dendrites of a receiving (postsynaptic) neuron; it is the site at which chemical
communication occurs between neurons.
3.2 Action Potentials Produce Neutral Communication
Neural communication depends on a neuron’s ability to respond to incoming stimulation.
The neuron responds by changing electrically and then passing along chemical signals to
other neurons.
Action potential (neural firing) = The electrical signal that passes along the axon and
subsequently causes the release of chemicals from the terminal buttons.
Rest van paragraaf doorlezen!
2
,3.3 Neurotransmitters Influence Mental Activity and Behavior
In each terminal button are neurotransmitters, which are stored in the vesicles. When
neurotransmitters are released, they travel across the synapse and attach themselves to
receptors on the postsynaptic neuron.
Neurotransmitters = chemical substances that transmit signals from one neuron to
another.
Receptors = specialized protein molecules on the postsynaptic membrane;
neurotransmitters bind to these molecules after passing across the synapse.
The binding of a neurotransmitter with a receptor can cause ion channels to open or close
more tightly, producing an excitatory or an inhibitory signal in the postsynaptic neuron.
Excitatory signal = encourages the neuron to fire.
Inhibitory signal = discourage the neuron from firing.
There are many kinds of neurotransmitters, but only seven of them are particularly
important in understanding how we think, feel, and behave.
Acetylcholine (ACh) Motor control over muscles
Learning, memory, sleeping, and dreaming
Norepinephrine Arousal, vigilance, and attention
Serotine Emotional states and impulsiveness
Dreaming
Dopamine Reward and motivation
Motor control over voluntary movement
GABA (gamma-aminobutric-acid) Inhibition of action potentials
Anxiety reduction
Glutamate Enhancement of action potentials
Learning and memory
Endorphins Pain reduction
Reward
3.4 The ability to study brain function has improved dramatically
In the early nineteenth century, two neuroanatomists, Gall and Spurzheim, hypothesized
about the effects of mental activity on brain anatomy. They proposed that if a person would
use one mental function more than the other, this function would grow. They also believed
that by carefully feeling the skull, one could describe the personality of the individual.
Phrenology = each region of the skull is associated with a feature. Each association is
meant to reflect a process occurring in the brain under the skull.
3
, Nowadays, psychologists use other methods to collect data about the ways people’s bodies
respond to particular tasks or events. There are several ways to measure brain activity:
Electroencephalograph (EEG) = measures the brain’s electrical activity.
Positron Emission Tomography (PET) = scans the brain’s metabolic activity by
injecting radioactive substance into the body.
Magnetic Resonance Imaging (MRI) = Produces a high-resolution image of the brain.
A magnetic field is used to momentarily disrupt the brain’s magnetic force. Energy is
released from the brain tissue in a form that can be measured by detectors
surrounding the brain.
Functional Magnetic Resonance Imaging (fMRI) = Maps mental activity by assessing
the blood’s oxygen level in the brain.
Transcranial Magnetic Stimulation (TMS) = Momentarily disrupts the brain activity in
a specific brain region. This is a powerful tool for examining which brain regions are
necessary for specific psychological functions. Downside of this method is that it can
be used only for short durations.
3.5 The Brain Stem Houses the Basic Programs of Survival
The spinal cord is a rope of neural tissue. Its most important function is to carry sensory
information up to the brain and carry motor signals from the brain to the body parts below
to initiate action. The spinal cord is seen to be composed of two distinct tissue types:
Gray matter = dominated by neuron’s cell bodies
White matter = consists mostly of axons and fatty myelin sheaths that surround
them.
In the base of the skull, the spinal cord thickens and becomes more complex as it transforms
into the brain stem. The brain stem (figure 3.20, p.85) consists of the medulla oblongata, the
pons, and the midbrain. It houses the nerves that control the most basic functions of
survival, such as heart rate, breathing, swallowing, urinating, etc. It also performs functions
for the head like those that the spinal cord performs for the rest of the body.
Reticular formation = A network of neurons in the brain stem. It projects up into the
cerebral cortex and affects general alertness. It is also involved in inducing and
terminating the different stages of sleep.
Cerebellum (figure 3.21, p. 85) = a large, convoluted protuberance at the back of the
brain stem; it is essential for coordinated movement and balance. The most obvious
4
