Physiological Psychology
PHYP2111 || A.Y. 2025-2026
Chapter 1: The Biological Approach To Psychology Mendelian Genetics
The Biological Approach to Behavior ● 19th century monk Gregor Mendel demonstrated that
inheritance occurs through genes
● Leibniz (1714) posed in regards to the universe: ● Genes are aligned along chromosomes (strands of genes)
○ “Why is there something rather than nothing?” and come in pairs
● The universe could have taken on many different forms; ● A gene is a portion of a chromosome and is composed of
very few could have supported life deoxyribonucleic acid (DNA)
● We may never know why the universe is the way it is ● DNA serves as a model for the synthesis of ribonucleic
acid (RNA)
● Chalmers (1995) proposes the “hard problem” ● RNA is a single strand chemical that can serve as a
○ Given a universe of matter and energy, why is template/ model for the synthesis of proteins
there such a thing as consciousness? ● Proteins determine the development of the body by:
● A question of the relationship between physics and ○ Forming part of the structure of the body
psychology ○ Serving as enzymes, biological catalysts that
regulate chemical reactions in the body
● Biological explanations of behavior raise the issue of the
relationship between mental activity and the brain also
known as the “mind-body” or “mind-brain problem”
● The “mind-brain problem” has a variety of explanations
● Biological psychology: the study of the physiological,
evolutionary and developmental mechanisms of behavior
and experience
● A strong emphasis is placed upon brain functioning
● Brain functioning can be explained at a more microscopic
level in terms of neuron and glia activity ● Homozygous, for, a gene means that a person has an
● Neurons and glia somehow produce an enormous wealth identical pair of genes on the two chromosomes
of behavior and experience ● Heterozygous, for a gene, means that a person has an
unmatched pair of genes on the two chromosomes
Biological explanations of behavior fall into four categories: ● Genes are either dominant, recessive, or intermediate
● Physiological: relates a behavior to the activity of the ○ Examples: eye color, ability to taste PTC
brain and other organs ● A dominant gene shows a strong effect in either the
● Ontogenetic: describes the development of a structure or homozygous or heterozygous condition
behavior ● A recessive gene shows its effect only in the homozygous
● Evolutionary: reconstructs evolutionary history of a condition
behavior or structure ● Examples such as PTC and hair color can be misleading
● Functional: describes why a structure or behavior evolved ○ Implies that a single gene combination
as it did completely controls a characteristic, but this is
not true
Career Opportunities ● Some genes are only expressed partly: in some cells and
not others or only under certain circumstances
● Careers related to biological psychology fall into two ● Types of genes include:
categories: ○ Autosomal genes: all other genes except for
○ Research: usually requires a Ph.D. sex- linked genes
○ Therapy ○ Sex-linked genes: genes located on the sex
● See Table 1.1 in text for fields of specialization chromosomes
● In mammals, the sex chromosomes are designated X & Y
Genetics and Behavior ○ Females have two X chromosomes (XX)
○ Males have an X and a Y chromosome (XY)
● Both genes and environment interact to shape human ● During reproduction:
behavior ○ Females contribute an X chromosome
● The fundamental issue is how much a role each factor ○ Males contribute either an X or a Y
plays in shaping human behaviors chromosome that determines the sex of the
○ Examples: psychological disorders, weight gain, child
personality, sexual orientation
prepared by: cybct
, Physiological Psychology
PHYP2111 || A.Y. 2025-2026
● If an X chromosome is contributed by the male, the ○ Environmental interventions can modify PKU
offspring is female ● Genes do not directly produce behaviors
● If a Y chromosome is contributed by the male, the ● Genes produce proteins that increase the probability that
offspring will be male a behavior will develop under certain circumstances
● The human Y chromosome has genes for 27 proteins ● Genes can also have an indirect effect
● The human X chromosome has genes for approximately ● Genes can alter your environment by producing behaviors
1500 proteins or traits that alter how people in your environment react
● Thus, sex-linked genes usually refer to X-linked genes: to you
e.g., red-green color deficiency)
● Sex-limited genes are genes that are present in both The Evolution of Behavior
sexes but mainly have an effect on one sex (chest hair,
breast size, etc.) ● Evolution refers to a change in the frequency of various
● Genes change in several ways: genes in a population over generations
○ Mutation: a heritable change in a DNA molecule ● Regardless if helpful or harmful to the species
○ Microduplication/microdeletion: part of a ● Evolution attempts to answer two questions:
chromosome that might appear once might ○ How did some species evolve?
appear twice or not at all ○ How do species evolve?
○ Example: some researchers believe ● How species did evolve involves the tentative
schizophrenia might be a result of construction of “evolutionary trees”
microduplications and microdeletions of ● How species do evolve rests upon some assumptions:
brain-relevant genes ○ Offspring generally resemble their parents for
● Epigenetics: a field that is concerned with changes in genetic reasons
gene expression without the modification of the DNA ○ Mutations, recombination, and
sequence microduplications of genes introduce new
● Some genes are active only at a certain point in one’s life, heritable variations
a certain time of day, etc. ○ Certain individuals successfully reproduce more
● Changes in gene expression are central to learning and than others do
memory ● Artificial selection refers to choosing individuals with
● Epigenetic differences are a likely explanation for desired traits and making them parents of the next
differences between monozygotic “identical” twins generation
● What you do at any moment not only affects you now, but ● According to Darwin, nature also selects, and successful
produces epigenetic effects that alter gene expressions individuals’ genes will be prevalent in later generations
for a longer period of time ● Common misconceptions about evolution include the
● Experiences alter the activity of genes following:
○ Lamarckian evolution: “The use or disuse of
Heredity and Environment some structure or behavior causes an increase
or decrease in that behavior.”
● Almost all behaviors have both a genetic component and ○ “Humans have stopped evolving.”
an environmental component ○ “Evolution means improvement.”
● Researchers study monozygotic (“from one egg”) and ○ “Evolution acts to benefit the individual or the
fraternal (“from two eggs”) twins to infer contributions of species.”
heredity and environment ● Evolutionary psychology focuses upon functional and
● Researchers also study adopted children and their evolutionary explanations of how behaviors evolved
resemblance to their biological parents to infer hereditary ○ Assumes that behaviors characteristic of a
influences species have arisen through natural selection
● Heritability refers to how much characteristics depend and provide a survival advantage
on genetic differences ■ Examples: differences in
● Researchers have found evidence for heritability in almost peripheral/color vision, sleep
every behavior they have tested mechanisms in the brain, eating
● Heritability of a certain trait is specific to a given habits, temperature regulation
population ● Some behaviors are more debatable regarding the
● Strong environmental influences may cause genetic influence of natural selection
influences to have less of an effect ● Examples include:
● Traits with a strong hereditary influence can be modified ○ Life span length
by environmental intervention ○ Gender differences in sexual promiscuity
○ e.g., PKU: a genetic inability to metabolize the ○ Altruistic behavior: a behavior that benefits
amino acid phenylketonuria someone other than the actor
prepared by: cybct
, Physiological Psychology
PHYP2111 || A.Y. 2025-2026
■ Altruism is hard to find outside of Chapter 2: Neurons and Action Potentials
humans
● A gene only spreads if individuals with it reproduce more Anatomy of Neurons and Glia
than individuals without it
● A gene that benefits the species but not the individual ● The human nervous system is comprised of two kinds of
dies out with that individual cells:
● Group selection is a controversial hypothesis that states ○ Neurons
that altruistic groups survive better than less cooperative ○ Glia
ones ● The human brain contains approximately 100 billion
● Kin selection is the favored explanation: selection for a individual neurons
gene that benefit’s the individual’s relatives
● Reciprocal altruism is the idea that individuals help those Historical Perspective
that will return the favor
● Building a reputation for helpfulness only works if others ● In the late 1800s, Santiago Ramon y Cajal was the first to
are willing to cooperate with you demonstrate that:
○ Individual cells in the nervous system remained
The Use of Animals in Research separate.
○ They did not grow into each other as previously
● Animal research is an important source of information for believed.
biological psychology but remains a highly controversial
topic Structures Found in Neurons
● Animal research varies on the amount of stress and/ or
pain that is caused to the animal itself ● Like other cells in the body, neurons contain:
○ Membrane
Reasons for Animal Research ○ Nucleus
○ Mitochondria
● Reasons for studying animals include: ○ Ribosomes
○ The underlying mechanisms of behavior are ○ Endoplasmic reticulum
similar across species and often easier to study
in nonhuman species Membrane and Cell Components
○ We are interested in animals for their own sake
○ What we learn about animals sheds light on ● Membrane: Separates the inside of the cell from the
human evolution outside environment.
○ Some experiments cannot use humans because ● Nucleus: Contains the chromosomes.
of legal or ethical reasons ● Mitochondrion: Performs metabolic activities and
provides energy.
● Ribosomes: Sites for synthesizing new protein molecules.
● Endoplasmic Reticulum: Transports newly synthesized
proteins.
The Ethical Debate
Neurons
● Opposition to animal research varies:
○ “Minimalists” favor firm regulation on research ● Neuron cells are similar to other cells of the body but
and place consideration upon the type of animal have a distinctive shape
used and the amount of stress induced ○ Motor Neurons: Soma in the spinal cord,
○ “Abolitionists” maintain that all animals have the receives excitation, conducts impulses along its
same rights as humans and any use of animals is axon to muscles.
unethical ○ Sensory Neurons: Specialized at one end to be
● Justification for research considers the amount of benefit sensitive to specific types of stimulation (e.g.,
gained compared to the amount of distress caused to the touch, light).
animal
○ No clear dividing line exists
● Colleges and research institutions in the United States
are required to have an Institutional Animal Care and Use
Committee
○ Oversees and determine acceptable procedures
prepared by: cybct
, Physiological Psychology
PHYP2111 || A.Y. 2025-2026
Major Components of Neurons The Blood-Brain Barrier
● Dendrites:
○ Branching fibers; lined with synaptic receptors ● Mechanism surrounding the brain blocking most
for information intake into the neuron chemicals:
○ Some dendrites also contain dendritic spines ● The immune system destroys damaged or infected cells
that further branch out and increase the surface throughout the body
area of the dendrite ● Because neurons in the brain generally do not regenerate,
○ The greater the surface area of the dendrite, the it is vitally important for the blood brain barrier to block
more information it can receive incoming viruses, bacteria, or other harmful material
● Soma/Cell Body: from entering
● Active Transport:
○ Contains nucleus, mitochondria; responsible for
○ Protein-mediated process pumping chemicals
metabolic work.
from blood into the brain.
● Axon:
○ Allows certain nutrients like glucose and some
○ Thin fiber transmitting nerve impulses; may be
hormones to pass.
covered by myelin sheath with interruptions in
○ Glucose, certain hormones, amino acids, and a
the sheath known as nodes of Ranvier
few vitamins are brought into the brain via
● Presynaptic Terminals:
active transport
○ Endpoints of axon for chemical communication
○ The blood-brain barrier is essential to health,
with other neurons.
but can pose a difficulty in allowing chemicals
such as chemotherapy for brain cancer to pass
Neuron Types and Their Functions
the barrier
● Afferent Axon: Brings information into a structure. Nourishment in Vertebrate Neurons
● Efferent Axon: Carries information away from a structure.
● Interneurons or Intrinsic Neurons: Dendrites and axons ● Vertebrate Neurons primarily depend on glucose, which
are contained within a single structure. can pass through the blood-brain barrier.
● Oxygen is essential; the brain uses about 20% of the
Variability in Neurons body's oxygen.
● The shape determines connectivity with other neurons. ● Thiamine (Vitamin B1) is necessary to utilize glucose:
● The function is closely related to the shape of a neuron ○ Prolonged deficiency can lead to Korsakoff’s
○ Example: Purkinje cells of the cerebellum syndrome from chronic alcoholism, resulting in
branch extremely widely within a single plane severe memory impairment.
Glia (Neuroglia) The Nerve Impulse
● Glia (neuralgia) are the other major components of the
nervous system. ● A nerve impulse is the electrical message that is
● Types of glia in the brain: transmitted down the axon of a neuron
○ Astrocytes: Synchronize axon activity and ● Not directly traveling but regenerating at points along the
uptake chemicals (from axon) axon.
○ Microglia: Remove waste and harmful ● Speed ranges from less than 1 m/s to 100 m/s depending
microorganisms. on the neuron.
○ Oligodendrocytes: Build myelin sheath in the ● A touch on the shoulder reaches the brain more quickly
brain and spinal cord that surrounds and than a touch on the foot
insulates certain vertebrate axons
○ Schwann Cells: Build myelin sheath in the The brain isn’t wired to detect tiny timing differences in touch
peripheral body. signals. However, precise timing is crucial for vision to track
○ Radial Glia: guide the migration of neurons and movement accurately. The nervous system's impulse control is
the growth of their axons and dendrites during perfectly suited for efficient information transfer.
embryonic development
The Resting Potential of the Neuron
When embryonic development finishes, most radial glia
differentiate into neurons and a smaller number differentiate into ● The membrane of a neuron maintains an electrical
astrocytes and oligodendrocytes gradient
○ A difference in the electrical charge inside and
outside of the cell
● This is also known as polarization
prepared by: cybct
PHYP2111 || A.Y. 2025-2026
Chapter 1: The Biological Approach To Psychology Mendelian Genetics
The Biological Approach to Behavior ● 19th century monk Gregor Mendel demonstrated that
inheritance occurs through genes
● Leibniz (1714) posed in regards to the universe: ● Genes are aligned along chromosomes (strands of genes)
○ “Why is there something rather than nothing?” and come in pairs
● The universe could have taken on many different forms; ● A gene is a portion of a chromosome and is composed of
very few could have supported life deoxyribonucleic acid (DNA)
● We may never know why the universe is the way it is ● DNA serves as a model for the synthesis of ribonucleic
acid (RNA)
● Chalmers (1995) proposes the “hard problem” ● RNA is a single strand chemical that can serve as a
○ Given a universe of matter and energy, why is template/ model for the synthesis of proteins
there such a thing as consciousness? ● Proteins determine the development of the body by:
● A question of the relationship between physics and ○ Forming part of the structure of the body
psychology ○ Serving as enzymes, biological catalysts that
regulate chemical reactions in the body
● Biological explanations of behavior raise the issue of the
relationship between mental activity and the brain also
known as the “mind-body” or “mind-brain problem”
● The “mind-brain problem” has a variety of explanations
● Biological psychology: the study of the physiological,
evolutionary and developmental mechanisms of behavior
and experience
● A strong emphasis is placed upon brain functioning
● Brain functioning can be explained at a more microscopic
level in terms of neuron and glia activity ● Homozygous, for, a gene means that a person has an
● Neurons and glia somehow produce an enormous wealth identical pair of genes on the two chromosomes
of behavior and experience ● Heterozygous, for a gene, means that a person has an
unmatched pair of genes on the two chromosomes
Biological explanations of behavior fall into four categories: ● Genes are either dominant, recessive, or intermediate
● Physiological: relates a behavior to the activity of the ○ Examples: eye color, ability to taste PTC
brain and other organs ● A dominant gene shows a strong effect in either the
● Ontogenetic: describes the development of a structure or homozygous or heterozygous condition
behavior ● A recessive gene shows its effect only in the homozygous
● Evolutionary: reconstructs evolutionary history of a condition
behavior or structure ● Examples such as PTC and hair color can be misleading
● Functional: describes why a structure or behavior evolved ○ Implies that a single gene combination
as it did completely controls a characteristic, but this is
not true
Career Opportunities ● Some genes are only expressed partly: in some cells and
not others or only under certain circumstances
● Careers related to biological psychology fall into two ● Types of genes include:
categories: ○ Autosomal genes: all other genes except for
○ Research: usually requires a Ph.D. sex- linked genes
○ Therapy ○ Sex-linked genes: genes located on the sex
● See Table 1.1 in text for fields of specialization chromosomes
● In mammals, the sex chromosomes are designated X & Y
Genetics and Behavior ○ Females have two X chromosomes (XX)
○ Males have an X and a Y chromosome (XY)
● Both genes and environment interact to shape human ● During reproduction:
behavior ○ Females contribute an X chromosome
● The fundamental issue is how much a role each factor ○ Males contribute either an X or a Y
plays in shaping human behaviors chromosome that determines the sex of the
○ Examples: psychological disorders, weight gain, child
personality, sexual orientation
prepared by: cybct
, Physiological Psychology
PHYP2111 || A.Y. 2025-2026
● If an X chromosome is contributed by the male, the ○ Environmental interventions can modify PKU
offspring is female ● Genes do not directly produce behaviors
● If a Y chromosome is contributed by the male, the ● Genes produce proteins that increase the probability that
offspring will be male a behavior will develop under certain circumstances
● The human Y chromosome has genes for 27 proteins ● Genes can also have an indirect effect
● The human X chromosome has genes for approximately ● Genes can alter your environment by producing behaviors
1500 proteins or traits that alter how people in your environment react
● Thus, sex-linked genes usually refer to X-linked genes: to you
e.g., red-green color deficiency)
● Sex-limited genes are genes that are present in both The Evolution of Behavior
sexes but mainly have an effect on one sex (chest hair,
breast size, etc.) ● Evolution refers to a change in the frequency of various
● Genes change in several ways: genes in a population over generations
○ Mutation: a heritable change in a DNA molecule ● Regardless if helpful or harmful to the species
○ Microduplication/microdeletion: part of a ● Evolution attempts to answer two questions:
chromosome that might appear once might ○ How did some species evolve?
appear twice or not at all ○ How do species evolve?
○ Example: some researchers believe ● How species did evolve involves the tentative
schizophrenia might be a result of construction of “evolutionary trees”
microduplications and microdeletions of ● How species do evolve rests upon some assumptions:
brain-relevant genes ○ Offspring generally resemble their parents for
● Epigenetics: a field that is concerned with changes in genetic reasons
gene expression without the modification of the DNA ○ Mutations, recombination, and
sequence microduplications of genes introduce new
● Some genes are active only at a certain point in one’s life, heritable variations
a certain time of day, etc. ○ Certain individuals successfully reproduce more
● Changes in gene expression are central to learning and than others do
memory ● Artificial selection refers to choosing individuals with
● Epigenetic differences are a likely explanation for desired traits and making them parents of the next
differences between monozygotic “identical” twins generation
● What you do at any moment not only affects you now, but ● According to Darwin, nature also selects, and successful
produces epigenetic effects that alter gene expressions individuals’ genes will be prevalent in later generations
for a longer period of time ● Common misconceptions about evolution include the
● Experiences alter the activity of genes following:
○ Lamarckian evolution: “The use or disuse of
Heredity and Environment some structure or behavior causes an increase
or decrease in that behavior.”
● Almost all behaviors have both a genetic component and ○ “Humans have stopped evolving.”
an environmental component ○ “Evolution means improvement.”
● Researchers study monozygotic (“from one egg”) and ○ “Evolution acts to benefit the individual or the
fraternal (“from two eggs”) twins to infer contributions of species.”
heredity and environment ● Evolutionary psychology focuses upon functional and
● Researchers also study adopted children and their evolutionary explanations of how behaviors evolved
resemblance to their biological parents to infer hereditary ○ Assumes that behaviors characteristic of a
influences species have arisen through natural selection
● Heritability refers to how much characteristics depend and provide a survival advantage
on genetic differences ■ Examples: differences in
● Researchers have found evidence for heritability in almost peripheral/color vision, sleep
every behavior they have tested mechanisms in the brain, eating
● Heritability of a certain trait is specific to a given habits, temperature regulation
population ● Some behaviors are more debatable regarding the
● Strong environmental influences may cause genetic influence of natural selection
influences to have less of an effect ● Examples include:
● Traits with a strong hereditary influence can be modified ○ Life span length
by environmental intervention ○ Gender differences in sexual promiscuity
○ e.g., PKU: a genetic inability to metabolize the ○ Altruistic behavior: a behavior that benefits
amino acid phenylketonuria someone other than the actor
prepared by: cybct
, Physiological Psychology
PHYP2111 || A.Y. 2025-2026
■ Altruism is hard to find outside of Chapter 2: Neurons and Action Potentials
humans
● A gene only spreads if individuals with it reproduce more Anatomy of Neurons and Glia
than individuals without it
● A gene that benefits the species but not the individual ● The human nervous system is comprised of two kinds of
dies out with that individual cells:
● Group selection is a controversial hypothesis that states ○ Neurons
that altruistic groups survive better than less cooperative ○ Glia
ones ● The human brain contains approximately 100 billion
● Kin selection is the favored explanation: selection for a individual neurons
gene that benefit’s the individual’s relatives
● Reciprocal altruism is the idea that individuals help those Historical Perspective
that will return the favor
● Building a reputation for helpfulness only works if others ● In the late 1800s, Santiago Ramon y Cajal was the first to
are willing to cooperate with you demonstrate that:
○ Individual cells in the nervous system remained
The Use of Animals in Research separate.
○ They did not grow into each other as previously
● Animal research is an important source of information for believed.
biological psychology but remains a highly controversial
topic Structures Found in Neurons
● Animal research varies on the amount of stress and/ or
pain that is caused to the animal itself ● Like other cells in the body, neurons contain:
○ Membrane
Reasons for Animal Research ○ Nucleus
○ Mitochondria
● Reasons for studying animals include: ○ Ribosomes
○ The underlying mechanisms of behavior are ○ Endoplasmic reticulum
similar across species and often easier to study
in nonhuman species Membrane and Cell Components
○ We are interested in animals for their own sake
○ What we learn about animals sheds light on ● Membrane: Separates the inside of the cell from the
human evolution outside environment.
○ Some experiments cannot use humans because ● Nucleus: Contains the chromosomes.
of legal or ethical reasons ● Mitochondrion: Performs metabolic activities and
provides energy.
● Ribosomes: Sites for synthesizing new protein molecules.
● Endoplasmic Reticulum: Transports newly synthesized
proteins.
The Ethical Debate
Neurons
● Opposition to animal research varies:
○ “Minimalists” favor firm regulation on research ● Neuron cells are similar to other cells of the body but
and place consideration upon the type of animal have a distinctive shape
used and the amount of stress induced ○ Motor Neurons: Soma in the spinal cord,
○ “Abolitionists” maintain that all animals have the receives excitation, conducts impulses along its
same rights as humans and any use of animals is axon to muscles.
unethical ○ Sensory Neurons: Specialized at one end to be
● Justification for research considers the amount of benefit sensitive to specific types of stimulation (e.g.,
gained compared to the amount of distress caused to the touch, light).
animal
○ No clear dividing line exists
● Colleges and research institutions in the United States
are required to have an Institutional Animal Care and Use
Committee
○ Oversees and determine acceptable procedures
prepared by: cybct
, Physiological Psychology
PHYP2111 || A.Y. 2025-2026
Major Components of Neurons The Blood-Brain Barrier
● Dendrites:
○ Branching fibers; lined with synaptic receptors ● Mechanism surrounding the brain blocking most
for information intake into the neuron chemicals:
○ Some dendrites also contain dendritic spines ● The immune system destroys damaged or infected cells
that further branch out and increase the surface throughout the body
area of the dendrite ● Because neurons in the brain generally do not regenerate,
○ The greater the surface area of the dendrite, the it is vitally important for the blood brain barrier to block
more information it can receive incoming viruses, bacteria, or other harmful material
● Soma/Cell Body: from entering
● Active Transport:
○ Contains nucleus, mitochondria; responsible for
○ Protein-mediated process pumping chemicals
metabolic work.
from blood into the brain.
● Axon:
○ Allows certain nutrients like glucose and some
○ Thin fiber transmitting nerve impulses; may be
hormones to pass.
covered by myelin sheath with interruptions in
○ Glucose, certain hormones, amino acids, and a
the sheath known as nodes of Ranvier
few vitamins are brought into the brain via
● Presynaptic Terminals:
active transport
○ Endpoints of axon for chemical communication
○ The blood-brain barrier is essential to health,
with other neurons.
but can pose a difficulty in allowing chemicals
such as chemotherapy for brain cancer to pass
Neuron Types and Their Functions
the barrier
● Afferent Axon: Brings information into a structure. Nourishment in Vertebrate Neurons
● Efferent Axon: Carries information away from a structure.
● Interneurons or Intrinsic Neurons: Dendrites and axons ● Vertebrate Neurons primarily depend on glucose, which
are contained within a single structure. can pass through the blood-brain barrier.
● Oxygen is essential; the brain uses about 20% of the
Variability in Neurons body's oxygen.
● The shape determines connectivity with other neurons. ● Thiamine (Vitamin B1) is necessary to utilize glucose:
● The function is closely related to the shape of a neuron ○ Prolonged deficiency can lead to Korsakoff’s
○ Example: Purkinje cells of the cerebellum syndrome from chronic alcoholism, resulting in
branch extremely widely within a single plane severe memory impairment.
Glia (Neuroglia) The Nerve Impulse
● Glia (neuralgia) are the other major components of the
nervous system. ● A nerve impulse is the electrical message that is
● Types of glia in the brain: transmitted down the axon of a neuron
○ Astrocytes: Synchronize axon activity and ● Not directly traveling but regenerating at points along the
uptake chemicals (from axon) axon.
○ Microglia: Remove waste and harmful ● Speed ranges from less than 1 m/s to 100 m/s depending
microorganisms. on the neuron.
○ Oligodendrocytes: Build myelin sheath in the ● A touch on the shoulder reaches the brain more quickly
brain and spinal cord that surrounds and than a touch on the foot
insulates certain vertebrate axons
○ Schwann Cells: Build myelin sheath in the The brain isn’t wired to detect tiny timing differences in touch
peripheral body. signals. However, precise timing is crucial for vision to track
○ Radial Glia: guide the migration of neurons and movement accurately. The nervous system's impulse control is
the growth of their axons and dendrites during perfectly suited for efficient information transfer.
embryonic development
The Resting Potential of the Neuron
When embryonic development finishes, most radial glia
differentiate into neurons and a smaller number differentiate into ● The membrane of a neuron maintains an electrical
astrocytes and oligodendrocytes gradient
○ A difference in the electrical charge inside and
outside of the cell
● This is also known as polarization
prepared by: cybct
