2.1-2.3
2.1- Your Nervous System is the Basis of Your Mental Activity and Behavior
-The nervous system is a network of billions of cells in your brain and your body.
-It has 3 basic functions:
● Receives sensory input from the world through vision, hearing, smell, touch, and taste
● Processes this information in the brain by paying attention to it, perceiving it, and remembering it
● Responds to information by acting on it
-These 3 functions are a result of processing in two divisions of the nervous system:
● The central nervous system consists of nerve cells in the brain and the spinal cord
● The peripheral nervous system consists of the nerve cells outside the brain and spinal cord
-Neurons receive, integrate, and transmit information in the nervous system
● These neurons communicate with other specific neurons, forming networks
-Four parts of the neuron allow it to communicate:
● Dendrites- short, branchlike extensions of the cell body; receive signals from neighboring neurons
● Cell Body- collects and integrates information received from thousands of other neurons
● Axon- long, narrow outgrowth of the cell body; electrical impulses are transmitted after information is integrated- can vary in
length depending on how far it has to travel
● Terminal Buttons- knoblike structure; release chemical signals from the neuron to the synapse
-Synapse- gap between one neuron's terminal buttons and another's dendrites; where communication occurs-release of
neurotransmitters
-Neurotransmitters- chemicals that carry signals from one neuron to another
-Presynaptic Neurons- send the signal by releasing neurotransmitters from their axons
-Postsynaptic Neurons- receive the signal when neurotransmitters bind to the receptions on their dendrites
● Postsynaptic neurons produce two types of signals:
-Excitatory Signals- increase the likelihood that the neuron will fire an action potential- positively charged ions
-Inhibitory Signals- inhibit the neuron and decrease the likelihood that the neuron will fire an action potential- negatively charge
ions
Two major ways in which neurotransmitters are removed from the synapse:
● Reuptake- reabsorbing neurotransmitters into the presynaptic neuron
● Enzyme Degradation- involves the breaking down of neurotransmitters
2.2- Neurons Communicate with Each Other in Your Nervous System
-At every moment of your life, neurons are always communicating with each other. Without neural communication, you would not be
able to see, smell, hear, taste, or feel.
-Neural communication is electrochemical:
● Electrical- information is carried from the cell body to the synapse via electrical neural impulses called action potentials
● Chemical- communication between two neurons depends on the release of chemicals called neurotransmitters
,-Some people experience a breakdown in this neural communication. This can lead to diseases like Multiple Sclerosis (MS). This affects
the brain and spinal cord, usually resulting in inability to control your movements.
-Phases of neural communication:
● Transmission Phase- electrical signals created in the cell body travel along the axon and neurotransmitters are released from t
terminal buttons to the synapse
● Reception Phase- dendrites of other neurons receive these signals from sending neurons
● Integration Phase- neurons asses and integrate these upcoming signals
-The neuron is covered with a semipermeable membrane- ions move across. This regulates the neuron's electrical activity.-neurons a
electric
● When ions move across the membrane, this drives the neural impulse or action potential.
-The inside of a neuron has a more negative charge than the outside. When nothing happens, the neuron is in the resting state- nothin
is happening. When the neuron is stimulated by other neurons around it, it fires an action potential down the axon to the terminal
buttons, where neurotransmitters are released to the synapse.
● Produced by the sudden rush of sodium ions into the cell.- this depolarizes the neuron, the peak is reached when no more
sodium ions can enter, then the neuron repolarizes as potassium ions that rush out of the neuron
● The electrical signal that travels along the axon and leads to the release of neurotransmitters in to synapse.
● The action potential is all or nothing- it doesn't send just a little bit
● The action potential always depolarizes to the same voltage, never more or less
● It can not fire immediately after firing, it needs a "cool down" period- the refractory period
-The action potential is able to travel down the axon so fast because of the myelin sheath- a fatty layer that insulates the axon
2.3- Neurotransmitters Influence your Mental Activity and Behavior
-There are many types of neurotransmitters that all affect different types of mental activity and/or behavior.
Neurotransmitters are manufactured in presynaptic neurons which also have a way to inactivate them
Receptors for the chemical are located on the postsynaptic neuron and mediate the response of that neuron
● Acetylcholine- motor control over muscles, attention, memory, learning, sleeping
● Norepinephrine- arousal and alertness
● Serotonin- emotional states, impulse control, dreaming- many different roles because it has many different receptors
● Dopamine- reward and motivation, motor control over voluntary movement
● GABA- inhibition of action potentials, anxiety reduction, intoxication- inhibitory
● Glutamate- enhancement of action potentials, learning, memory- excitatory
● Endorphins- pain reduction, reward
-Drugs can alter how neurotransmitters function:
● Agonists- drugs that enhance the actions of neurotransmitters. These drugs are similar to one of the neurotransmitters, so the
brain cannot tell the difference. It attaches to said neurotransmitter and enhances that behavior.
● Antagonists- drugs that inhibit the actions of neurotransmitters. These drugs are also similar to one of the neurotransmitters,
and work the same way, except instead of attaching and enhancing, they block and inhibit. This means that the behavior will b
dulled or completely gone.
2.4-2.7
2.4- Our Understanding of How the Brain Works has Improved Over Time
2.1- Your Nervous System is the Basis of Your Mental Activity and Behavior
-The nervous system is a network of billions of cells in your brain and your body.
-It has 3 basic functions:
● Receives sensory input from the world through vision, hearing, smell, touch, and taste
● Processes this information in the brain by paying attention to it, perceiving it, and remembering it
● Responds to information by acting on it
-These 3 functions are a result of processing in two divisions of the nervous system:
● The central nervous system consists of nerve cells in the brain and the spinal cord
● The peripheral nervous system consists of the nerve cells outside the brain and spinal cord
-Neurons receive, integrate, and transmit information in the nervous system
● These neurons communicate with other specific neurons, forming networks
-Four parts of the neuron allow it to communicate:
● Dendrites- short, branchlike extensions of the cell body; receive signals from neighboring neurons
● Cell Body- collects and integrates information received from thousands of other neurons
● Axon- long, narrow outgrowth of the cell body; electrical impulses are transmitted after information is integrated- can vary in
length depending on how far it has to travel
● Terminal Buttons- knoblike structure; release chemical signals from the neuron to the synapse
-Synapse- gap between one neuron's terminal buttons and another's dendrites; where communication occurs-release of
neurotransmitters
-Neurotransmitters- chemicals that carry signals from one neuron to another
-Presynaptic Neurons- send the signal by releasing neurotransmitters from their axons
-Postsynaptic Neurons- receive the signal when neurotransmitters bind to the receptions on their dendrites
● Postsynaptic neurons produce two types of signals:
-Excitatory Signals- increase the likelihood that the neuron will fire an action potential- positively charged ions
-Inhibitory Signals- inhibit the neuron and decrease the likelihood that the neuron will fire an action potential- negatively charge
ions
Two major ways in which neurotransmitters are removed from the synapse:
● Reuptake- reabsorbing neurotransmitters into the presynaptic neuron
● Enzyme Degradation- involves the breaking down of neurotransmitters
2.2- Neurons Communicate with Each Other in Your Nervous System
-At every moment of your life, neurons are always communicating with each other. Without neural communication, you would not be
able to see, smell, hear, taste, or feel.
-Neural communication is electrochemical:
● Electrical- information is carried from the cell body to the synapse via electrical neural impulses called action potentials
● Chemical- communication between two neurons depends on the release of chemicals called neurotransmitters
,-Some people experience a breakdown in this neural communication. This can lead to diseases like Multiple Sclerosis (MS). This affects
the brain and spinal cord, usually resulting in inability to control your movements.
-Phases of neural communication:
● Transmission Phase- electrical signals created in the cell body travel along the axon and neurotransmitters are released from t
terminal buttons to the synapse
● Reception Phase- dendrites of other neurons receive these signals from sending neurons
● Integration Phase- neurons asses and integrate these upcoming signals
-The neuron is covered with a semipermeable membrane- ions move across. This regulates the neuron's electrical activity.-neurons a
electric
● When ions move across the membrane, this drives the neural impulse or action potential.
-The inside of a neuron has a more negative charge than the outside. When nothing happens, the neuron is in the resting state- nothin
is happening. When the neuron is stimulated by other neurons around it, it fires an action potential down the axon to the terminal
buttons, where neurotransmitters are released to the synapse.
● Produced by the sudden rush of sodium ions into the cell.- this depolarizes the neuron, the peak is reached when no more
sodium ions can enter, then the neuron repolarizes as potassium ions that rush out of the neuron
● The electrical signal that travels along the axon and leads to the release of neurotransmitters in to synapse.
● The action potential is all or nothing- it doesn't send just a little bit
● The action potential always depolarizes to the same voltage, never more or less
● It can not fire immediately after firing, it needs a "cool down" period- the refractory period
-The action potential is able to travel down the axon so fast because of the myelin sheath- a fatty layer that insulates the axon
2.3- Neurotransmitters Influence your Mental Activity and Behavior
-There are many types of neurotransmitters that all affect different types of mental activity and/or behavior.
Neurotransmitters are manufactured in presynaptic neurons which also have a way to inactivate them
Receptors for the chemical are located on the postsynaptic neuron and mediate the response of that neuron
● Acetylcholine- motor control over muscles, attention, memory, learning, sleeping
● Norepinephrine- arousal and alertness
● Serotonin- emotional states, impulse control, dreaming- many different roles because it has many different receptors
● Dopamine- reward and motivation, motor control over voluntary movement
● GABA- inhibition of action potentials, anxiety reduction, intoxication- inhibitory
● Glutamate- enhancement of action potentials, learning, memory- excitatory
● Endorphins- pain reduction, reward
-Drugs can alter how neurotransmitters function:
● Agonists- drugs that enhance the actions of neurotransmitters. These drugs are similar to one of the neurotransmitters, so the
brain cannot tell the difference. It attaches to said neurotransmitter and enhances that behavior.
● Antagonists- drugs that inhibit the actions of neurotransmitters. These drugs are also similar to one of the neurotransmitters,
and work the same way, except instead of attaching and enhancing, they block and inhibit. This means that the behavior will b
dulled or completely gone.
2.4-2.7
2.4- Our Understanding of How the Brain Works has Improved Over Time
