Suppose you stub your foot on a chair leg. Your foot recoils before you feel any pain. Draw a flowchart of the nerve
pathway that is involved in this reaction. What is this reaction called? How does this reaction protect you?
The pathway that this would take is that your body would detect the chair leg, then initiate an impulse in a sensory neuron,
then activate the spinal cord (interneuron) which activates a motor neuron and causes your muscles to act in a way that
move your foot away from the chair leg and from any harm. This reaction is called the reflex arc and it reacts to protect
you by producing involuntary reflexive behaviours such as the withdrawal reflex in this case so that you can quickly move
your foot away and stop yourself from any further danger
Dopamine is an excitatory neurotransmitter. Cocaine affects a synapse by blocking the reuptake of the
neurotransmitter dopamine by the presynaptic neuron. Explain how cocaine interferes with the neural
transmission across the synapse and the effects of dopamine in the brain.
Since dopamine is an excitatory neurotransmitter, it functions to connect the presynaptic and postsynaptic neuron at the
synapse. Normally, dopamine is released by the presynaptic neuron at the end of an axon. It travels through the synapse
and binds to a ligand-gated Na channel on the postsynaptic neuron. When these Na channels open, it depolarizes the
postsynaptic neuron past the threshold and initiates an action potential. When that is completed, the presynaptic neuron
reuptakes dopamine back into the presynaptic neuron. When Cocaine prevents dopamine from being reabsorbed by
presynaptic neurons, resulting in an increased concentration of dopamine in these synapses. As a result, the natural effect
of dopamine on the postsynaptic neurons is amplified and produces the feeling of euphoria typically experienced by
people who take cocaine.
A neurological disease is characterized by a gradual loss of motor control, jerky movements, and sudden
uncontrolled movements of hands and legs. People with this disease were found to have a degeneration of the
inhibitory neurotransmitters at the synapse. Infer how the decrease in inhibitory neurons could result in the
symptoms of this disease.
As an inhibitory neurotransmitter dampens transmission of nerve signals between the presynaptic and postsynaptic
neurons. It is released by the presynaptic neuron and binds to the receptors on the postsynaptic neuron. The binding of the
inhibitory transmitter hyperpolarizes the postsynaptic neuron by opening ligand-gated K+ channels – K+ travels out of the
cell. This brings the postsynaptic neuron farther from threshold, as a result, prevents an action potential from occurring.
Without inhibitory neurotransmitters to control movement, it can cause action potentials in muscle cells to be initiated
inappropriately. This would make it extremely difficult to stop or otherwise control body movements.
The finger must push the first domino just hard enough to get it to fall. Which response does this represent in a
real neuron? Once the dominoes start to fall, they all fall in succession. How does this action represent the real
neuron?
Part of the all-or-none response. Either the stimulus generates the action potential, or it does not, just as the
domino falls or does not fall. Once the dominoes start to fall in succession, this is similar to propagation of the action
potential along the neuron in a real neuron as action potentials move down a neuron.
Symptoms in some people with Alzheimer may include loss of memory and slower reaction rate. A study of the
brain tissues of people with Alzheimer include a decrease in myelinated neurons. Explain how demyelination of
neurons in the brain is connected to the symptoms of Alzheimer.
pathway that is involved in this reaction. What is this reaction called? How does this reaction protect you?
The pathway that this would take is that your body would detect the chair leg, then initiate an impulse in a sensory neuron,
then activate the spinal cord (interneuron) which activates a motor neuron and causes your muscles to act in a way that
move your foot away from the chair leg and from any harm. This reaction is called the reflex arc and it reacts to protect
you by producing involuntary reflexive behaviours such as the withdrawal reflex in this case so that you can quickly move
your foot away and stop yourself from any further danger
Dopamine is an excitatory neurotransmitter. Cocaine affects a synapse by blocking the reuptake of the
neurotransmitter dopamine by the presynaptic neuron. Explain how cocaine interferes with the neural
transmission across the synapse and the effects of dopamine in the brain.
Since dopamine is an excitatory neurotransmitter, it functions to connect the presynaptic and postsynaptic neuron at the
synapse. Normally, dopamine is released by the presynaptic neuron at the end of an axon. It travels through the synapse
and binds to a ligand-gated Na channel on the postsynaptic neuron. When these Na channels open, it depolarizes the
postsynaptic neuron past the threshold and initiates an action potential. When that is completed, the presynaptic neuron
reuptakes dopamine back into the presynaptic neuron. When Cocaine prevents dopamine from being reabsorbed by
presynaptic neurons, resulting in an increased concentration of dopamine in these synapses. As a result, the natural effect
of dopamine on the postsynaptic neurons is amplified and produces the feeling of euphoria typically experienced by
people who take cocaine.
A neurological disease is characterized by a gradual loss of motor control, jerky movements, and sudden
uncontrolled movements of hands and legs. People with this disease were found to have a degeneration of the
inhibitory neurotransmitters at the synapse. Infer how the decrease in inhibitory neurons could result in the
symptoms of this disease.
As an inhibitory neurotransmitter dampens transmission of nerve signals between the presynaptic and postsynaptic
neurons. It is released by the presynaptic neuron and binds to the receptors on the postsynaptic neuron. The binding of the
inhibitory transmitter hyperpolarizes the postsynaptic neuron by opening ligand-gated K+ channels – K+ travels out of the
cell. This brings the postsynaptic neuron farther from threshold, as a result, prevents an action potential from occurring.
Without inhibitory neurotransmitters to control movement, it can cause action potentials in muscle cells to be initiated
inappropriately. This would make it extremely difficult to stop or otherwise control body movements.
The finger must push the first domino just hard enough to get it to fall. Which response does this represent in a
real neuron? Once the dominoes start to fall, they all fall in succession. How does this action represent the real
neuron?
Part of the all-or-none response. Either the stimulus generates the action potential, or it does not, just as the
domino falls or does not fall. Once the dominoes start to fall in succession, this is similar to propagation of the action
potential along the neuron in a real neuron as action potentials move down a neuron.
Symptoms in some people with Alzheimer may include loss of memory and slower reaction rate. A study of the
brain tissues of people with Alzheimer include a decrease in myelinated neurons. Explain how demyelination of
neurons in the brain is connected to the symptoms of Alzheimer.
