Exam 8: Neurons: the Matter of the Mind

The neuron requires a certain level of depolarization of its membrane in order to generate an action potential. This level of depolarization is known as the ________.

A nerve impulse does not vary in intensity with regard to the strength of the stimulus. What do we call this phenomenon?

Which of the following is a neurotransmitter that triggers a contraction of a voluntary muscle?

Which of these diseases involves the destruction of the myelin sheath on certain neurons within the brain and spinal cord?

The jumping of a nerve impulse from one node of Ranvier to the next is known as ________.

Immediately after an action potential occurs, the sodium channels close and cannot be reopened. What is this period called?

Leprosy destroys nerve tissue, so an afflicted person is likely to hurt his or her foot without even knowing it. Which types of neurons are likely to be affected?

What are some of the dangers associated with the use of organophosphate pesticides that might be of concern for humans? (Organophosphates inhibit acetylcholinesterase.) What are some ethical concerns related to their use?

The synaptic ________ is the narrow space between two neurons.

Which neurotransmitter appears to be associated with an energizing "good" feeling and is essential in hunger, thirst, and sex drive?

Some drugs modulate the activity of ion channels. For example, Novocain somewhat inhibits the opening of sodium channels. What happens to the threshold of a sensory neuron if this drug is used?

The enzyme that removes the neurotransmitter acetylcholine from synapses after it has been released is known as ________.

The neuron that releases neurotransmitters is known as ________, while the neuron that receives the neurotransmitters is knows as ________.

Look at the accompanying figure. In Step 1 ________ ions enter the neuron, while in Step 2 ________ ions leave the neuron.

________ involves an insufficient amount of several neurotransmitters, such as serotonin, dopamine, and norepinephrine, for extended periods of time.

________ is the name given to the motor neurons that carry information away from the brain or spinal cord.

Which neurotransmitter may function to regulate emotions and is involved in pathways that control complex movements?

Compare and contrast the sensory neurons, motor neurons, and interneurons.

Which one of the following ions outside the neuron would make it very difficult for a depolarization to occur?

Potassium ions are important in the resting membrane potential and the action potential of the nerve and to the contraction of muscle cells. The concentration gradient of potassium ions is critical to both. An excess of potassium outside a neuron or muscle cell would negate the concentration gradient. What would happen if the heart were injected with massive amounts of potassium? Explain your answer.