Quiz 4 Nervous System

Neurons have different shapes and sizes depending on their role. A bipolar cell in the retina of the eye collects information from a few inputs and transmits it a short distance to one or more closely spaced neurons. What shape would you predict it to have? Select one: a. A few dendrites and a short axon with one or more terminals b. A dense field of dendrites and a single axon c. both dendrites and axon are highly branched d. Numerous dendrites and a long axon e. A long axon with many axon terminals

a. A few dendrites and a short axon with one or more terminals

In order to maintain the resting potential of the nerve cell membrane, the sodium‒potassium pump keeps the concentration of... Select one: a. K+ inside the cell greater than in the extracellular fluid, and the concentration of Na+ inside the cell lower than outside the cell. b. K+ and Na+ inside the cell lower than in the extracellular fluid. c. negative ions higher outside the cell by pumping negative ions across the membrane. d. Na+ inside the cell greater than outside the cell, and the concentration of K+ inside the cell lower than outside the cell. e. Na+ and K+ inside the cell greater than outside the cell.

a. K+ inside the cell greater than in the extracellular fluid, and the concentration of Na+ inside the cell lower than outside the cell.

Which of the following statements about section 2 of the axon is true? Select one: a. Na+ channels will inactivate at this node and enter a refractory state. b. The speed of the action potential is the same here as in all other axons in the nervous system. c. A loss of signal will occur as the action potential travels to each adjacent node. d. Na+ channels remain open here until the action potential has reached the axon terminal. e. The depolarization caused by the opening of voltage-gated channels does not always cause an action potential here.

a. Na+ channels will inactivate at this node and enter a refractory state.

The electrochemical gradient of a given ion determines the movement of that ion across a plasma membrane. Based on your knowledge of the normal intra- and extracellular concentrations of Na+ and K+ ions across a resting membrane, when both Na+ and K+ voltage-gated channels are opened in response to an action potential you would expect that... Select one: a. Na+ will move into the cell, whereas K+ will move out of the cell. b. Na+ and K+ will both move out of the cell. c. Na+ will move out of the cell but K+ flow will cease. d. Na+ will move out of the cell, whereas K+ will move into the cell. e. Na+ and K+ will both move into the cell.

a. Na+ will move into the cell, whereas K+ will move out of the cell.

In a thin section through brain tissue you see a cell that is wrapped around the axon of a neuron, forming concentric layers of plasma membrane. This cell most likely... Select one: a. supplies nutrients to neurons. b. recycles neurotransmitter in the synapses. c. insulates the axon for rapid conduction of action potentials. d. is a Schwann Cell. e. gives structural support to the axon.

c. insulates the axon for rapid conduction of action potentials.

Which statement is correct? Select one: a. During an action potential, the voltage changes from the resting potential of +50 mV to -60mV, then rapidly returns to the resting potential. b. Once voltage-gated sodium channels open and close, they can be triggered again only after a delay of 1-2 seconds. c. When the inside of a neuron becomes more negative in comparison to its resting condition, its plasma membrane is said to be depolarized. d. At resting potential, most of the sodium channels are closed. e. All the statements are incorrect.

d. At resting potential, most of the sodium channels are closed.

Which of the following cellular conditions is paired incorrectly with its numbered position on the graph? Select one: a. Position 3- Potassium leak channels are open. b. Position 5 - All gated channels are closed c. Position 4 - Na+/K+ pump closes d. Position 3 - Voltage-gated potassium channels are closed. e. Position 1 - Leak channels create resting membrane potential

d. Position 3 - Voltage-gated potassium channels are closed.

A disease in which antibodies destroy myelin produced by oligodendrocytes would most likely cause which of the following? Select one: a. The dendrites of peripheral nerves would not process information from other neurons. b. The blood-brain barrier would be weakened and toxins would easily pass into the brain. c. Action potential conduction in neurons in the central nervous system would be faster. d. Neurons in the brain would be deprived of nutrients e. Neurons in the brain and spinal cord would conduct action potentials more slowly.

e. Neurons in the brain and spinal cord would conduct action potentials more slowly.

Which of the following statements concerning graded potentials is true? Select one: a. They travel long distances in order to generate an action potential. b. They are equivalent to the resting potential of the cell membrane. c. All the statements are false. d. They are self sustaining across the dendrite's membranes. e. They allow a cell to integrate inputs and respond proportionally.

e. They allow a cell to integrate inputs and respond proportionally.

When you decide to mark a particular answer to this question, your nervous system sends the command to your hand to do so. That command is carried into your hand by axons of... Select one: a. afferent neurons. b. sensory neurons. c. interneurons. d. ganglion cells. e. efferent neurons.

e. efferent neurons.