Topic 1 Answers - Q andA PDF

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TOPIC 1 1.

Some dendrites contain additional short outgrowths. What are these outgrowths called? a. Hillocks. b. Dendritic spines. c. Dendritic roots. d. Myelin sheaths. 2. a. b. c. d.

Incoming synapses are primarily found on Dendrites only. Cell bodies only. Axons only. Dendrites and cell bodies.

3. a. b. c. d.

Nodes of Ranvier are Gaps in the myelin of axons. The same as the myelin sheath. The spiny outgrowths on dendrites. Responsible for cell metabolism.

4. a. b. c. d.

A neuron can have any number of Dendrites; axon. Axons; dendrite. Dendrites; cell body. Both a and c are correct

5. a. b. c. d.

Which type of glial cells remove waste material in the nervous system? Microglia. Schwann cells. Oligodendrocytes. Radial glia.

, but no more than one

.

6.

in the brain and spinal cord and in the periphery are specialized types of glia that build the myelin sheaths that surround neurons. a. Oligodendrocytes; Schwann cells. b. Schwann cells; Oligodendrocytes. c. Microglia; Oligodendrocytes. d. Radial glia; Schwann cells. 7. a. b. c. d.

When the neural membrane is at rest, the voltage-gated sodium channels Permit Na+ to pass quickly and easily. Permit K+ to cross instead of Na+. Are closed. Are inactive.

8. The concentration gradient refers to a. The fact that the concentration of ions is greater on the inside of a neuron. b. The fact that the concentration of ions is greater on the outside of a neuron. c. The difference in distribution for various ions between the inside and outside of the membrane. d. The negatively charged proteins inside the cell. 9. a. b. c. d.

Electrical gradients lead to what kind of movements? The general movement of ions into the neuron. The general movement of ions out of the neuron. The movement of ions to areas having the same electrical charge. The movement of ions to areas having the opposite electrical charge.

10. A membrane produces an action potential whenever the potential across it reaches what level? a. The resting potential. b. -90mV. c. The threshold of excitation. d. The refractory period. 11. a. b. c. d.

Hyperpolarization is Increased polarization. Decreased polarization. The threshold of the cell. The resting potential of the cell.

12. a. b. c. d.

At what point do the Na+ channels begin to close? At the peak of the action potential. When the threshold is reached. At the end of the relative refractory period. When the concentration gradient for Na+ is reached.

13. Which of the following would depolarize a neuron? a. Decreasing the membrane’s permeability to Ca2+. b. Increasing the membrane’s permeability to K+. c. Decreasing the membrane’s permeability to Na+. d. Increasing the membrane’s permeability to Na+. 14. a. b. c. d.

A drug that decreases the flow of K+ through the membrane would Block action potentials. Increase the threshold of the membrane. Slow the return of the membrane to its resting state. Cause the membrane to be hyperpolarized....