Chapter 7 - Web activity

What does saltatory conduction mean?

that the nerve impulse seems to jump from one node to the next—and is regenerated as it speeds along.

As the neurotransmitter crosses the synapse, what happens?

The neurotransmitter causes the channel to open, and this can cause a depolarization of the postsynaptic membrane.

When the action potential reaches the synaptic terminal, what happens?

Calcium ions rush into the presynaptic terminal.

As an action potential is propagated and the voltage-regulated ion gates open and close, what happens?

First the polarity is reversed and then the ions return to their normal electrical state.

Which statement accurately describes the myelin sheath? It prevents saltatory conduction. It allows the nodes of Ranvier to act as an electrical insulator. It speeds up the conduction of nervous impulses. It is found on all axons outside the central nervous system. It is found on dendrites in the central nervous system and prevents crossing over of electrical impulses between the axons and the dendrites.

It speeds up the conduction of nervous impulses.

Which of the following is NOT a method for clearing neurotransmitters from a synapse? They can be enzymatically degraded. They can be taken up into the presynaptic terminal. They can be taken up into the postsynaptic neuron. Neurotransmitters can be incorporated into the membrane and form part of the postsynaptic terminal proteins.

Neurotransmitters can be incorporated into the membrane and form part of the postsynaptic terminal proteins.

When speaking of glial cells, we can correctly say that ________.

Schwann cells are glial cells found outside the brain and spinal cord; oligodendrocytes are glial cells found in the brain and spinal cord

In a neuron at rest, the electrical relationship between the fluid inside the axonal cell membrane (inside the cell) and the fluid outside the membrane (extracellular fluid) is as follows: ________.

The interior is negative relative to the exterior.

How would you best define a synapse?

The synapse is the space between the presynaptic neuron and the postsynaptic neuron.

The part of the nerve cell responsible for origination of the nerve impulse is the ________.

axon hillock, because this is the specific area of the nerve cell that generates the electrical impulse

Name the three principal parts of the nerve cell.

axon, dendrites, cell body

Which of the following is the correct sequence for the electrical transmission of a nerve impulse?

presynaptic neuron, synapse, postsynaptic neuron

In the propagation of an action potential, which voltage-regulated gates open first?

sodium gates

The role of the sodium-potassium pump in the story of the action potential is as follows: ________.

the sodium-potassium pump functions in returning the membrane to its "normal" state after an action potential has been propagated

As an action potential moves along an axon, we could say that ________.

when the signal reaches the axon, the sodium channels open and the sodium ions move down a concentration gradient