Chapter 3 - Synapses

Question 1

As the nerve impulse reaches the end of the nerve…

Answer 1

• it is changed to a chemical signal, which crosses the synapse and sets up an electrical impulse in the next neuron.

Question 2

Is there a physical connection between neurons?

Answer 2

No. There is no physical connection between neurons. The presence of a synapse means that a nerve is able to communicate better with several neurons that may go to different locations.

Question 3

How is the nerve impulse in the post-synaptic neuron (second neuron) initiated?

Answer 3

• As the nerve impulse reaches the end of the first neuron, a chemical transmitter substance is released. This transmitter then diffuses across the synapse and binds with receptor molecules on the membrane on the next neuron. This initiates a nerve impulse in the post-synaptic neuron (second neuron).

Question 4

After an impulse had been transmitted across what happens to the chemical transmitter?

Answer 4

• After an impulse has been transmitted across, the chemical transmitter is removed from the synapse (it is taken back up by the neuron or broken down by an enzyme).

Question 5

What are the gaps between neurons called?

Answer 5

• the gaps between the neurons are called synapses, through which messages are transmitted from one neuron to the next.

Question 6

There are many different types of transmitter molecules. These work on different nervous pathways. Give an example of one of these transmitter molecules

Answer 6

• e.g. Serotonin is a transmitter that is important in brain function