BIO 231 Quiz 7- 11, 16

Potentiated by the closing of inactivation gates in the voltage-gated sodium ion channels. All of the following are consequences of this in activation except one. Choose the statement that is NOT a consequence of the closing inactivation gates.

This allows for the E-flux or diffusion out of potassium ions resulting in repolarization of the cell. (Note: this is the job of the voltage-gated K+ channel, not Na+ channel)

During the relative refractory period of an action potential, larger than normal stimulus is needed to cause another action potential. This is due to the fact that ���

The voltage-gated potassium ion channels remain open long enough to hyperpolarize the axon dendrite.

If a postsynaptic neuron is stimulated to threshold by spacial summation, this implies that ______

The post synaptic cell has many synapses with many presynaptic neurons. (Spacial summation is repelling different parts of the dendrites to depolarize or hyperpolarize)

What does the CNS use to determine the strength of a stimulus?

frequency of action potentials

The period after initial stimulus when a neuron is not sensitive to another stimulus is the ____

absolute refractory period

Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potential?

voltage-gated channels

Loss of function in the enzyme acetylcholine esterase would result in which of the following?

inability to destroy and remove acetylcholine from the synaptic cleft

Salutary conduction is made possible by _____

The myelin sheath

Select the correct statement regarding chemical synapses.

The synaptic cleft uses the action potential to transmit a chemical signal to the post synaptic cell.

Which of the following correctly describes a graded-potential?

it can have amplitudes of various sizes

Immediately after an action potential has peaked, which of the following channels will open?

voltage gated potassium channels

inhibitory postsynaptic potential, IPSP is associated with _______

hyperpolarization (less likely to send AP)

Which of the following will occur when an excitatory post-synaptic potential or EPSP is being generated on the dendritic membrane?

A single type of channel will open permitting simultaneous flow of sodium and potassium.

The synapse in the photomicrograph was:

Axodendritic

A _____ circuit is a concentrating circuit with many inputs and one output.

Converging