Physiological Psychology Module 1.2 Quiz (John Casada Spring 2019)

Electrical gradients lead to the ____.​

movement of ions to areas having opposite electrical charges

What term describes the difference in voltage that typically exists between the inside and the outside of a neuron?​

resting potential

The action potential of a neuron depends mostly on what movement of ions?​

sodium ions entering the cell

The all-or-none law states that ____.

​a neuron produces an action potential of maximal strength, or none at all

The concentration gradient refers to the ____.​

​difference in distribution for various ions between the inside and outside of the membrane

The speed of an action potential down an unmyelinated axon is best described as ____.​

​faster in thick axons than in thin ones

The function of a myelin sheath is to ____.​

​increase the velocity of transmission along an axon

Which action would depolarize a neuron?​

​increasing membrane permeability to sodium

When a neuron's membrane is at rest, the concentration gradient tends to move sodium ____ the cell and the electrical gradient tends to move it ____ the cell.​

​into; into

According to the all-or-none law, ____.

​once an axon reaches threshold, the amplitude and velocity of an action potential are nearly equal each time

When the potential across a membrane reaches threshold, the sodium channels ____.​

​open to let sodium enter the cell rapidly

When a neuron's membrane is at rest, the concentration gradient tends to move potassium ____ the cell and the electrical gradient tends to move it ____ the cell.​

​out of; into

In the normal course of an action potential, ____.​

​sodium remains much more concentrated outside than inside the neuron

The idea that a neuron's membrane is polarized refers to a difference in electrical potential between ____.​

​the inside and the outside of the membrane

What is one major cause for the resting potential of a neuron's membrane?

​the sodium-potassium pump

Voltage-activated channels are channels for which a change in the voltage across the membrane alters their ____.​

Permeability

What occurs when depolarization is less than the cell's threshold?​

Sodium crosses the membrane only slightly more than usual.

Which of the following describes the transmission of information in a local neuron?​

The signal decreases in strength as it travels.

When a membrane is at rest, what attracts sodium ions to the inside of the cell?​

both an electrical gradient and a concentration gradient

What action tends to open the sodium gates across a neuron's membrane?​

depolarization of the membrane