Psych 3 Chapter 1

The all-or-none law states that ____.

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

Glial cells ____.

are smaller but more numerous than neurons in the human brain.

What type of glia helps to synchronize the activity of axons?

astrocytes

A drug that blocks the sodium gates of a neuron's membrane will ____.

block the action potential

Water, oxygen, and ____ most freely flow across a cell membrane.

carbon dioxide

The primary feature of a neuron that prevents the action potential from traveling back from where it just passed is the ____.

concentration gradient

The tree-like branches of a neuron that receive information from other neurons are called _____.

dendrites

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

depolarization of the membrane

The concentration gradient refers to the ____.

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

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

The insulating material that covers many vertebrate axons is called the ____.

myelin sheath

The resting potential is mainly the result of ____.

negatively charged proteins inside the cell

The two basic kinds of cells in the nervous system are _____.

neurons and glia

Santiago Ramon y Cajaldemonstrated that ____.

neurons are separate from one another

The structure that contains a cell's chromosomes is called the ____.

nucleus

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

Neurons differ most strongly from other body cells in their ____.

shape

What structure is composed of two layers of fat molecules that are free to flow around one another?

the membrane

What leads to Korsakoff's syndrome?

thiamine deficiency due to chronic alcoholism