Ch1

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

An electrical gradient

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

Carbon dioxide

In what direction does a local neuron transmit information?

Equally well in any direction

2 basic kinds of cells in nervous system

Neurons & Glia

Santiago Ramon y Cajal demonstrated that

Neurons are separate from one another

Dendrites

are branching fibers that get narrower near their ends

Professor Peach is lecturing in her class about glial cells. She will tell her class that glial cells

are not as well studied as neurons but have been shown to perform many important functions in the nervous system

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

block the action potential

Why is glucose so important to the brain?

glucose is unique and can cross the blood-brain barrier to be used by neurons

Many dendrites contain short outgrowths called spines that

increase the surface area available for synapses

What type of glial cells myelinate axons in the brain and spinal cord?

oligodendrocytes

when the neuron is at rest, ______ is mostly responsible for the movement of potassium ions out of the cell

potassium's concentration gradient

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

refractory period

A drug will prevent an action potential if it blocks the movement of ________ across the membrane

sodium

nodes or ranvier

the gaps in the myelin sheath along the axon