Bio Psy Ch. 1
The cell membrane is composed of two layers of
fat
Nodes of Ranvier are ____.
gaps in the myelin of axons
The insulating material that covers many vertebrate axons is called the ____.
myelin sheath
What mechanism prevents or slows some chemicals from entering the brain, while allowing others to enter?
a blood-brain barrier
As a general rule, axons convey information ____.
away from their own cell body
The concentration gradient refers to the ____.
difference in distribution for various ions between the inside and outside of the membrane
In what direction does a local neuron transmit information?
equally well in any direction
What is the main source of nutrition for vertebrate neurons?
glucose
Under which conditions would the sodium-potassium pump likely be far less effective in creating a concentration gradient?
if selective permeability of the membrane did not exist
Local anesthetic drugs attach to the sodium channels of the membrane, which ____.
prevents sodium ions from entering and stopping action potential
The surface of a dendrite is lined with specialized junctions through which the dendrite receives information from other neurons. What are these junctions called?
synaptic receptors
What leads to Korsakoff's syndrome?
thiamine deficiency due to chronic alcoholism
Increasing the electrical gradient for potassium will reduce the tendency for potassium ions to exit the neuron.
True
Water, oxygen, and ____ most freely flow across a cell membrane.
carbon dioxide
Radial glia ____.
guide the migration of neurons during embryonic development
An axon has many branches, each of which swells at its tip. These are known as ____.
presynaptic terminals
A presynaptic terminal is also known as ____.
an end bulb
At the resting potential, the potassium channels are completely closed and the sodium channels are almost closed.
False
The membrane of a neuron is composed of ____ with ____ embedded in them.
fat molecules; proteins
The resting potential is mainly the result of ____.
negatively charged proteins inside the cell
Ordinarily, stimulation of a neuron takes place ____.
at the synapse
The neuron will produce an action potential only if the depolarization exceeds the ____.
the threshold of excitation
Neurons typically have one ____, but many ____.
axon; dendrites
What type of glial cells myelinate axons in the brain and spinal cord?
oligodendrocytes
The concentration gradient for potassium tends to ____.
push potassium out of the cell
Protein channels allow ____ molecules to cross the cell membrane.
small charged