Bio psychology Chapter 1

The cell membrane is composed of two layers of

fat

Korsakoff's syndrome ___.

is marked by severe memory impairments.

Small, charged molecules can cross the cell membrane through ____.

protein channels

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

refractory period

what is one major cause for the resting potential of a neurons membrane?

the sodium potassium pump

What leads to Korsakoff's syndrome?

thiamine deficiency due to chronic alcoholism

why does the brain need thiamine?

to enable it to metabolize glucose

as compared to dendrites, axons usually___.

are covered with myelin

glial cells

are smaller than neurons in the human brain.

ordinarily, stimulation of a neuron takes place ___.

at the synapse

An axon has many branches, each of which swells at its tip. These are known as___.

presynaptic terminals

Local anesthetic drugs attach the sodium channels of the membrane, which ___.

prevents sodium ions from entering and stopping action potential

what mechanism prevents or slows some chemicals from entering the brain, while allowing others to enter?

a blood-brain barrier

the all-or-none law states that ____.

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

what do neurons have that other cells do not?

a plasma membrane

which type of glia removes waste material in the nervous system?

astrocytes

neurons typically have one ___, but many ___.

axon and dendrites

a drug that blocks the sodium gates of a neurons membrane will ____.

block the action potential

water, oxygen, and _____ most freely flow across a cell membrane.

carbon dioxide

if you were to accidentally touch hot stove with your hand, you would quickly pull your hand away. The information carried to the muscles in your arm to make them contract was carried by ___.

efferent neurons

The membrane of a neuron is composed of ___ with ____ embedded in them.

fat molecules and proteins.

nodes of ranvier are ___.

gaps in the myelin of axons

radial glia

guide the migration of neurons during embryonic development

the function of myelin sheath is to

increase the velocity of transmission along an axon

chemicals are released by axons ___.

into the junction between neurons

what type of neuron in the pons receives information only from other cells in the pons and sends information only to other cells in the pons?

intrinsic

Glial cells whose function most closely resembles that of the immune system are called

microglia

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

myelin sheath

the resting potential of a neuron refers to the ___.

net negative charge on the inside of the neuron

the endoplasmic reticulum is a ___.

network of thin tubes that transport newly synthesized proteins.

the two basic kinds of cells in the nervous system are

neurons and glia

santiago and ramony cajal demonstrated that

neurons are separate from one another

the structure that contains a cells chromosomes is called the

nucleus

___ in the brain and spinal cord and ___ in the periphery are specialized types of glia that build the myelin sheaths that surround neurons.

oligodendrocytes

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

open to let sodium enter the cell rapidly

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

permeability

neurons differ most strongly from other body cells in their

shape

in the normal course of an action potential, ___.

sodium remains much more concentrated outside than inside the neuron

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 receptor

which of the following is an advantage of having a resting potential?

the cell is prepared to respond quickly to a stimulus.

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

After the peak of an action potential, what prevents sodium ions from continuing to enter the cell?

the sodium gates in the membrane close

a membrane produces an action potential whenever the potential across it reaches what level?

the threshold of excitation