Flashcards in Chapter 2: Communication within the Nervous System Deck (43):
Scientists estimate that there are about __ neurons in the brain
D. 100 billion
In the nervous system, which of the following types of cells is the MOST numerous.
The nucleus of a neural cell is located in the
A neuron that transmits information between the central nervous system and a muscle is called a
A. Motor neuron
A __ neuron has an axon and several dendrites projecting away from the cell body
Which of the following statements regarding interneurons is TRUE
C. They may have no axon at all.
The neural membrane is selectively permeable to all of the following substances EXCEPT
When a neuron is at rest, __ ions are more plentiful outside of the cell
The TYPICAL resting potential of a neuron is
When the cell is at rest, K+ ions are strongly attracted across the cell membrane
B. Mostly because of the force of dillusion
All of the following are able to pass through the membrane under certain conditions EXEPT
Which of the following statements regarding the sodium-potassium pump is FALSE
C. It pumps sodium into the cell
Neurons undergo depolarization when
B. NA+ ions enter the cell
Depolarization is MOST similar to
When the neuron is at resting potential, NA+ ions are strongly attracted across the cell membrane because of
C. Both electrostatic pressure and diffusion
A neuron will fire an action potential when it is
D. Depolarized to its threshold
The outflow of K+ ions during an action potential results in
The action potentials generated by a specific neuron
A. are the same strength
Which of the following statements regarding the absolute refractory period is FALSE
A. The potassium channels are closed and cannot be opened
During the relative refractory period
D. All of the above - the neuron is hyperpolarized, a stronger stimulus may result in another action potential, potassium channels are open
The maximum speed at which a neuron can conduct an action potential seems to be about
C. 120 m/s
The __ the axon, the __ the action potential
B. Thicker, faster
In the central nervous system, myelin is formed by
in myelinated axons,
B. Action potentials occur only at the nodes of Ranvier.
Myelination results in all of the following EXCEPT
A. Increased capacitance
Which of the following was not mentioned as a function of the glial cells
D. Transmitting action potentials
Who discovered that neurons are separate cells and are NOT in contact with each other
A. Ramon y Cajal
Who demonstrated that synaptic transmission is chemical?
When an action potential reaches an axon terminal, __ ions enter the cell and trigger the release of the neurontransmitter
Fast acting receptors involved in muscle activity and sensory processing are referred to as
Under normal circumstances, the neurotransmitter molecules released by a single neuron can do all the following EXCEPT
C. Trigger an action potential
An IPSP will occur if
D. Potassium channels open and chloride channels open.
Action potentials are first produced
A. At the axon hillock
In order for spatial summation to occur.
B. Several EPSP's and/or IPSP's must arrive at the same time from different inputs.
If a neuron has a resting potential of -70 mV and a threshold of -60 mV, which of the following combinations of simultaneous postsynaptic potentials will result in an action potential
B. 50 EPSP's of .5 mV each and 20 IPSP's of 05 mV each
Acetylcholine is removed from the synapse by
C. Enzymatic deactivation
Neurotransmitters interact with receptor sites like a __
A. Key into a lock
Which of the following statements regarding nicotinic receptors is FALSE
A. They are inhibitory
Regarding the types of neurotransmitters that a neuron can release, which of the following statements is FALSE.
B. There are neurons that are incapable of releasing any neurotransmitters at all.
Which of the following is an antagonist at acetylcholine receptors?
In an artificial neural network, MOST of the processing occurs in which layer of neurons?
The ability of neurons to carry information is increased by
D. Varied time intervals of neural bursts