Question 1

An increase in the extracellular concentration of K+ above normal would result in

Accepted Answer

A) Depolarization of resting nerve cells 
B) Hyperpolarization of resting nerve cells 
C) No change in the resting membrane potential

Question 2

Graded potentials

Accepted Answer

A) Include receptor potentials and postsynaptic potentials 
B) Are conducted decrementally 
C) Include depolarizing and hyperpolarizing potentials 
D) Can be summed 
E) Are described by all of the choices

Question 3

Which of the following statements about the phases of an action potential are correct?

Accepted Answer

A) During the hyperpolarizing phase, the permeability of the membrane to sodium ion is greater than its permeability at rest 
B) During the hyperpolarizing phase, the permeability of the membrane to potassium ion is greater than its permeability at rest 
C) During the repolarizing phases, the permeability of the membrane to potassium ion is greater than its permeability at rest 
D) Both during the hyperpolarizing phase, the permeability of the membrane to sodium ion is greater than its permeability at rest and during the repolarizing phases, the permeability of the membrane to potassium ion is greater than its permeability at rest are correct 
E) Both during the hyperpolarizing phase, the permeability of the membrane to potassium ion is greater than its permeability at rest and during the repolarizing phases, the permeability of the membrane to potassium ion is greater than its permeability at rest are correct

Question 4

The binding of nicotine with nicotinic acetylcholine receptors can trigger each of the following effects,except

Accepted Answer

A) A mild form of skeletal muscle paralysis to create a more relaxed state 
B) Mediation of signal transmission at neuromuscular junctions 
C) Generation of excitatory signals within autonomic ganglia 
D) The release of norepinephrine, dopamine and epinephrine 
E) Facilitation of the release of multiple neurotransmitters within the brain, including the "reward pathway" involving dopamine

Question 5

The cerebrum consists only of gray matter.

Accepted Answer

A) True 
 B)False

Question 6

The most numerous cells in the CNS are interneurons.

Accepted Answer

A) True 
 B)False

Question 7

Which of the following statements regarding action potentials generated in a membrane is not true?

Accepted Answer

A) Action potentials travel decrementally down the membrane 
B) An action potential generates a new action potential in an adjacent area of membrane 
C) An action potential generates a local current that depolarizes adjacent membrane to threshold potential 
D) The first action potential generated is the same size as the action potential ultimately generated at the end of the membrane 
E) An action potential generated by a threshold stimulus is the same size as one generated by a supra-threshold stimulus

Question 8

The refractory period of an excitable membrane refers to the period of time during which no stimulus,however strong,will elicit a second action potential in the membrane.

Accepted Answer

A) True 
 B)False

Question 9

Because all parts of a neuronal cell body have the same threshold,no one synapse on the cell is more important than any other.

Accepted Answer

A) True 
 B)False

Question 10

During a hyperpolarizing graded potential,positively charged ions flow away from the site of the initial hyperpolarization on the outside of membrane and toward this site on the inside.

Accepted Answer

A) True 
 B)False

Question 11

Serotonin

Accepted Answer

A) Is a neuromodulator 
B) Facilitates incoming sensory stimuli in the CNS 
C) Activity in the brain is highest during sleep 
D) Both is a neuromodulator and facilitates incoming sensory stimuli in the CNS are correct 
E) Both is a neuromodulator and activity in the brain is highest during sleep are correct

Question 12

A myelinated axon is shielded from direct contact with the extracellular fluid all along its length.

Accepted Answer

A) True 
 B)False

Question 13

Postganglionic neuron cell bodies of the autonomic nervous system have which category of neurotransmitter receptor?

Accepted Answer

A) Adrenergic receptor 
B) Serotonin receptors 
C) M-AchR receptors 
D) N-AchR receptors 
E) Dopamine receptors

Question 14

Because so many Na ions move into a cell during an action potential and so many K ions move out,no further action potentials can be generated in a given membrane until the Na,K-ATPase pumps can restore the concentration gradient.

Accepted Answer

A) True 
 B)False

Question 15

A postsynaptic neuron has three presynaptic inputs - from neurons X,Y and Z.When X and Y are stimulated simultaneously and repeatedly,the postsynaptic neuron reaches threshold and undergoes an action potential.When X and Z are stimulated simultaneously,however,there is no change in the membrane potential of the postsynaptic neuron.The simultaneous stimulation of X and Y is an example of

Accepted Answer

A) Temporal summation 
B) Presynaptic inhibition 
C) Spatial summation 
D) Neuronal divergence 
E) None of the choices are correct

Question 16

The Na+ and K+ channels that open during an action potential are voltage regulated,both responding to hyperpolarization of the membrane.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following is/are functions of the human nervous system?

Accepted Answer

A) Receiving, storing and processing information on the internal and external environments 
B) Bringing about changes in physiology and/or behavior to ensure optimal functions of homeostatic mechanisms 
C) Secretion of hormones 
D) Coordination of movement 
E) All of the choices are correct

Question 18

The Na,K-ATPase in a nerve cell

Accepted Answer

A) Maintains an electrical gradient such that the inside is negative with respect to the outside 
B) Maintains a concentration gradient for K+ such that diffusion forces favor movement of K+ into the cell 
C) Maintains an electrical gradient at the equilibrium potential of K+ 
D) Transports an equal number of sodium and potassium ions 
E) Both maintains an electrical gradient such that the inside is negative with respect to the outside and transports an equal number of sodium and potassium ions are correct

Question 19

Responses made possible by motor signals transmitted by the parasympathetic nervous system tend to be displayed throughout the body simultaneously because there is much divergence of nerve pathways and close anatomical association between presynaptic neurons and their ganglia as well as accessory activity with the adrenal glands.

Accepted Answer

A) True 
 B)False

Question 20

The basal ganglia are important subcortical nuclei in the cerebrum.

Accepted Answer

A) True 
 B)False

Exam 6: Neuronal Signaling and the Structure of the Nervous System

An increase in the extracellular concentration of K⁺ above normal would result in

Graded potentials

Which of the following statements about the phases of an action potential are correct?

The binding of nicotine with nicotinic acetylcholine receptors can trigger each of the following effects,except

The cerebrum consists only of gray matter.

The most numerous cells in the CNS are interneurons.

Which of the following statements regarding action potentials generated in a membrane is not true?

The refractory period of an excitable membrane refers to the period of time during which no stimulus,however strong,will elicit a second action potential in the membrane.

Because all parts of a neuronal cell body have the same threshold,no one synapse on the cell is more important than any other.

During a hyperpolarizing graded potential,positively charged ions flow away from the site of the initial hyperpolarization on the outside of membrane and toward this site on the inside.

Serotonin

A myelinated axon is shielded from direct contact with the extracellular fluid all along its length.

Postganglionic neuron cell bodies of the autonomic nervous system have which category of neurotransmitter receptor?

Because so many Na ions move into a cell during an action potential and so many K ions move out,no further action potentials can be generated in a given membrane until the Na,K-ATPase pumps can restore the concentration gradient.

The Na⁺ and K⁺ channels that open during an action potential are voltage regulated,both responding to hyperpolarization of the membrane.

Which of the following is/are functions of the human nervous system?

The Na,K-ATPase in a nerve cell

The basal ganglia are important subcortical nuclei in the cerebrum.