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

A) Is formed by cells lining tiny blood vessels in the brain
B) Is present in all parts of the brain
C) Prevents entry of all lipid-insoluble molecules into the brain
D) Both is formed by cells lining tiny blood vessels in the brain and prevents entry of all lipid-insoluble molecules into the brain are correct
E) All of the choices are correct

Correct Answer

verified

Show Answer

A) Is produced by an increased permeability to both Na⁺ and K⁺
B) Is produced by an increased permeability to Cl^- and/or K⁺
C) Is a small depolarization in a postsynaptic cell
D) Can be summed with other IPSPs to trigger an action potential in the postsynaptic cell
E) Both is produced by an increased permeability to both Na⁺ and K⁺ and can be summed with other IPSPs to trigger an action potential in the postsynaptic cell are correct

Correct Answer

verified

Show Answer

A) The concentration of K+ in A will be lower than it was at time zero
B) Diffusion of K+ from A to B will be equal to the diffusion of K+ from B to A
C) There will be a potential difference across the membrane,with side A negative relative to side B
D) The electrical and diffusion potentials for K+ will be equal in magnitude and opposite in direction
E) All of the choices are correct

Correct Answer

verified

Show Answer

A) Help to form the blood-brain barrier
B) Outnumber neurons in the central nervous system
C) Form the myelin sheath of neuronal axons
D) Both help to form the blood-brain barrier and outnumber neurons in the central nervous system are correct
E) All of the choices are correct

Correct Answer

verified

Show Answer

Correct Answer

verified

Show Answer

A) Voltage-regulated channels for Na⁺ that open in response to depolarization
B) Voltage-regulated channels for K⁺ that open in response to hyperpolarization
C) Receptor-mediated channels for Na⁺
D) Both voltage-regulated channels for Na⁺ that open in response to depolarization and voltage-regulated channels for K⁺ that open in response to hyperpolarization are correct
E) All of the choices are correct

Correct Answer

verified

Show Answer

A) Compartment A will be negatively charged relative to B
B) There is a net flux of K+ from B to A
C) There is a concentration gradient favoring Cl- diffusion from A to B and this gradient is balanced by an electric force favoring diffusion from B to A
D) Both there is a net flux of K+ from B to A and there is a concentration gradient favoring Cl- diffusion from A to B and this gradient is balanced by an electric force favoring diffusion from B to A are correct
E) All of the choices are correct

Correct Answer

verified

Show Answer

A) Graded potentials
B) Action potentials
C) Both graded potentials and action potentials
D) Neither graded potentials nor action potentials

Correct Answer

verified

Show Answer

A) There is increased permeability of the postsynaptic cell to both Na⁺ and K⁺
B) A small hyperpolarization occurs
C) An action potential in the presynaptic neuron always causes an action potential in the postsynaptic neuron
D) Both there is increased permeability of the postsynaptic cell to both Na⁺ and K⁺ and a small hyperpolarization occurs are correct
E) None of the choices are correct

Correct Answer

verified

Show Answer

A) Na⁺ channels open
B) K⁺ channels open
C) Na⁺ channels close
D) K⁺ channels close
E) Both Na⁺ channels open and K⁺ channels close are correct

Correct Answer

verified

Show Answer

A) PK⁺ becomes much greater than PNa⁺
B) PNa⁺ becomes much greater than PK⁺
C) PK⁺ is the same as PNa⁺
D) Na⁺ efflux (flow out of the cell) occurs
E) None of the choices occur

Correct Answer

verified

Show Answer

Correct Answer

verified

good,low,e...

View Answer

Show Answer

Correct Answer

verified

Show Answer

Correct Answer

verified

Show Answer

A) The rate of propagation of an action potential down an axon is independent of stimulus strength
B) Action potentials can be summed
C) A supra-threshold stimulus is required to stimulate an action potential during the absolute refractory period
D) Action potentials are conducted decrementally down the axon
E) None of the choices are true

Correct Answer

verified

Show Answer

A) Is part of the cerebellum
B) Is essential for life
C) Sends and receives information from all regions of the CNS
D) Both is part of the cerebellum and sends and receives information from all regions of the CNS are correct
E) Both is essential for life and sends and receives information from all regions of the CNS are correct

Correct Answer

verified

Show Answer

Correct Answer

verified

Show Answer

A) The permeability to Na ion is very much greater than the permeability to K ion
B) All of the K ion channels in the membrane are open
C) The voltage-gated Na ion channels are inactivated
D) The voltage-gated Na ion channels are closed
E) None of the choices are true

Correct Answer

verified

Show Answer