Nerve impulses and synapses

Question 1

What does the resting membrane potential primarily depend on?
A) High external concentration of potassium
B) Equal sodium and potassium concentrations across the membrane
C) High internal concentration of potassium
D) Low internal concentration of sodium

Answer 1

c

Question 2

What is the main function of the myelin sheath?
A) To increase the metabolic activity of the neuron
B) To decrease the speed of the action potential
C) To insulate the axon and increase the speed of transmission
D) To produce neurotransmitters

Answer 2

c

Question 3

Which ion channel opens in response to a change in membrane potential?
A) Chemically gated channels
B) Mechanically gated channels
C) Voltage-gated channels
D) Leakage channels

Answer 3

c

Question 4

What is the typical value of the resting membrane potential of a neuron?
A) +30 mV
B) 0 mV
C) -70 mV
D) +70 mV

Answer 4

c

Question 5

What occurs during depolarization of a neuron?
A) The inside of the neuron becomes more negative
B) The neuron reaches its threshold potential
C) The inside of the neuron becomes less negative
D) Potassium ions rush into the neuron

Answer 5

c

Question 6

Which type of potential does not diminish in strength as it travels away from its source?
A) Graded potential
B) Resting potential
C) Action potential
D) Hyperpolarization

Answer 6

c

Question 7

Where are neurotransmitters stored within the neuron?
A) In the myelin sheath
B) In the nucleus
C) In synaptic vesicles
D) In the axonal membrane

Answer 7

c

Question 8

Which of the following best describes an action potential?
A) It is graded based on the strength of the stimulus
B) It is initiated when the membrane potential reaches about -55 mV
C) It occurs when potassium ions enter the neuron
D) It spreads by decrement

Answer 8

b

Question 9

Which neurotransmitter is primarily involved in the excitation of muscles?
A) Dopamine
B) Serotonin
C) GABA
D) Acetylcholine

Answer 9

d

Question 10

Synaptic transmission is the process by which:
A) Neurons regenerate after damage
B) Neurons communicate with each other through synapses
C) Neurons prevent action potentials
D) Neurons release hormones into the blood

Answer 10

b

Question 11

What is the role of calcium ions in synaptic transmission?
A) They trigger the hyperpolarization of the postsynaptic membrane
B) They promote the diffusion of neurotransmitters across the synaptic cleft
C) They initiate the repolarization phase of the action potential
D) They trigger the release of neurotransmitters from the presynaptic neuron

Answer 11

d

Question 12

Which statement is true regarding graded potentials?
A) They can only cause depolarization
B) They increase in strength as they travel through the neuron
C) They can summate to trigger an action potential
D) They occur only in the axon hillock

Answer 12

c

Question 13

What type of synapse involves direct electrical connections via gap junctions?
A) Chemical synapse
B) Electrical synapse
C) Synaptic synapse
D) Mechanical synapse

Answer 13

b

Question 14

What happens during hyperpolarization of a neuron?
A) The membrane potential becomes more positive than the resting potential
B) The membrane potential becomes more negative than the resting potential
C) Sodium ions flood into the cell
D) The neuron becomes less responsive to stimuli

Answer 14

b

Question 15

Which of the following is not a function of neurotransmitters?
A) Modifying the permeability of the postsynaptic membrane
B) Carrying signals to the brain
C) Binding to receptors on the postsynaptic membrane
D) Influencing the psychological state

Answer 15

b

Question 16

Voltage-gated channels are directly triggered by:
A) The binding of neurotransmitters
B) Mechanical pressure
C) Changes in membrane potential
D) The presence of specific ions

Answer 16

c

Question 17

What is the primary purpose of the sodium-potassium pump in neuronal function?
A) To create the resting membrane potential
B) To generate neurotransmitters
C) To propagate graded potentials
D) To detoxify the neuron

Answer 17

a

Question 18

Which of the following is a characteristic feature of chemical synapses but not of electrical synapses?
A) Rapid signal transmission
B) The presence of a synaptic cleft
C) The ability to send bidirectional signals
D) The use of neurotransmitters

Answer 18

b

Question 19

What effect does the neurotransmitter GABA have on the postsynaptic neuron?
A) It causes depolarization
B) It has no effect on the membrane potential
C) It causes hyperpolarization
D) It increases calcium ion permeability

Answer 19

c

Question 20

The absolute refractory period ensures that:
A) An action potential only travels in one direction
B) Action potentials are all of the same magnitude
C) Neurons can fire action potentials in rapid succession
D) The neuron cannot fire another action potential

Answer 20

a