Question 1

Which of the following best explains why large-diameter axons conduct action potentials faster than small-diameter axons?

Accepted Answer

Large-diameter axons have less resistance to ion flow, allowing action potentials to propagate more quickly.

Question 2

During an action potential, what is the primary cause of depolarization of the neuron's membrane?

Accepted Answer

Opening of voltage-gated Na+ channels, allowing Na+ to enter the cell.

Question 3

Which of the following is a key difference between chemical and electrical synapses?

Accepted Answer

Chemical synapses transmit signals via neurotransmitters, while electrical synapses transmit signals via direct ion flow through gap junctions.

Question 4

What would happen to the resting membrane potential if more voltage-gated K+ channels were open at rest?

Accepted Answer

The membrane would become hyperpolarized.

Question 5

Which of the following best describes the 'all-or-none' property of action potentials?

Accepted Answer

Action potentials only occur if the membrane depolarizes above a threshold value.

Question 6

Saltatory conduction in myelinated axons is faster than continuous conduction because:

Accepted Answer

Action potentials jump from one node of Ranvier to the next, skipping myelinated regions.

Question 7

Which sequence correctly describes the events at a chemical synapse?

Accepted Answer

Action potential arrives → Voltage-gated Ca2+ channels open → Synaptic vesicles fuse with membrane → Neurotransmitter released

Question 8

Which type of sensory receptor is responsible for detecting changes in temperature?

Accepted Answer

Thermoreceptors

Question 9

A person is unable to see color but can still see in dim light. Which photoreceptor cells are likely nonfunctional?

Accepted Answer

Cones

Question 10

Which of the following best explains why there is a 'blind spot' in the human eye?

Accepted Answer

There are no photoreceptors where the optic nerve exits the eye.

Question 11

If a neuron’s membrane potential is at $$-70\ \mathrm{mV}$$ and the threshold for firing an action potential is $$-55\ \mathrm{mV}$$, what must occur for the neuron to fire?

Accepted Answer

The membrane must depolarize by at least $$15\ \mathrm{mV}.$$

Question 12

Which of the following is a function of the Na+/K+ pump in neurons?

Accepted Answer

It restores the resting membrane potential after an action potential.

Question 13

Which of the following scenarios best illustrates the integration of sensory input and motor output?

Accepted Answer

A person hears a loud noise and immediately turns their head toward the sound.

Question 14

Which of the following is true about the propagation of an action potential along an axon?

Accepted Answer

It is self-propagating and maintains its intensity as it moves in one direction.

Question 15

Which of the following best describes the role of mechanoreceptors in the human body?

Accepted Answer

They detect physical deformation such as pressure, stretch, and motion.

Question 16

Which of the following is a direct result of neurotransmitter binding to receptors on the postsynaptic membrane?

Accepted Answer

Opening or closing of ion channels, leading to a postsynaptic potential.

Question 17

Which of the following is an example of a real-world application of understanding action potentials?

Accepted Answer

Treating multiple sclerosis, a disease where myelin sheaths are damaged, slowing action potential conduction.

Question 18

Which of the following best explains why spicy foods taste 'hot'?

Accepted Answer

They activate the same thermoreceptors that respond to high temperatures.

Question 19

Which of the following is the correct order of events for hearing a sound?

Accepted Answer

Sound waves vibrate the tympanic membrane → Vibrations transmitted by middle ear bones → Pressure waves in cochlea → Bending of hair cells → Signal sent to auditory nerve

Animal Responses to the Environment: Neurons, Synapses, and Sensory Systems

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