Neuroscience Quiz: Neuron Structure and Function
33 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary role of dendrites in a neuron?

  • To receive impulses from other neurons (correct)
  • To form myelin sheaths around the axon
  • To insulate the axon and prevent loss of impulses
  • To conduct electrical impulses away from the cell body

Which type of neuron carries impulses from receptors to the CNS?

  • Sensory neurons (correct)
  • Motor neurons
  • Glial cells
  • Relay neurons

How does the sodium-potassium pump contribute to the resting potential of a neuron?

  • By creating an action potential in the axon
  • By allowing potassium ions to flow freely across the membrane
  • By increasing sodium concentration outside the neuron (correct)
  • By maintaining a higher concentration of potassium inside the neuron (correct)

What defines the resting potential in a neuron?

<p>The state of the neuron when it is not transmitting an impulse (C)</p> Signup and view all the answers

What is one characteristic of motor neurons?

<p>They have a large cell body that lies within the spinal cord or brain. (C)</p> Signup and view all the answers

What defines a nerve impulse?

<p>A rapid change in membrane potential that propagates along the nerve fiber (B)</p> Signup and view all the answers

What is the function of Schwann cells in relation to neurons?

<p>To increase the efficiency of impulse transmission along the axon (D)</p> Signup and view all the answers

What occurs during the action potential in a neuron?

<p>There is a rapid depolarization followed by repolarization of the membrane (C)</p> Signup and view all the answers

What initiates the depolarization phase of an action potential?

<p>Opening of voltage-gated Na+ channels (D)</p> Signup and view all the answers

During repolarization, what is the primary ion that moves out of the axon?

<p>Potassium (K+) (D)</p> Signup and view all the answers

What is the threshold potential that must be reached to trigger an action potential?

<p>$-50mV$ (B)</p> Signup and view all the answers

What causes the depolarization phase of a nerve impulse?

<p>Sodium channels in the membrane open, allowing Na+ ions to diffuse in. (A)</p> Signup and view all the answers

What role do nodes of Ranvier play in myelinated neurons?

<p>They are sites of sodium and potassium ion channel clustering (D)</p> Signup and view all the answers

How do neonicotinoids affect synaptic transmission?

<p>They block acetylcholine receptors irreversibly (C)</p> Signup and view all the answers

What is the primary role of acetylcholinesterase in synaptic transmission?

<p>To break down acetylcholine in the synaptic gap. (C)</p> Signup and view all the answers

Which statement describes saltatory conduction?

<p>It is characterized by action potentials jumping between nodes of Ranvier. (C)</p> Signup and view all the answers

Which neurotransmitter typically acts to inhibit postsynaptic potentials?

<p>GABA (A)</p> Signup and view all the answers

During repolarization, which ion primarily exits the neuron to restore the resting potential?

<p>Potassium ions. (A)</p> Signup and view all the answers

What does summation refer to in neural transmission?

<p>The accumulation of neurotransmitter effects needed to reach threshold potential (C)</p> Signup and view all the answers

Which of the following best describes saltatory conduction?

<p>Action potentials jumping from node to node (B)</p> Signup and view all the answers

What primarily accounts for the unequal pumping of Na+ and K+ ions during resting potential?

<p>The structure of the sodium-potassium pump. (A)</p> Signup and view all the answers

What is the effect of hyperpolarization in a postsynaptic neuron?

<p>Decreased likelihood of firing an action potential (A)</p> Signup and view all the answers

Which ion acts as a chemical signal that triggers the release of neurotransmitters via exocytosis?

<p>Calcium. (C)</p> Signup and view all the answers

What occurs to sodium (Na+) channels during depolarization?

<p>They open and remain open (B)</p> Signup and view all the answers

What effect does myelination have on the speed of nerve impulse conduction?

<p>It increases conduction speed. (B)</p> Signup and view all the answers

Which of the following statements about consciousness is correct?

<p>Consciousness is an emergent property of interacting neurons (C)</p> Signup and view all the answers

What is the function of the sodium-potassium pump after an action potential?

<p>To maintain the resting potential through continuous ion exchange. (A)</p> Signup and view all the answers

Which type of receptor proteins can activate nerve endings in response to environmental stimuli?

<p>Ion channels for positively charged ions (D)</p> Signup and view all the answers

What occurs immediately after depolarization in the action potential sequence?

<p>Repolarization due to efflux of potassium ions. (C)</p> Signup and view all the answers

Which of the following best describes the effect of cocaine on synaptic transmission?

<p>Increases dopamine concentration in the synaptic cleft (C)</p> Signup and view all the answers

How do local currents contribute to the propagation of action potentials along an axon?

<p>They cause regions of the axon to reach threshold potential sequentially. (D)</p> Signup and view all the answers

What characterizes an excitatory postsynaptic potential (EPSP)?

<p>It results from neurotransmitter binding and Na+ influx. (B)</p> Signup and view all the answers

Which of the following accurately describes a synapse?

<p>A junction that allows signal transmission in one direction. (B)</p> Signup and view all the answers

Flashcards

Neuron function

Neurons are cells in the nervous system that transmit electrical signals.

Neuron parts

Neurons consist of a cell body, axon, and dendrites.

Sensory neuron

Carries impulses from receptors to the central nervous system (CNS).

Motor neuron

Carries impulses from CNS to effectors (muscles or glands).

Signup and view all the flashcards

Resting potential

The electrical potential difference across the neuron membrane when it's not transmitting a signal.

Signup and view all the flashcards

Membrane potential

The difference in electrical charge across a cell membrane.

Signup and view all the flashcards

Nerve impulse

The propagation of an action potential along a nerve fiber.

Signup and view all the flashcards

Action potential

A rapid change in membrane potential that allows a signal to travel along a nerve fiber.

Signup and view all the flashcards

Depolarization

The process where the inside of a neuron becomes more positive relative to the outside due to the influx of sodium ions through open channels.

Signup and view all the flashcards

Repolarization

The process where the inside of a neuron returns to its negative resting potential after depolarization, caused by the outflow of potassium ions.

Signup and view all the flashcards

Sodium-Potassium Pump

A protein pump that actively transports sodium ions out of the neuron and potassium ions into the neuron, maintaining the concentration gradients necessary for action potentials.

Signup and view all the flashcards

Axon Diameter

The thickness of the axon, which influences the speed of nerve impulse conduction.

Signup and view all the flashcards

Myelinated Nerve Fiber

A nerve fiber coated in myelin, a fatty substance that acts as an insulator, speeding up nerve impulse conduction.

Signup and view all the flashcards

Saltatory Conduction

The jumping of nerve impulses from one node of Ranvier (gap in the myelin sheath) to the next, increasing conduction speed.

Signup and view all the flashcards

Synapse

The junction between two neurons or between a neuron and an effector cell where information is transmitted.

Signup and view all the flashcards

Synaptic Cleft

The narrow gap between the presynaptic and postsynaptic membranes at a synapse.

Signup and view all the flashcards

Effector

A muscle or gland that responds to a nerve impulse.

Signup and view all the flashcards

Neurotransmitter

A chemical messenger released from the presynaptic neuron at a synapse, which diffuses across the synaptic cleft and binds to receptors on the postsynaptic membrane.

Signup and view all the flashcards

Excitatory Neurotransmitter

A neurotransmitter that increases the likelihood of an action potential in the postsynaptic neuron.

Signup and view all the flashcards

Inhibitory Neurotransmitter

A neurotransmitter that decreases the likelihood of an action potential in the postsynaptic neuron.

Signup and view all the flashcards

Threshold Potential

The minimum level of depolarization required to trigger an action potential in a neuron.

Signup and view all the flashcards

What is the threshold potential?

The minimum membrane potential that must be reached for an action potential to be triggered.

Signup and view all the flashcards

What do voltage-gated sodium channels do during depolarization?

Voltage-gated sodium channels open when the membrane potential reaches the threshold potential, allowing sodium ions to flow into the neuron, further increasing the membrane potential.

Signup and view all the flashcards

What do voltage-gated potassium channels do during repolarization?

Voltage-gated potassium channels open as the membrane potential becomes more positive during depolarization, allowing potassium ions to flow out of the neuron, reducing the membrane potential.

Signup and view all the flashcards

What is an oscilloscope trace?

A visual representation of the electrical activity of a neuron over time, showing the changes in its membrane potential.

Signup and view all the flashcards

What is the refractory period?

A brief period after an action potential where the neuron is less likely to fire another action potential.

Signup and view all the flashcards

What is the structure of a myelinated nerve fiber?

A myelinated nerve fiber has an axon wrapped in myelin, a fatty substance that acts as an insulator, with gaps called nodes of Ranvier.

Signup and view all the flashcards

How does myelination allow for faster nerve impulses?

Myelin prevents the flow of ions across the axon membrane except at the nodes of Ranvier, forcing the action potential to 'jump' from node to node, speeding up the transmission.

Signup and view all the flashcards

Exogenous chemicals

Chemicals that come from outside the body, such as drugs or pesticides.

Signup and view all the flashcards

What is the effect of neonicotinoids on synaptic transmission?

Neonicotinoids bind to acetylcholine receptors, causing sodium channels to remain open, leading to overstimulation and paralysis.

Signup and view all the flashcards

What is the effect of cocaine on synaptic transmission?

Cocaine blocks dopamine reuptake transporters, causing dopamine to build up in the synapse, leading to increased excitation.

Signup and view all the flashcards

What is the difference between excitatory and inhibitory neurotransmitters?

Excitatory neurotransmitters increase the likelihood of a postsynaptic neuron firing by causing depolarization, while inhibitory neurotransmitters decrease the likelihood of firing by causing hyperpolarization.

Signup and view all the flashcards

What does GABA do?

GABA is an inhibitory neurotransmitter that binds to receptors and opens chloride channels, causing hyperpolarization of the postsynaptic neuron.

Signup and view all the flashcards

What is summation?

The combined effect of multiple excitatory or inhibitory neurotransmitters on a postsynaptic neuron.

Signup and view all the flashcards

More Like This

Neuron Anatomy and Classification Quiz
3 questions

Neuron Anatomy and Classification Quiz

ImmenseParadise avatar
ImmenseParadise
Neuron Structure and Function
9 questions

Neuron Structure and Function

PatriAmbiguity399 avatar
PatriAmbiguity399
5 Major Parts of a Neuron Flashcards
6 questions

5 Major Parts of a Neuron Flashcards

SharperEducation9982 avatar
SharperEducation9982
PSYU2236 W2 | The Neuron
34 questions

PSYU2236 W2 | The Neuron

legallykensington avatar
legallykensington
Use Quizgecko on...
Browser
Open
Browser
Browser