Neuroscience and Animal Ethics Quiz

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Questions and Answers

What is the primary function of dendrites in a neuron?

To conduct impulses toward muscles

To transport proteins to other locations

To insulate the axon

To receive excitation through synaptic receptors (correct)

Which component of the neuron is responsible for conveying impulses to other neurons or muscles?

Myelin sheath

Axon (correct)

Soma

Dendrite

What structure covers many vertebrate axons and speeds up neural conduction?

Synaptic receptors

Dendritic spines

Soma

Myelin sheath (correct)

What is the role of synapses in the nervous system?

To facilitate communication between neurons Signup and view all the answers

Which of the following statements about sensory neurons is true?

They are specialized to be sensitive to specific types of stimuli. Signup and view all the answers

What structure serves as the control center of the neuron, containing important organelles?

Soma Signup and view all the answers

What are dendritic spines primarily used for in neurons?

Enhancing the surface area for synaptic connections Signup and view all the answers

How does the structure of a motor neuron differ from that of a sensory neuron?

Motor neurons have longer axons than sensory neurons Signup and view all the answers

What is the primary function of presynaptic terminals?

To release chemicals to transmit signals to another cell. Signup and view all the answers

Which type of neuron carries information away from a structure?

Efferent neuron Signup and view all the answers

What role do radial glia play during embryonic development?

They guide the migration of neurons and their axons and dendrites. Signup and view all the answers

What structure is formed when a neuron's dendrites and axon are contained within a single entity?

Interneuron Signup and view all the answers

Which type of glia are star-shaped and wrap around the synapses of related axons?

Astrocytes Signup and view all the answers

Who is regarded as a pioneer of modern neuroscience?

Charles Sherrington Signup and view all the answers

What term describes the pathway that involves the synaptic interaction between an afferent neuron and an efferent neuron?

Reflex arc Signup and view all the answers

What does the term 'glia' derive from, and what does it reflect about their early conceptualization?

Greek meaning 'glue', reflecting their supportive role for neurons. Signup and view all the answers

What primarily drives sodium ions into the cell during an action potential?

Concentration gradient and electrical gradient Signup and view all the answers

What happens to sodium channels at the peak of the action potential?

They close immediately Signup and view all the answers

What effect does the opening of potassium channels have during an action potential?

Hyperpolarization of the membrane Signup and view all the answers

How does the amplitude of an action potential relate to the intensity of the stimulus?

It remains constant regardless of stimulus intensity Signup and view all the answers

What role do voltage-gated channels play in action potentials?

Their permeability depends on the voltage difference across the membrane Signup and view all the answers

What occurs immediately after the sodium channels close during an action potential?

Potassium ions start to flow out of the axon Signup and view all the answers

What is the primary type of cell that differentiates into neurons during development?

Radial glia Signup and view all the answers

What triggers the initial opening of sodium and potassium channels in the axon membrane?

Reaching the threshold of excitation Signup and view all the answers

Which hypothesis suggests that the interaction between axons and astrocytes modifies synaptic activity?

Tripartite synapse Signup and view all the answers

What type of cells build myelin sheaths in the central nervous system?

Oligodendrocytes Signup and view all the answers

During hyperpolarization, what is the state of the membrane potential compared to its resting level?

It is more negative than resting level Signup and view all the answers

What do oligodendrocytes provide to axons for proper functioning?

Nutrients Signup and view all the answers

What is one major function of the blood-brain barrier?

To block viruses and harmful chemicals from entering the brain Signup and view all the answers

Which virus is mentioned as being able to evade the blood-brain barrier?

Rabies Signup and view all the answers

What substance do vertebrate neurons primarily depend on for nourishment?

Glucose Signup and view all the answers

What happens to cells outside the brain in terms of their connectivity, compared to cells in the brain?

They are more loosely connected with larger gaps. Signup and view all the answers

What does the sodium-potassium pump primarily do?

Transports three sodium ions out and two potassium ions in Signup and view all the answers

What change in membrane potential does hyperpolarization refer to?

An increase in negative charge inside the neuron Signup and view all the answers

What occurs when a depolarizing current is applied to a neuron?

The potential may rise but will eventually return to resting level Signup and view all the answers

What is the significance of reaching the threshold of excitation?

An action potential will be generated Signup and view all the answers

What is the typical resting membrane potential of a neuron?

-70 mV Signup and view all the answers

What happens to the membrane potential during action potential generation?

It experiences a massive depolarization Signup and view all the answers

What role does the electrical chemical gradient play in a resting neuron's membrane potential?

It helps establish a negative internal charge Signup and view all the answers

What occurs when a stimulation is applied beyond the action potential threshold?

A significant depolarization occurs Signup and view all the answers

Study Notes

Endoplasmic Reticulum

A network of thin tubes involved in the transport of newly synthesized proteins to various locations within the cell.

Structure of Neuron

Neurons consist of a soma (cell body), dendrites, axons, and presynaptic terminals.
Motor neurons receive excitation through dendrites and transmit impulses along their axons to muscles.
Sensory neurons are specialized to respond to specific stimuli like light, sound, or touch.
The axon is a thin, constant-diameter fiber that conveys impulses toward other neurons, organs, or muscles, with lengths exceeding one meter in some cases.

Dendrites and Synapse

Dendrites branch out and narrow at their ends, lined with synaptic receptors for communication.
Dendritic spines increase surface area for synapses.
The soma contains nucleus, ribosomes, and mitochondria, performing most metabolic work.

Myelin Sheath and Nodes of Ranvier

Many vertebrate axons are insulated by a myelin sheath, which aids in efficient impulse conduction.
There are interruptions in the sheath known as nodes of Ranvier.

Reflexes and Neuron Classification

Reflexes are automatic responses to stimuli involving a reflex arc.
Afferent axons carry sensory information into a structure, while efferent axons transmit information away.
Interneurons have their dendrites and axon entirely within a single structure.

Glia

Glia, or neuroglia, support neurons and perform various functions; their name means "glue."
Radial glia guide neuron migration during development.
Astrocytes wrap around synapses, influencing neuron interactions.

Tripartite Synapse

An axon's tip can stimulate an astrocyte to release its own chemicals, enhancing neuronal communication.

Oligodendrocytes and Schwann Cells

Oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system form and maintain myelin sheaths.

Blood-Brain Barrier

Protects the brain by tightly joining cells to block viruses and harmful substances while allowing nutrients like glucose to pass.
Certain viruses, like rabies, can cross this barrier, leading to serious health issues.

Neuronal Nourishment

Vertebrate neurons rely primarily on glucose for energy.
The sodium–potassium pump actively transports sodium out and potassium into the neuron, creating an electrical gradient.

Resting Potential

Neurons have a resting potential around -70mV, established by the sodium–potassium pump's activity.

Action Potential

Action potentials occur when depolarization reaches a threshold, leading to a rapid influx of sodium ions.
Sodium channels open, allowing sodium ions to rush in, which then opens voltage-gated channels further along the axon.

Principles of Action Potential

Sodium ions are predominantly outside the neuron at rest.
When depolarized, sodium channels open and sodium enters, while potassium channels eventually open, allowing potassium to exit.
This results in transient hyperpolarization as potassium ions leave after the sodium channels close.

Summary of Action Potential Dynamics

An action potential involves a quick sequence of depolarization followed by repolarization, defined by voltage-gated channels that respond to changes in membrane potential.
The amplitude and velocity of action potentials are consistent regardless of stimulus intensity after reaching the threshold.

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Description

This quiz explores crucial concepts in neuroscience, including the structure of neurons and the role of the endoplasmic reticulum in protein transport. Additionally, it covers ethical considerations surrounding the study of animals in research. Test your knowledge on these important topics!