Nervous System Quiz: Myelin and Glial Cells

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Questions and Answers

What is the primary function of myelin insulation?

To regulate the production of neurotransmitters.

To provide structural support to neurons.

To increase the speed of electrical signaling along axons. (correct)

To prevent the leakage of neurotransmitters from synaptic clefts.

Which of the following accurately describes the difference between Schwann cells and oligodendrocytes?

Oligodendrocytes are responsible for synaptic transmission, while Schwann cells are not.

Schwann cells are found in the CNS, while oligodendrocytes are found in the PNS.

Schwann cells produce myelin, while oligodendrocytes produce a different type of insulating material.

Oligodendrocytes can insulate multiple axon segments, while Schwann cells typically insulate only one segment. (correct)

What is the primary cause of demyelinating diseases, like Multiple Sclerosis?

An autoimmune reaction where the body attacks myelin. (correct)

A genetic defect that prevents the formation of myelin.

An overproduction of myelin by glial cells.

A buildup of neurotransmitters at the synapse.

What is the name of the demyelinating disease that primarily affects the peripheral nervous system?

Guillain-Barré Syndrome (D) Signup and view all the answers

What is the significance of the scarring that occurs in Multiple Sclerosis?

Scarring signals the body's attempt to repair the damaged myelin, but the scar tissue is not as efficient as the original myelin. (A) Signup and view all the answers

Which of the following symptoms is NOT commonly associated with Multiple Sclerosis?

Loss of sensation in the limbs. (C) Signup and view all the answers

What is the primary function of the nervous system in relation to the body?

To regulate and coordinate bodily functions. (D) Signup and view all the answers

Which of the following is NOT a key function of nervous tissue?

Secretion: Producing hormones that regulate metabolism. (B) Signup and view all the answers

What is the primary function of glial cells in the nervous system?

To support and protect neurons (B) Signup and view all the answers

What is the name of the glial cell type in the CNS responsible for producing cerebrospinal fluid (CSF)?

Ependymal cell (D) Signup and view all the answers

Which of the following is NOT a function of astrocytes?

Myelinating axons (B) Signup and view all the answers

Which of the following glial cells is responsible for immune surveillance and phagocytosis in the CNS?

Microglia (C) Signup and view all the answers

What is the main difference between Schwann cells and oligodendrocytes?

Schwann cells myelinate only one axon, while oligodendrocytes myelinate multiple axons. (C) Signup and view all the answers

Which of the following is a characteristic of neurons that distinguishes them from glial cells?

Neurons are capable of transmitting electrical impulses, while glial cells are not. (A) Signup and view all the answers

Why is the term "neuroglia" considered an apt name for these cells?

Because they provide structural and functional support for neurons, like a glue holding them together. (C) Signup and view all the answers

Which type of glial cell is primarily responsible for forming the myelin sheath around axons in the peripheral nervous system (PNS)?

Schwann cells (C) Signup and view all the answers

What occurs to the membrane potential during repolarization?

It decreases below resting potential, entering hyperpolarization. (A), It returns to the resting potential of -70 mV. (D) Signup and view all the answers

What initiates the change in membrane potential at +30 mV?

Sodium ions entering the cell. (C) Signup and view all the answers

How is the membrane potential described in analogy to a common object?

It is compared to a battery. (A) Signup and view all the answers

What determines the equilibrium of potassium ions?

The concentration gradient and the membrane voltage. (A) Signup and view all the answers

What characterizes the phase of hyperpolarization?

The membrane continues to lose positive charge. (D) Signup and view all the answers

What magnitude change does the action potential represent?

A change of 100 mV. (C) Signup and view all the answers

What is primarily responsible for the delay in potassium channel closure during repolarization?

The inherent property of potassium channels. (B) Signup and view all the answers

Which of the following best describes the action potential sequence?

Depolarization, repolarization, hyperpolarization. (B) Signup and view all the answers

What is the primary function of oligodendrocytes in the central nervous system?

To insulate axons with myelin. (D) Signup and view all the answers

Which glial cell type is considered a CNS-resident macrophage?

Microglia (B) Signup and view all the answers

What role do ependymal cells play in relation to the blood-brain barrier (BBB)?

They filter blood to produce cerebrospinal fluid. (D) Signup and view all the answers

What is suggested about the origin of microglia?

They develop from white blood cells called macrophages. (B) Signup and view all the answers

How many axon segments can a single oligodendrocyte provide myelin for?

Multiple segments of the same axon or different axons. (A) Signup and view all the answers

What characteristic of the BBB affects the exchange of components in nervous tissue?

It tightly regulates the component exchange due to privileged blood supply. (B) Signup and view all the answers

Which of the following describes the structure and function of ependymal cells?

They form a single layer with tight connections to filter blood. (C) Signup and view all the answers

What is the significance of the name 'oligodendrocyte'?

It describes their structural branching nature. (D) Signup and view all the answers

Which of the following statements is TRUE regarding unipolar neurons?

Their dendrites are directly stimulated by the stimulus. (A), Unipolar neurons are involved in the processing of sensory information. (C) Signup and view all the answers

What is a common characteristic shared by both bipolar and multipolar neurons?

They both have a single axon. (D) Signup and view all the answers

Which of the following is NOT a true statement regarding anaxonic neurons?

They lack an axon, hence the name anaxonic ('without axon'). (D) Signup and view all the answers

Given the information presented, which of the following would be considered a likely role of a unipolar neuron?

Receiving and transmitting sensory information from the skin. (C) Signup and view all the answers

Imagine you are observing a neuron under a microscope. You notice a single axon and multiple dendrites. Based on the text, which of the following classifications would this neuron most likely be considered?

Multipolar (A) Signup and view all the answers

Which of the following examples would be most likely to be classified as a multipolar neuron?

A neuron in the spinal cord transmitting signals to a muscle. (D) Signup and view all the answers

Based on the information provided, which of the following statements is MOST accurate about the classification of neurons?

The classification of neurons can be based on various factors such as structure, location and function. (C) Signup and view all the answers

What is the PRIMARY reason for the difficulty in identifying an axon in an anaxonic neuron under the microscope?

The standard resolution of microscopes used in histology is not sufficient to distinguish axons from dendrites. (A) Signup and view all the answers

What initiates the action potential in a neuron?

The activation of voltage-gated sodium channels at the initial segment (A) Signup and view all the answers

During which phase does the membrane voltage reach approximately +30 mV?

Depolarization phase (A) Signup and view all the answers

What happens during the absolute refractory period?

Voltage-gated sodium channels are inactivated and cannot reopen (A) Signup and view all the answers

What effect does the influx of sodium ions have during the propagation of an action potential?

It depolarizes adjacent sections of the cell membrane (A) Signup and view all the answers

What occurs after the membrane voltage reaches its peak during the action potential?

Activation of voltage-gated potassium channels (C) Signup and view all the answers

How does myelination affect the propagation of an action potential?

It leads to saltatory conduction, increasing propagation speed (C) Signup and view all the answers

What happens to the membrane voltage shortly after hyperpolarization?

It returns rapidly to the resting value (D) Signup and view all the answers

What is the primary reason for the directionality of action potential propagation?

Inactivation of previously opened sodium channels during the refractory period (A) Signup and view all the answers

Study Notes

Nervous System and Nervous Tissue

The neural circuitry of the nervous system is becoming more fully understood, allowing for the integration of technology with the body to restore abilities following trauma.
The nervous system has three primary functions: sensation, integration, and response.
The nervous system is divided into the central nervous system (CNS) and peripheral nervous system (PNS).
The CNS comprises the brain and spinal cord.
The PNS comprises everything else, including nerves, ganglia, and the enteric nervous system.
Nervous tissue is composed of neurons and glial cells.

Basic Structure and Functions

The nervous system is divided into anatomical and functional divisions, with both central and peripheral components.
Gray matter contains cell bodies and dendrites, while white matter contains axons.
Neurons have a cell body (soma), axons, and dendrites, responsible for carrying electrical signals.

Nervous Tissue

Neurons are electrically active cells that release chemical signals to target cells.
Glial cells (glia) provide support for neurons, crucial to their functioning.
There are several types of neurons, classified by their number of processes: unipolar, bipolar, and multipolar.
Unipolar neurons, or pseudo-unipolar neurons in humans, are specialized sensory neurons with a single process emerging from the cell body.
Bipolar neurons have two processes, one on each end of the cell body. Typically found in sensory systems (olfactory and retinal).
Multipolar neurons have numerous dendrites, which receive information from other cells. Most abundant type.

Glial Cells

CNS glial cells include astrocytes (support, BBB), oligodendrocytes (myelination), microglia (immune function), and ependymal cells (CSF production).
PNS glial cells include satellite cells (support for neuron cell bodies in ganglia) and Schwann cells (myelination of nerves).

The Function of Nervous Tissue

The nervous system functions by receiving stimuli (sensation), processing the information (integration), and generating a response (response).
Sensory receptors detect stimuli.
The signal travels along the sensory neuron to the CNS.
The CNS integrates the information and generates a motor command.
The motor command travels along the motor neuron to a target (e.g., muscle).
The target carries out the response.

The Action Potential

Action potentials are electrical signals that travel along axons.
The resting membrane potential is the voltage difference across the membrane when the cell is at rest (-70mV).
Depolarization is the process of membrane potential becoming more positive.
Repolarization is the process of membrane potential returning to its resting value.
The action potential is "all-or-none": it either happens fully or doesn't happen.

Communication Between Neurons

Graded potentials are changes in membrane potential, varying in size.
They can be depolarizing (more positive) or hyperpolarizing (more negative).
Graded potentials summate (add together) to potentially trigger an action potential.
Chemical synapses use neurotransmitters for communication.
Electrical synapses allow ion flow directly between neurons.
Neurotransmitters are released from the axon terminal into the synaptic cleft.
They bind to receptors on the postsynaptic cell, causing a change in membrane voltage.

Important Terms

All the terms including but not limited to: Neurotransmitter, axons, sensory pathways, motor pathways, neurons, electrical synapses, graded potentials, action potential, central nervous system (CNS), peripheral nervous system (PNS) - you should understand the key concepts of all the listed terms from this document.

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Description

Test your knowledge on the functions of myelin insulation and different types of glial cells in the nervous system. This quiz covers key topics such as demyelinating diseases, the roles of Schwann cells, oligodendrocytes, and the overall function of nervous tissue. Challenge yourself with questions related to Multiple Sclerosis and other important concepts.