Bio 12.1 Nervous System: Neurons and Glial Cells

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Questions and Answers

What is the primary function of neurons in the nervous system?

To receive, integrate, and transmit information (correct)

To provide structural support to other cells

To store energy for cellular processes

To facilitate blood flow to the brain

Which part of a neuron is primarily involved in signal transmission?

Soma

Synapse

Dendrite

Axon (correct)

Which of the following describes the function of dendrites?

Protecting the neuron from damage

Signal transmission to other neurons

Production of neurotransmitters

Information reception from other neurons (correct)

What is the role of glial cells in the nervous system?

To provide insulation and support to neurons Signup and view all the answers

What characterizes bipolar neurons?

One dendrite and one axon Signup and view all the answers

Which component of the neuron is responsible for integrating incoming signals?

Soma Signup and view all the answers

What is a unique feature of unipolar neurons?

They consist of a single extension that functions as both dendrite and axon. Signup and view all the answers

What is the axon hillock's significance in a neuron?

It initiates action potentials. Signup and view all the answers

What role do sensory (afferent) neurons primarily serve in the nervous system?

They carry information from the periphery to the CNS. Signup and view all the answers

Which type of neuron is primarily responsible for connecting two neurons within the central nervous system?

Interneurons Signup and view all the answers

What is the primary function of myelinated neurons in the nervous system?

To transmit information via electrical impulses more efficiently Signup and view all the answers

What is the role of mitochondria in neurons?

To generate ATP for cellular energy demands Signup and view all the answers

Which of the following statements about myelination is correct?

The myelin sheath is formed by layers of glial cell membranes. Signup and view all the answers

What is the main energy-consuming process that neurons engage in?

Pumping ions across the plasma membrane Signup and view all the answers

Which parts of the neuron are typically not myelinated?

Cell bodies and dendrites Signup and view all the answers

What distinguishes motor (efferent) neurons from sensory (afferent) neurons?

Motor neurons convey signals from the CNS to the periphery. Signup and view all the answers

What role do microglia play in the central nervous system (CNS)?

They transform into macrophages to respond to damage or infection. Signup and view all the answers

Which of the following functions are NOT performed by astrocytes?

Phagocytosing pathogens and damaged cells. Signup and view all the answers

What is the function of Schwann cells in the peripheral nervous system (PNS)?

They increase the speed of electrical impulse conduction along a single axon. Signup and view all the answers

Which cells in the PNS provide structural support to neuron cell bodies?

Satellite cells Signup and view all the answers

How do microglia contribute to the immune response within the CNS?

By preventing other immune cells from entering the CNS. Signup and view all the answers

What is the role of the nodes of Ranvier in myelinated axons?

They allow electrical impulses to jump along the axon. Signup and view all the answers

Which type of glial cell is responsible for myelinating peripheral nervous system neurons?

Schwann cells Signup and view all the answers

What is the primary effect of demyelination on signal transmission?

It can slow down or block signal transmission. Signup and view all the answers

How does myelination affect ion movement in neurons?

It concentrates ion movement at specific sites. Signup and view all the answers

What is the process called in which electrical impulses 'jump' along a myelinated axon?

Saltatory conduction Signup and view all the answers

Which of the following glial cells produce cerebrospinal fluid?

Ependymal cells Signup and view all the answers

What happens to the myelin sheath in demyelinating diseases?

It gets damaged or removed. Signup and view all the answers

What effect does myelination have on the capacitance of an axon?

Decreases capacitance Signup and view all the answers

Study Notes

Nervous System: Cells

The nervous system is composed of neurons and glial cells.
Neurons transmit information via electrochemical signaling.
Glial cells provide support to neurons.
- Some glial cells, like oligodendrocytes and Schwann cells, modify neurons by providing myelin, an electrically insulating layer.

Neuron Structure and Function

Neurons are specialized for receiving, integrating, and transmitting information.
Neurons have three main parts:
- Soma: Cell body containing the nucleus and participating in information reception and integration.
- Dendrites: Neuron extensions specialized for signal reception.
- Axons: Neuron extensions specialized for signal transmission.
- Axon hillock: Region where the axon originates from the soma.
- Axon terminal: End of the axon, where signal transmission occurs.
Neurons can be classified based on their morphology:
- Bipolar neurons: Single dendrite and a single axon.
- Multipolar neurons: More than one dendrite and a single axon.
- Unipolar neurons: Cell body located to the side of a single extension formed from the fusion of a dendrite and axon.
Neurons can also be classified based on their function and location:
- Sensory neurons (afferent): Transmit information from the periphery to the CNS.
- Motor neurons (efferent/somatic): Transmit signals from the CNS to the periphery.
- Interneurons: CNS neurons connecting two neurons.

Myelin Sheath

Myelinated neurons have an electrically insulating sheath called myelin around their axons.
Unmyelinated neurons lack this layer.
Myelin consists of multiple layers of a glial cell phospholipid membrane wrapped around the axon.
Myelination alters ion and nutrient transport along axons.
Myelinating cells provide nutrients to myelinated regions.
The myelin layer is interrupted at small, regularly spaced sites called the nodes of Ranvier, which are rich in ion channels.
Myelination causes electrical impulses to "jump" along the axon, a process known as saltatory conduction.
Oligodendrocytes: Myelinate CNS neurons.
Schwann cells: Myelinate PNS neurons.

Glial Cells

Glial cells provide support, protection, and optimization of neuronal impulse transmission.
Ependymal cells: Line CNS compartments, forming a barrier and producing cerebrospinal fluid.
Oligodendrocytes: Myelinating cells in the CNS.
Microglia: Immune cells in the CNS that can transform into macrophages to phagocytose pathogens and damaged cells.
Astrocytes: Network of cells connected by gap junctions that perform diverse roles:
- Regulate blood flow.
- Form the blood-brain barrier.
- Regulate chemical composition near synapses.
- Exchange metabolic substrates with neurons.
Schwann cells: Myelinating cells in the PNS.
Satellite cells: Nonmyelinating Schwann cells in the PNS that provide structural support and nutrients to neuron cell bodies.

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Description

Explore the structure and function of neurons and glial cells in this quiz focused on the nervous system. Understand the roles of various neuron parts and their significance in signal transmission and support. Test your knowledge on how these cells interact to maintain the body's communication system.