Neuroglia Biology Quiz

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Questions and Answers

What percentage of the central nervous system cells are neurons?

50%

25%

10% (correct)

Which type of glial cell is primarily involved in myelination in the central nervous system?

Ependymal cells

Astrocytes

Microglia

Oligodendrocytes (correct)

Which function is NOT associated with astrocytes?

Providing scaffolding for neural development

Taking up K+ from extracellular fluid

Myelinating peripheral axons (correct)

Forming the blood-brain barrier

What is the role of microglia in the central nervous system?

Serve as phagocytes and part of the immune system Signup and view all the answers

Which type of glial cell surrounds blood capillaries and takes up glucose from the blood?

Astrocytes Signup and view all the answers

What is the primary role of Schwann cells in the nervous system?

Myelination of peripheral nervous system axons Signup and view all the answers

Which statement about the myelination of axons is accurate?

Myelin consists of layers of lipid membranes Signup and view all the answers

How do glial cells modulate synaptic action?

By regulating neurotransmitter release and uptake Signup and view all the answers

What is the primary function of afferent neurons?

To convey information from the body to the central nervous system Signup and view all the answers

Which neuron classification has two processes extending from its cell body?

Bipolar neurons Signup and view all the answers

What type of transport is retrograde transport?

Transport from the nerve ending back to the cell body Signup and view all the answers

What type of neuron is specifically adapted for sensory functions and can sometimes appear as pseudo-unipolar?

Unipolar neurons Signup and view all the answers

What is the main role of efferent neurons within the nervous system?

To transmit information from the central nervous system to effector cells Signup and view all the answers

How do linking proteins, such as dynein and kinesin, function in the context of neurons?

As motors for axonal transport of substances Signup and view all the answers

Which functional class of neurons is primarily responsible for connecting neurons within the central nervous system?

Interneurons Signup and view all the answers

Which of the following best describes multipolar neurons?

They possess a single axon and multiple dendrites extending from the cell body. Signup and view all the answers

What distinguishes the functions of afferent pathways from efferent pathways?

Afferent pathways send signals to the brain, while efferent pathways send signals from the brain. Signup and view all the answers

Which structure of a neuron is primarily responsible for receiving signals from other neurons?

Dendrites Signup and view all the answers

How are neurons primarily classified?

By their function as motor or sensory. Signup and view all the answers

What is the role of neurotransmitter modulation in neural communication?

To enhance or inhibit the signaling between neurons. Signup and view all the answers

Which type of glial cell is primarily involved in the maintenance of the blood-brain barrier?

Astrocytes Signup and view all the answers

What is a characteristic feature of the cell body of a neuron?

It houses the nucleus and organelles for protein synthesis. Signup and view all the answers

What type of neuron would likely send information from sensory receptors to the central nervous system?

Afferent neurons Signup and view all the answers

Which structural component of a neuron conducts impulses away from the cell body?

Axon Signup and view all the answers

Study Notes

Glial Cells

Glial cells are also called neuroglia and account for 90% of the central nervous system.
Glial cells provide physical and metabolic support to neurons.
Glial cells maintain the ionic milieu of nerve cells.
Glial cells help modulate the rate of nerve signal propagation.
Glial cells modulate synaptic action by controlling the uptake of neurotransmitters.
Glial cells provide a scaffold for some aspects of neural development.

Types of Glial Cells

Microglia act as phagocytes and are part of the brain’s immune system.
Astrocytes (aster = star) are large stellate cells with numerous cytoplasmic processes that radiate outward.
Astrocytes take up K+ from the extracellular fluid.
Astrocytes take up some neurotransmitters.
Astrocytes take up glucose from the blood.
Astrocytes appear to be needed for the formation of synapses in the CNS.
Astrocytes induce the formation of the blood-brain barrier.
Oligodendrocytes myelinate axons of the central nervous system.
Schwann cells myelinate axons of the peripheral nervous system.

Myelin

The axons of most neurons are covered by myelin.
Myelin consists of 20 to 200 layers of highly modified plasma membrane wrapped around the axon.
Oligodendrocytes form myelin in the brain and spinal cord.
Each oligodendrocyte can form myelin on as many as 40 axons.
Schwann cells form myelin in the peripheral nervous system.
Schwann cells form one individual myelin sheath.

Axon Transport

Axons carry information from the cell body to its target cells.
Cytoplasmic proteins, organelles, and other materials are transported along the axons.
Transport uses microtubules and specialized proteins called “motors.”
Retrograde transport carries materials in the opposite direction (from the nerve ending to the cell body).
Retrograde transport occurs at about 200 mm/day.
This is the route by which certain harmful substances, such as tetanus toxin, herpes, and some viruses can enter the central nervous system.

Neuron Classification

Neurons can be classified according to their function or structure.
Unipolar neurons have one process, with different segments serving as receptive surfaces and releasing terminals.
Bipolar neurons have two specialized processes: a dendrite that carries information to the cell and an axon that transmits information from the cell.
Multipolar neurons have one axon and many dendrites.
Neurons can be divided into three functional classes: afferent neurons, efferent neurons, and interneurons.
Afferent neurons convey information from the tissues and organs of the body into the central nervous system.
Efferent neurons convey information from the central nervous system out to effector cells (muscle or gland cells or other neurons).
Interneurons connect neurons within the central nervous system.

Nervous System Organization

The nervous system is divided into two parts: the central nervous system (CNS) and the peripheral nervous system (PNS).
The CNS includes the brain and spinal cord.
The PNS connects the body to the brain and spinal cord.
The PNS includes 12 pairs of cranial nerves and 31 pairs of spinal nerves.
Cranial nerves connect to the brain.
Spinal nerves connect to the spinal cord.
Nerves are bundles of sensory and motor neurons held together by connective tissue.

Functional Components of the PNS

The PNS is responsible for sensory inputs and motor outputs that can be categorized as somatic or visceral.
Sensory inputs can also be classified as general or special.

Anatomic Organization of PNS Neurons

Ganglia are collections of nerve cell bodies outside of the CNS.
Nerves are bundles of axons supported by connective tissue.
Spinal nerves connect to the spinal cord.
Cranial nerves connect to the brain.

Neuron Anatomy

The basic unit of the nervous system is the neuron.
Neurons occur in a wide variety of shapes and sizes.
All neurons share features that allow cell-to-cell communication.
A neuron can be divided into four regions: cell body, dendrites, an axon, and axon terminals.
The cell body houses the nucleus and components required for protein synthesis.
Dendrites are branched outgrowths of the cell body that receive inputs from other neurons.
The axon carries output to its target cells.

Neuron Anatomy Continued

Dendrites increase the cell's surface area.
This increases the cell's capacity to receive signals from other neurons.

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Description

Test your knowledge on glial cells, their functions, and types in the central nervous system. This quiz covers the roles of various glial cells such as microglia, astrocytes, and oligodendrocytes. Perfect for students looking to enhance their understanding of neurobiology.