Human Anatomy and Physiology : Help with Neuroglia Physiology

Study concepts, example questions & explanations for Human Anatomy and Physiology

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Example Questions

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Example Question #1 : Help With Neuroglia Physiology

Which of the following support cells myelinates the axons of the peripheral nervous system?

Possible Answers:

Schwann cells

Ependymal cells

Oligodendrocytes

Astrocytes

Correct answer:

Schwann cells

Explanation:

There are two types of support cells that myelinate axons in the nervous system: oligodendrocytes and Schwann cells. The difference between these two cell types is their location in the nervous system. Oligodendrocytes myelinate axons in the central nervous system, and Schwann cells myelinate axons in the peripheral nervous system.

Ependymal cells secrete cerebrospinal fluid and astrocytes help form and regulate the blood-brain barrier.

Example Question #2 : Help With Neuroglia Physiology

What is the function of myelin?

Possible Answers:

Insulate axons

Respond to tissue damage

Decrease conduction velocity down an axon

Provide protection for neural fibers

Correct answer:

Insulate axons

Explanation:

Myelin insulates axons and functions to increase the speed of a nerve impulse as it travels down an axon. Central nervous system axons are myelinated by oligodendrocytes, whereas peripheral nervous system axons are myelinated by Schwann cells. When an action potential interfaces with a myelinated axon, sodium influxes at the regions between myelin sheathing. These regions without myelin are called nodes of Ranvier. The depolarization at a node can quickly be transmitted to the next node, rather than traveling fluidly down the whole axon. This process of jumping between nodes is known as saltatory conduction, and serves to greatly increase the transmission of action potentials. Loss of myelin can lead to numerous neurodegenerative disorders.

Example Question #3 : Help With Neuroglia Physiology

Which of the following is NOT a property of an oligodendrocyte?

Possible Answers:

Myelinate axons in the central nervous system

Myelinate muliple axons

Myelinate only one axon

Arise from the neuroectoderm

Correct answer:

Myelinate only one axon

Explanation:

Oligodendrocytes myelinate central nervous system (CNS) axons. Each oligodendrocyte can myelinate up to thirty axons, stretching between neurons. Oligodendroctyes are the predominant type of glial cell in white matter, with the myelin giving them a white appearance. Schwann cells myelinate axons in the peripheral nervous system (PNS), and can only be associated with one neuron per cell.

Example Question #4 : Help With Neuroglia Physiology

Which of the following support cells is responsible for phagocytosis of microbes in the central nervous system?

Possible Answers:

Oligodendrocytes

Astrocytes

Microglia

Ependymal cells

Satellite cells

Correct answer:

Microglia

Explanation:

Microglia are derived from monocytes, which are white blood cells that are found in the blood stream. The microglia are responsible for removing pathogens and cellular debris from the central nervous system.

Astrocytes help form and regulate the blood-brain barrier and ependymal cells secrete cerebrospinal fluid. Satellite cells help modulate the external environment are sensory neurons. Oligodendrocytes are responsible to myelination of the central nervous system.

Example Question #5 : Help With Neuroglia Physiology

Which of the following is not a property of a Schwann cell?

Possible Answers:

Predominant cell type in white matter

All of these are properties of Schwann cells

Increases conduction velocity via saltatory conduction

Arises from neural crest cells

Myelinates only a single axon

Correct answer:

Predominant cell type in white matter

Explanation:

Schwann cells are part of the peripheral nervous system (PNS) and myelinate only a single axon per cell. Schwann cells increase the conduction velocity of nerve impulses down axons via saltatory conduction between nodes of Ranvier. The nerve impulse jumps from node to node, rather than fluidly traveling down the axon.

 Oligodendrocytes, which myelinate central nervous system axons, are the predominant glial cell in white matter.

Example Question #6 : Help With Neuroglia Physiology

Which of the following adds the myelin sheath to neurons of the central nervous system?

Possible Answers:

Oligodendrocytes

Schwann cells

Dendrites

Axon hillock

Neuron soma

Correct answer:

Oligodendrocytes

Explanation:

The myelin sheath is responsible for the fast proagation of signals down the neuronal tissue. It is a fatty layer that insulates the neuron, causing the action potential signal to jump or skip over portions of the axon, speeding up transmission. This myelin sheath gets laid down by oligodendrocytes in the central nervous system and by Schwann cells in the peripheral nervous system. Each other answer choice is a different part of the neuron itself; the neuron cannot synthesize its own myelin sheath.

Example Question #7 : Help With Neuroglia Physiology

What type of cells set up the myelin sheath in the peripheral nervous system? 

Possible Answers:

Ependymal cells

Oligodendrocytes 

Schwann cells 

Astrocytes 

Microglial cells 

Correct answer:

Schwann cells 

Explanation:

The myelin sheath is the electrical insulator around neurons that increase the conduction velocity. In the peripheral nervous system, Schwann cells are responsible for the production of the myelin sheath. It is important to note that in the central nervous system, oligodendrocytes are responsible for producing the myelin sheath. The other cell types are neuroglia that have the following basic functions: astrocytes - support of neurons, damage repair, nutrient delivery/waste removal, ependymal cells - production of cerebrospinal fluid, microglia - immune-like neuroglia. 

Example Question #8 : Help With Neuroglia Physiology

Which type of neuroglial cell is star-shaped and takes up 50% of the cells in the brain?

Possible Answers:

Ependymal cells

Astrocytes 

Oligodendrocytes 

Schwann Cells 

Microglia cells 

Correct answer:

Astrocytes 

Explanation:

Astrocytes are star-shaped cells found between neurons and blood vessels. They cover almost all of the capillaries in the brain and make contact with surfaces of neurons. They make up approximately 50% of the cells in the brain. Astrocytes are responsible for supporting neurons by maintaining the extracellular fluid, facilitating nutrient delivery and waste removal to and from neurons, maintaining the blood-brain barrier, and repairing damaged cells in the central nervous system. Schwann cells and oligodendrocytes are responsible for myelinating axons in the peripheral nervous system and central nervous system, respectively. Microglia are specialized macrophages that remove cellular debris, infectious agents and damaged neurons. Ependymal cells are epithelial-like glial cells in the central nervous system that line the ventricles and produce cerebrospinal fluid.

Example Question #9 : Help With Neuroglia Physiology

Which cell produces myelin in the central nervous system (CNS)?

Possible Answers:

Schwann cells

Oligodendrocytes

Astrocyte

Microglia

Correct answer:

Oligodendrocytes

Explanation:

While both Oligodendrocytes and Schwann cells make myelin, oligodendrocytes produce myelin for the central nervous system (CNS), while Schwann cells make myelin in the peripheral nervous system (PNS). Oligodendrocytes are a type on neuroglia; their main function is to provide both support and insulation to axons of the CNS via the production of a myelin sheath. A single oligodendrocyte can extend processes to 50 axons, wrapping myelin around each axon. While Schwann cells provide a similar function, they can only wrap around one axon. 

Example Question #10 : Help With Neuroglia Physiology

Which part of a neuron is responsible for receiving information?

Possible Answers:

Soma

Axon hillock

Dendrite

Node of Ranvier

Axon

Correct answer:

Dendrite

Explanation:

Dendrites are the "branchlike" projections off of the soma of a neuron. Their purpose is to pick up information that can later be sent through the axon with action potentials. The more branching that is present allows greater surface area along with increased potential of picking up signals.

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