30 Questions
Which type of nerve fibers have the fastest conduction velocity?
A fibers
Which type of fibers are responsible for sharp pain?
Delta (δ) fibers
What is the main characteristic of nonmyelinated nerves?
They have high-electrical resistance cell membranes
What is the primary function of Beta (β) fibers?
Awareness of position/equilibrium
Which type of nerve fibers are the most numerous fiber type in the Peripheral Nervous System (PNS)?
C fibers
What is a characteristic feature of A-Delta fibers?
They are myelinated
What type of fibers are primarily responsible for sharp dental pain?
A-delta fibers
Which type of fibers are the most numerous and usually unmyelinated?
C fibers
Which type of fibers are lightly myelinated motor fibers?
A fibers
In the oral cavity, which type of fibers are found abundantly?
A-delta fibers
What principle ensures that the nerve impulse will travel the length of the nerve fiber at its initial strength?
All-or-none firing principle
Why do A-delta fibers require more anesthetic volume for complete nerve blockage?
They are larger in size and myelinated
What happens during the process of depolarization?
The cell becomes more positively charged inside and more negatively charged outside.
What is the role of ion-gated channels during depolarization?
They open to allow more sodium ions to enter the cell.
What is the average electric potential at which an action potential is created?
15-20 mV
What is the role of neurotransmitters in the transmission of signals between neurons?
Neurotransmitters are released from the presynaptic cell and bind to receptors on the postsynaptic cell, transmitting the signal.
How do local anesthetics work as sodium channel blockers?
Local anesthetics bind to the sodium channels, causing them to close and prevent sodium ions from entering the nerve.
What is the difference between excitatory and inhibitory neurotransmitters?
Excitatory neurotransmitters increase the likelihood of an action potential, while inhibitory neurotransmitters decrease it.
Which of the following is responsible for forming the myelin sheath around axons in the central nervous system (CNS)?
Oligodendrocytes
What is the function of the Nodes of Ranvier along myelinated axons?
To facilitate saltatory conduction of action potentials
Which of the following statements about nerve regeneration is correct?
Myelinated axons in the peripheral nervous system (PNS) can regenerate, but unmyelinated axons cannot.
Which of the following best describes saltatory conduction?
The rapid propagation of action potentials from one Node of Ranvier to the next along myelinated axons
What is the primary cause of the neurological symptoms in multiple sclerosis?
Demyelination of axons in the central nervous system
Which of the following statements about nerve regeneration in the central nervous system (CNS) is correct?
Neither myelinated nor unmyelinated axons in the CNS can regenerate
What is the primary mode of action of local anesthetics?
Inhibiting sodium influx through voltage-gated sodium channels in the neuronal cell membrane
Which type of nerve fibers are more sensitive to local anesthetics?
Both small myelinated and non-myelinated axons
Why do larger nerve fibers require more time for the local anesthetic to take effect?
More nodes of Ranvier need to be blocked for complete conduction block
What happens when local anesthetics are administered?
Depolarization of the nerve membrane is prevented
Which order do local anesthetics block nerve fiber conduction?
Small myelinated axons, non-myelinated axons, large myelinated axons
What is the significance of the nodes of Ranvier in the action of local anesthetics?
They are the sites where local anesthetics bind to sodium channels
Learn about the structure of myelinated axons in the central nervous system, including the role of oligodendrocytes and Nodes of Ranvier. Understand how myelination and Nodes of Ranvier contribute to rapid electrical impulse transmission.
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