Lecture 2 Neurophysiology 1

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What type of neuron is primarily found in the central nervous system (CNS)?

Unipolar

Pseudounipolar

Bipolar

Multipolar (correct)

Which structure of a neuron is responsible for transmitting information away from the cell body?

Dendrite

Synapse

Axon (correct)

Cell body

Which type of glial cell is involved in the formation of myelin?

Astrocytes

Oligodendrocytes (correct)

Microglia

Ependymal cells

What is the primary role of sensory neurons?

Carry signals from the PNS to the CNS Signup and view all the answers

What distinguishes glial cells from neurons?

Glial cells are non-neuronal and provide support Signup and view all the answers

The process of converting stimuli into signals is primarily performed by which cells?

Specialized receptors Signup and view all the answers

Which of the following statements is true regarding action potentials?

They are influenced by the concentration of sodium and potassium ions. Signup and view all the answers

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

Form myelin sheaths around neurons Signup and view all the answers

What primarily consists of cell bodies in the nervous system?

Grey matter Signup and view all the answers

What is the role of myelin sheaths in nerve fibers?

Act as an electrical insulator Signup and view all the answers

What is the typical resting membrane potential (RMP) in nerve cells?

–70 to –90 mV Signup and view all the answers

Where are the cell bodies of sensory neurons located?

In ganglia Signup and view all the answers

What maintains the resting membrane potential (RMP) in a cell?

Na+/K+ pump activity Signup and view all the answers

What causes the faster transmission of action potentials in myelinated fibers?

Presence of nodes of Ranvier Signup and view all the answers

What is the primary component of the myelin sheath in the central nervous system (CNS)?

Sphingomyelin Signup and view all the answers

What is the primary function of glial cells wrapped around an axon?

To support and insulate the nerve fiber Signup and view all the answers

What is the primary effect of the influx of Ca2+ during an action potential?

Initiates exocytosis of neurotransmitters Signup and view all the answers

Which process is responsible for the inactivation of neurotransmitters in the synaptic cleft?

Degradation by extracellular enzymes Signup and view all the answers

What type of synapse results in hyperpolarization of the postsynaptic membrane?

Inhibitory synapse Signup and view all the answers

For a postsynaptic potential to reach the threshold required for an action potential, what is generally necessary?

Multiple impulses from excitatory synapses Signup and view all the answers

What is the role of acetylcholine esterase in synaptic transmission?

Deactivates neurotransmitters in the synaptic cleft Signup and view all the answers

What determines whether a neuron will respond to an incoming impulse?

Whether the threshold potential is reached Signup and view all the answers

Which mechanism allows neurotransmitters to be recycled after they are used?

Endocytosis Signup and view all the answers

What characterizes excitatory postsynaptic potentials (EPSP)?

They result from the entry of Na+ into the postsynaptic neuron Signup and view all the answers

What is the primary role of the Na+/K+ pump in maintaining the resting membrane potential (RMP)?

It maintains concentrated gradients of Na+ and K+. Signup and view all the answers

What initiates the opening of voltage-gated ion channels during the action potential process?

A change in membrane potential reaching a threshold. Signup and view all the answers

What is the term for the period during which a neuron cannot be re-stimulated?

Refractory period Signup and view all the answers

During depolarization, which ion primarily rushes into the cell?

Sodium (Na+) Signup and view all the answers

How does myelination affect the conduction of action potentials in axons?

It enables saltatory conduction at nodes of Ranvier. Signup and view all the answers

Which of the following describes the 'all-or-none' rule of nerve cells?

Once the threshold is met, an action potential is generated at a fixed amplitude. Signup and view all the answers

What role do neurotransmitters play in synaptic transmission?

They convert electrical signals into chemical signals. Signup and view all the answers

What is hyperpolarization in the context of an action potential?

An increase in the negativity of the membrane potential. Signup and view all the answers

Which ions are involved in the primary depolarization and repolarization phases of action potentials?

Na+ and K+ Signup and view all the answers

What characterizes ligand-gated channels compared to voltage-gated channels?

They require neurotransmitters to bind to specific receptors to open. Signup and view all the answers

What influences the velocity of nerve signal conduction?

The myelin thickness and diameter of the fiber Signup and view all the answers

Where do action potentials primarily occur in myelinated axons?

At the nodes of Ranvier Signup and view all the answers

What is one characteristic of excitatory neurotransmitters?

They typically promote depolarization in the postsynaptic cell. Signup and view all the answers

In the case of the neuromuscular synapse, what neurotransmitter is primarily involved?

Acetylcholine (ACh) Signup and view all the answers