38 Questions
What is the effect of myelination on the conduction of action potentials along the axon?
It increases the speed of impulse conduction
What is the primary function of the synaptic cleft in synaptic transmission?
To act as the site for intraneuronal communication
Where are the voltage-sensitive Na+ and K+ channels located in myelinated nerve fibers?
Clustered in high density at the node of Ranvier
What is the function of the myelin sheath in the central nervous system?
It insulates the axon, allowing for faster conduction of action potentials
What triggers the release of neurotransmitters from the presynaptic terminal?
The electrotonic invasion of the action potential into the terminal
What is the role of Ca2+ ions in synaptic transmission?
To trigger the release of neurotransmitters from the presynaptic terminal
What is the characteristic of the smallest axons?
They are unmyelinated
What is the effect of the thickness of the myelin sheath on the conduction velocity of the nerve impulse?
The thicker the myelin sheath, the faster the conduction velocity
What is the primary difference between electrical and chemical synaptic transmission?
The direction of transmission
What is the characteristic of the propagation of action potentials in unmyelinated fibers?
It occurs in a continuous manner along the axon
What is the term for the release of neurotransmitters from the presynaptic terminal into the synaptic cleft?
Exocytosis
What is the term for the space between two neurons where chemical transmission occurs?
Synaptic cleft
What is the role of the node of Ranvier in the propagation of action potentials?
It is the site of voltage-gated sodium channel clustering
What is the type of cell that produces myelin in the central nervous system?
Oligodendrocyte
What is the role of synaptic vesicles in synaptic transmission?
To store and release neurotransmitters into the synaptic cleft
What is the term for the process by which neurotransmitters bind to receptors on the post synaptic neuron?
Binding
Where are K+ channels typically localized in a myelinated axon?
Internodal area
What is the term for the mode of conduction of action potential in myelinated axons?
Saltatory conduction
What is the most common type of synapse, representing 80-95% of all synapses?
Axodendritic synapses
What is the primary function of axoaxonic synapses?
Modulating transmitter release by the postsynaptic axon
What is the term for the point of functional contact between axons and skeletal muscle?
Neuromuscular junction
What is the primary direction of information flow in synaptic transmission?
From the presynaptic neuron to the postsynaptic neuron
What type of synaptic transmission is rare in humans and common in invertebrates?
Electrical transmission
What is the term for the specialized complex that allows for the transmission of information between neurons?
Synaptic junction
What is the primary mechanism of neurotransmitter action at the synapse?
Opening or closing of ion channels
What is the primary defect in myasthenia gravis?
Attack on the acetylcholine receptor in the postjunctional folds
What is the primary symptom of myasthenia gravis?
Skeletal muscle weakness and fatigability
What is the effect of antibodies on the acetylcholine receptor in myasthenia gravis?
Structural changes in the postjunctional folds
What is the primary treatment for myasthenia gravis?
Inhibiting acetylcholinesterase to increase acetylcholine in the synaptic cleft
What is the characteristic of Lambert-Eaton syndrome?
Presynaptic disorder affecting neuromuscular transmission
What is the effect of repetitive stimulation on muscle action potentials in myasthenia gravis?
Progressive decrease in muscle action potentials
What is the status of nerve fibers in myasthenia gravis?
Intact nerve fibers
In Lambert-Eaton myasthenic syndrome, muscle weakness and fatigability predominantly affects which musculature?
Proximal limb and trunk musculature
What is the primary site of lesion in demyelinating diseases such as Guillain-Barré syndrome?
CNS oligodendroglia and PNS Schwann cells
What is the characteristic electrophysiologic finding in Guillain-Barré syndrome?
Very slow nerve conduction velocities and reduced compound action potential amplitude
What is the typical pattern of weakness progression in Guillain-Barré syndrome?
Ascending paralysis, starting from the legs
What is the potential complication of Guillain-Barré syndrome?
Respiratory failure
What is the process by which recovery occurs in Guillain-Barré syndrome?
Remyelination
Understanding myelination in the Central Nervous System, its production by Oligodendrocytes, and its effects on action potential conduction along axons.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
