Electrophysiology and Neural Tissue Review

Study Notes

Electrophysiology and Neural Tissue Key Concepts

Microglial cells do not produce myelin; that function is performed by oligodendrocytes in the CNS.
Hyperpolarization occurs when a cell becomes more negative, moving past its resting potential.
Resting membrane potential is primarily determined by leak potassium channels, not leak sodium channels.
The parasympathetic nervous system is part of the efferent portion, not the afferent part of the peripheral nervous system.
Terminal buttons, or axon terminals, are responsible for releasing neurotransmitters into the synapse.
Action potentials travel unidirectionally, typically from the axon hillock toward the axon terminals.
Larger diameter neurons propagate action potentials at a faster velocity due to lower internal resistance.
Voltage-gated potassium channels are responsible for the rapid repolarization phase, not the upstroke of action potentials.
The afterhyperpolarization phase results from prolonged outflow of K+ ions through voltage-gated potassium channels.
Activation of ligand-gated Cl- channels generally leads to inhibitory postsynaptic potentials (IPSPs), not excitatory (EPSPs).

Blood-Brain Barrier and Ion Concentrations

The "tightness" of the blood-brain barrier is primarily due to astrocytes, a type of glial cell.
Sodium equilibrium potential can be calculated with given concentrations; using Na+ concentrations of 145 mEq/L extracellular and 14 mEq/L intracellular yields approximately +62mV.
The resting membrane potential is closest to the equilibrium potential for potassium ions, as it is the most permeable ion at rest.
Hyperkalemia (elevated potassium levels) causes the resting membrane potential to become more positive (depolarization).

Neuron Function and Neurotransmission

Neurotransmitter release is inhibited by blocking Ca2+ influx at the axon terminal, which is critical for vesicle fusion and neurotransmitter exocytosis.
During the relative refractory period, sodium channels can be inactivated, while some may be recovering to a closed state; K+ is typically still leaving the neuron.
Chemicals that stimulate action potentials in postsynaptic cells are classified as neurotransmitters.
IPSPs result from outflow of K+ ions and the inflow of Cl- ions; influx of Na+ or opening of Ca2+ channels typically produce EPSPs.

Description

Test your knowledge on electrophysiology and neural tissue through this quiz. Answer true or false to various statements about microglial cells, resting membrane potential, and the nervous system. Perfect for students studying biology or neuroscience.