Introduction to the Nervous System and Nervous Tissue

Twenty-five fill-in-the-blank flashcards covering key concepts from Nervous Tissue, Electrophysiology, and Neuronal Synapses.

The division of the nervous system that splits into sympathetic and parasympathetic branches is the __ division.

autonomic

A typical neuron’s resting membrane potential is approximately __ mV.

-70

Myelinated axons conduct impulses rapidly via __ conduction.

saltatory

The fine terminal branches at the end of an axon are called __.

telodendria

Phagocytic neuroglial cells in the CNS are known as __.

microglial cells

The neuroglial cells that myelinate axons in the PNS are __ cells.

Schwann

Electrical synapses connect cells through __ junctions.

gap

During a chemical synapse, influx of __ ions into the presynaptic terminal triggers neurotransmitter release.

calcium (Ca²⁺)

The space between the pre- and postsynaptic membranes in a chemical synapse is the __.

synaptic cleft

A graded depolarization that moves the postsynaptic membrane potential closer to threshold is called an __.

EPSP (excitatory postsynaptic potential)

Removal of extracellular calcium __ the amount of neurotransmitter released.

decreases

Increasing axonal myelination __ the time between successive action potentials.

decreases

Greater stimulus intensity is encoded by an increase in the __ of action potentials.

frequency

During the relative refractory period, a second action potential can be generated only if the stimulus is __ threshold.

above

Raising extracellular potassium makes the resting membrane potential __ negative.

less

The minimal membrane voltage that must be reached to initiate an action potential is the __ voltage.

threshold

Among the sensory receptors tested, the one that responds to a chemical stimulus is the __ receptor.

olfactory

The toxin tetrodotoxin causes death because it blocks voltage-gated __ channels, preventing action potentials.

sodium (Na⁺)

Multiple sclerosis damages the CNS myelin produced by __ cells.

oligodendrocytes

The point on the neuron where the action potential is usually initiated is the __.

axon hillock

A rapid rise in membrane potential due to opening of voltage-gated Na⁺ channels is called __.

depolarization

The return of the membrane potential toward resting levels, primarily via K⁺ efflux, is termed __.

repolarization

In a resting neuron, ion gradients favor diffusion of __ ions into the cell.

sodium (Na⁺)

The neuron that releases neurotransmitter into a synapse is the __ neuron.

presynaptic

Membranous sacs in axon terminals that store neurotransmitter are called __.

synaptic vesicles