Exam 13: A: Nervous System Cells

In a contralateral reflex arc,the receptors and effectors are located on opposite sides of the body.

Electrical synapses can be found in muscle tissue.

Small,lipid-soluble molecules can diffuse easily across the blood-brain barrier.

One distinction between ipsilateral and contralateral reflexes is that contralateral reflexes have interneurons and ipsilateral reflexes do not.

The function of the parasympathetic nervous system is commonly described as that which prepares the body for "fight-or-flight."

Cranial nerves are considered part of the central nervous system.

Whether a group of nerve fibers is called a nerve or a tract depends on its location.

The afferent pathways of the autonomic nervous system stimulate muscles and do not have a sensory component.

In depolarization the membrane potential moves toward zero,whereas in hyperpolarization the membrane potential moves away from zero.

The nervous system consists of the brain,spinal cord,and nerves.

All neurotransmitters are organic molecules.

No impulse can be sent if a nerve cell is in the absolute refractory period.

Ependymal cells act like epithelial cells in the CNS,forming thin sheets that line cavities.

During the nerve impulse,the internal charge of the neuron becomes briefly positive.

The sodium-potassium pump actively pumps three potassium ions out of the neuron and two sodium ions into the neuron.

The blood-brain barrier is so effective that only water molecules are able to cross it.

Astrocytes,the star-shaped glia cells,may be able to transmit information along "astrocyte pathways."

The name for the astrocyte comes from its shape.

A neurotransmitter can be excitatory or inhibitory,not both.

Cocaine produces a temporary feeling of well-being by blocking the release of dopamine.