Exam 13: A: Nervous System Cells

A neurotransmitter can be either excitatory or inhibitory depending on the postsynaptic receptor.

Excitatory neurotransmitters are most likely to initiate an action potential.

Pathways from the autonomic nervous system that leave the central nervous system from the brain would be sympathetic pathways.

If the threshold potential is surpassed,the full peak of the action potential is always reached.

Satellite cells are oligodendrocytes that surround the cell bodies of neurons in the central nervous system.

Microglia are associated with the formation of the blood-brain barrier.

There is a time when a neuron will not send a nerve impulse no matter how strong the stimulus is.

The basic tenet of the neuron doctrine is that neurons function as independent units connected by chemical synapses.

If a membrane exhibits a membrane potential,it is said to be polarized.

Rapid succession stimulation of a postsynaptic neuron by a synaptic knob is called an ipsilateral reflex.

The neuron is able to maintain an internal negative charge by pumping out sodium (Na⁺)and pumping in chlorine (Cl-).

In an adult,brain cells do not undergo mitosis,except to replace neurons that have been damaged or destroyed.

When "central" and "peripheral" are used as directional terms in the nervous system,a nerve fiber may be called peripheral if it extends from the cell body away from the central nervous system.

Microtubules and microfilaments provide a type of "railway" for the rapid transport of organelles to and from the ends of the neuron.

Myelinated fibers conduct impulses faster than unmyelinated fibers.

An electrical synapse occurs when a strong action potential is able to arc across a small synaptic cleft.

The nervous system can be divided according to structure,direction of information flow,and speed of conduction.

Most injuries to the brain and spinal cord cause permanent damage.

In a myelinated fiber,the action potential jumps from one node of Ranvier to the next.

Dendrites have many synaptic knobs so they can receive impulses from several other neurons at the same time.