Ch. 12

Figure 12-2 The Nerve Action Potential Use Figure 12-2 to answer the following questions: Which area of the graph shows when potassium channels open?

3

Figure 12-1 The Neuron Use Figure 12-1 to answer the following questions: The structures labeled "1" are dendrites. Their membranes contain numerous chemically-gated ion channels.

Both statements are true.

Which of the following is not true regarding the establishment of a neuron's resting membrane potential?

Electrical forces do not push sodium ions into the cell.

In one form of presynaptic inhibition the release of ________ inhibits the opening of voltage gated calcium channels in the axon terminus.

GABA

Most neurons lack ________ and so are permanently blocked from undergoing cell division.

centrioles

EPSPs (excitatory postsynaptic potentials) occur when

extra sodium ions enter a cell

Figure 12-1 The Neuron Use Figure 12-1 to answer the following questions: What is contained inside the structure labeled "5"?

neurotransmitter molecules

Axons terminate in a series of fine extensions known as

telodendria

Figure 12-1 The Neuron Use Figure 12-1 to answer the following questions: Identify the structure labeled "4."

telodendria

Branches that may occur along an axon are called

collaterals

The ________ nervous system controls the skeletal muscles.

somatic

Figure 12-2 The Nerve Action Potential Use Figure 12-2 to answer the following questions: In which area of the graph do you see a sudden rush of sodium ions into the neuron?

2

Figure 12-2 The Nerve Action Potential Use Figure 12-2 to answer the following questions: Which area of the graph shows when voltage-gated sodium channels are open?

2

Any stimulus that opens a ________ ion channel will produce a graded potential.

All of the answers are correct

The efferent division of the peripheral nervous system innervates ________ cells.

All of the answers are correct.!!!! glandular heart muscle skeletal muscle smooth muscle

Cholinergic synapses release the neurotransmitter

acetylcholine

The all-or-none principle states that

all stimuli great enough to bring the membrane to threshold will produce identical action potentials.

The site in the neuron where EPSPs and IPSPs are integrated is the

axon hillock

Neurons that have one axon and one dendrite, with the soma in between, are called

bi polar

A neuron whose membrane potential shifts closer to threshold is said to be

facilitated.

Graded potentials

may be either a depolarization or a hyperpolarization.

The myelin sheath that covers many CNS axons is formed by

oligodendrocytes

The nervous tissue outside of the central nervous system composes the ________ nervous system.

peripheral

The rabies virus travels to the CNS via

retrograde axoplasmic transport

Figure 12-2 The Nerve Action Potential Use Figure 12-2 to answer the following questions: Which area of the graph shows when chemically gated sodium channels are open?

1

Figure 12-1 The Neuron Use Figure 12-1 to answer the following questions: Which type of membrane channels are found at label "3"?

both voltage-gated Na+ channels and voltage-gated K+ channels

The most common neuron of the nervous system is the

interneuron.

Which of the following is not involved in creating the resting membrane potential of a neuron?

membrane permeability for sodium ions greater than potassium ions

Which of the following is not a function of the neuroglia?

memory