Chapter 12 Homework Quesitons

A recently depolarized area of a cell membrane cannot generate an action potential because of the

Absolute Refractory Period

Neurons that carry signals from the CNS to skeletal muscle for contraction would be classified as _____________ neurons.

Efferent

Greater current flow is possible with larger resistance and a lower voltage (T/F)

False

In neurons, protein pumps allow substances to move passively down their concentration gradients (T/F)

False

The endoneurium wraps around groups of fasicles to form a nerve (T/F)

False

The inside of the cell membrane becomes negative at the time of an action potential (T/F)

False

Depolarization is initiated by a stimulus that makes the membrane potential

Positive

When sodium enters the neuron via chemically gated sodium channels, the membrane will depolarize. Therefore, the membrane potential will become more____

Positive

An inhibitory post synaptic potential (IPSP) will make

The membrane potential of a neuron's inner cell membrane more negative

On a typical neuron, the axon is usually longer in length than the dendrites (T/F)

True

Postsynaptic neurons can generate both inhibitory and excitatory postsynaptic potentials simultaneously (T/F)

True

Sodium has a higher concentration outside the cell than within (T/F)

True

The inflow of sodium ions into the intracellular fluid causes depolarization of the neuron's inner cell membrane (T/F)

True

The leakage of potassium plays a more significant role in the resting membrane potential than the leakage of sodium (T/F)

True

On a graph of an action potential, the small depolarizations that lead to threshold are from

excitatory postsynaptic potentials (EPSPs).

If all the sodium leakage channels were removed from the cell membrane of a neuron,

intracellular sodium levels would increase.

The vagus nerve contains afferent and efferent neurons, therefore it is an example of a(n) __________ nerve.

mixed

Depolarization of a cell membrane occurs because

more sodium ions diffuse into the cell than potassium ions diffuse out of it.