Chapter 12 study questions

A nerve is part of the ____ nervous system.

peripheral

An inhibitory postsynaptic potential results from the opening of

potassium and/or chloride channels

Membrane molecules that use the energy of ATP to move ions against a concentration gradient are called

pumps

_____ is the return of polarity from positive back to negative (the RMP).

repolarization

The function of a neuron is dependent on

resting membrane potentials changing

glial cells are ______ than neurons

smaller

Normally, sodium and potassium leakage channels differ because ___________________.

sodium ions diffuse through leakage channels into the cell, but potassium ions diffuse through leakage channels out of the cell

A damaged axon within the PNS can regenerate if ______.

some neurilemma remains

Vesicles involved in retrograde transport are moving ______ the cell body.

toward

If a sub threshold value is reached on an axon membrane, an action potential

will not occur

Which of the following membrane transporters are present throughout the membrane of a neuron

-Sodium leak channels -Na+/K+ pumps -Potassium leak channels

Place the events of EPSP In order

1. The excitatory Neurotransmitter binds to the chemically gated cat ion channel 2. More Na+ enters the postsynaptic cell then k+ leaves 3. The inside of the cell becomes more positive 4. The local current of NA+ becomes weaker as it moves towards the axon hillock

If acetylcholinesterase became mutated and nonfunctional, what would be the immediate result?

Acetylcholine would build up in the synaptic cleft.

Action potentials are always propagated along an axon at the same______ but ____ can vary depending on the strength of the frequency

Amplitude; frequency

At the synaptic knob, voltage-gated________ channels open, thereby stimulating the synaptic vesicles to release their neurotransmitters by exocytosis

Calcium

The presence of _________ions cause the synaptic vessels a bind to the membrane allowing Neurotransmitters to be released

Calcium

resting membrane potential of -70 mV indicates that the_______.

Charges lining the inside of the plasma membrane are negative compared to the charges lining the outside.

Which of the following are characteristics of neurons

Conductivity amitotic secretions excitability extreme longevity

The electrical gradient in a resting neuron it's such that the_______ of the cell is negative relative to the_________.

Inside Outside

Repolarization is due to the opening of voltage-gated ________ And the subsequent movement of the _________ out of the cell

K+, K+

anterograde axonal transport

Movement of nutrients in a neuron away from the cell body distally to axon termination

retrograde axonal transport

Movement of used or worn out materials from distal areas to cell body

Many excitatory neurotransmitters caused the opening of channels that allow for the flow of

Na+ and k+

Which of the following pumps can you find in the plasma membrane?

Na+, K+, Ca2+

Voltage is a measure of relative_______ energy

Potential

Graded potentials are produced within the _____ segment or a neuron.

Receptive

Flow of the __________ ion is the most common cause of depolarization

Sodium

The two factors that affect PNS regeneration are

The amount of damage and the distance between injury and the effector organ

The myelin sheath covers_______.

The axon

If demyelination occurs, why don't action potentials occur at regions of the axon that were previously myelinated?

These regions lack the appropriate concentration of voltage-gated sodium channels.

In retrograde transport, substances are moved______ the cell body

Toward

A synapse is a junction between

a neuron and another cell

The nerve impulse causes _______ in the number of calcium ions that enter the synaptic knob

an increase

Which glial cell occupies the space of dying neurons

astrocytes

Cytoplasm within an axon is called

axoplasm

The central nervous system is made up of the

brain and spinal cord

components of the central nervous system

brain and spinal cord

Most synapses in the Human body are

chemical synapses

The total length of the axon is called the ______ segment

conductive

The main activity of the ______ is the propagation of an action potential along the axolemma.

conductive segment

demyelinating diseases cause a ______ And the conduction velocity of action potentials.

decrease

A positive change in the membrane potential is called

depolarization

Glial cells _____ transmit electrical impulses

do not

Creating and transmitting ___________ currents is central to the function of neuron physiology

electrical

A difference in the number of charged particles between two sides of the membrane forms a

electrical gradient

______ is responsiveness to stimuli.

excitability

Action potentials occur

in the unmyelinated regions of an axon

When voltage-gated sodium channels are open, sodium flows _____________ the neuron making the inside of the cell more _______________.

into; positive

graded potentials result from the opening of

ligand-gated channels

A myelin sheath is made of a high percentage of

lipids

If a neuron has many dendrites and a single axon, it is called a(n) ______ neuron.

multipolar

Most motor neurons are

multipolar

The presence of a ______ sheath increases the rate of impulse conduction.

myelin

A cablelike bundle of axons in the peripheral nervous system is called a ______.

nerve

What is the primary tissue of the nervous system?

nervous tissue

Nervous tissue is composed of glial cells and

neurons

The functions of astrocytes are to

- help form the blood-brain barrier - assist neuronal development - regulate the composition of the interstitial fluid