Quiz 5 Basic Nervous System

On a particular patch of axolemma, the electrical events that occur as an action potential travels by can be ordered as Depolarization Repolarization Hyperpolarization

1,2,3

Events of Axon Regeneration in order Axon regenerates and myelination occurs. The skeletal muscle becomes re-innervated by the axon. Glial cells that myelinate the axon form a regeneration tube. Peripheral nerve injury results in the severing of an axon. The proximal part of the axon seals off and swells; the distal part degenerates.

4,5,3,1,2

Ganglia and clusters of neuron cell bodies are located within the CNS T/F

False

Glial cells help neurons by generating action potentials. T/F

False

In neurons, protein pumps allow substances to move passively down their concentration gradients.

False

The endoneurium wraps around groups of fascicles to form a nerve. T/F

False

What type of cells produce the myelin sheath in the central nervous system (CNS)?

Oligodendrocytes

Scorpion agitoxin is a neurotoxin that blocks the activity of voltage-gated potassium channels. In the presence of agitoxin, which will occur during an action potential?

The neuron will remain depolarized and unable to repolarize.

Fast retrograde transport returns used synaptic vesicles and other materials to the soma and informs the soma of conditions at the axon terminals. T/F

True

Sodium has a higher concentration outside the cell than within.

True

The _______ is a period when a membrane cannot respond to another stimulus (no matter how strong).

absolute refractory period

The time when there is complete insensitivity of the plasma membrane to another stimulus

absolute refractory period

Consists of the brain and spinal cord

central nervous system

When a neurotransmitter binds a protein channel, it opens and lets sodium diffuse down its concentration gradient. This is an example of a

chemically gated sodium channel.

Decrease in the membrane potential

depolarization

Inside of the cell becomes more positive

depolarization

a decrease in the extracellular concentration of potassium

depolarization

an increase in the number of sodium leak channels

depolarization

An increase in the extracellular concentration of potassium

hyperpolarization

Increase in the membrane potential

hyperpolarization

the inside of the cell becomes more negative

hyperpolarization

Includes cranial nerves, spinal nerves, and ganglia

peripheral nervous system

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

positive

A time when there is a decrease in the sensitivity of the plasma membrane to further stimulation.

refractory period

The time when a stronger-than-threshold stimulus is needed to initiate another action potential

relative refractory period

The ___________ nervous system transmits information from receptors to the CNS, while the ___________ nervous system transmits information from the CNS to the rest of the body.

sensory;motor

The fundamental physiological properties that enable nerve cells to communicate with other cells are

the ability to respond to environmental changes. the ability to produce electrical signals that are quickly conducted to other cells at distant locations. the ability to secrete a chemical that will stimulate the next cell when an electrical signal reaches the end of an axon.

The negative value of the resting membrane potential means that

there are more negatively charged particles on the inside of the membrane than on the outside.