bio chapter 12

To perform their role, neurons must have the properties of excitability, secretion and. A. Contractility B. Extensibility C. Elasticity D. Conductivity E. Stretchiness

Conductivity

Neurons receive incoming signals by way of specialized extensions of the cell called. A. Axons B. Somas C. Collateral axons D. Trigger zones E. Dendrites

dendrites

This statement best describes the myelin sheath. A. Made of schwann cells B. Covering surrounding an axon C. Provides insulation from other axons D. Helps conduct The action potential more rapidly E. All true

All true

This best describes the refractory period. A. Limits how many action potentials can be produced during a given period of time. B. Prevents an action potential from starting another action potential at the same point on the plasma membrane C. Is the period of time when a strong stimulus can initiate a second action pontential D. Both a and b E. All the above

Both a and b

These cell types produce and help circulate cerebrospinal fluid. A. Astrocytes B. Microglia C. Ependymal cells D. Schwann cells E. Oligodendroctes

Ependymal cells

In the Cns myelin is produced by glial cells called schwann cells. True or False

False

Neurons that convey information to the CNS are called sensory. or efferent, neurons. True or False

False

The resting membrane potential of nerve cells due to the electric charge difference across the plasma membranes is approximately -85mv True or False

False

An inhibitory postsynaptic potential is ____ of the postsynaptic neuron. A. A refractory period B. An action potential C. A depolarization D. A repolarization E. Hyperpolarization

Hyperpolarization

Saltatory conduction occurs only. A. At chemical synapses B. In the initial segment of an axon C. In both the initial segment of an axon and axon hillock D. In myelinated nerve fibers E. IN unmyelinated never fibers

In myelinated nerve fibers

These cells conduct action potentials from one neuron to another within the CNS. A. Sensory B. Motor C. Interneurons D. Bipolar neurons

Interneurons

These statements about unipolar neurons are all true except. A. Most are sensory neurons B. have a single process extending from the cell body C. Located in the eye and nasal cavity D. Are a type of structural neuron

Located in the eye and nasal cavity

The glial cells that fight infections in the CNS are. A. Microglia B. satellite cells C. Ependymal cells D. Oligodendrocytes E. Astrocytes

Microglia

Because of the sodium-potassium pump, there are.

More K+ inside the cell that outside and more Na+ outside the cell than inside

The highest density of voltage gated ion channels is found on the ____ of a myelinated neuron. A. dendrites B. Soma C. Nodes of ranvier D. Internodes E. Axon terminals

Nodes of ranvier

During saltatory conduction action potentials jump from this. A. One astrocyte to another B. An axon to a dendrite C. One internode to another D. One node of ranvier to another E. One microglia to another

One node ranvier to another

Some neurotransmitters can be either excitatory or inhibitory depending on the type of. A. Receptors on the postsynaptic cell B. Synaptic vesicles in the axon C. Synaptic potentiation that occurs D. Postsynaptic potentials on the axon terminal E. Neuromodulator involved

Receptor on the postsynaptic cell

This portion of the motor division of the nervous system conducts action potentials from the central nervous system to skeletal muscle fibers. A. Afferent B. Autonomic C. Somatic D. Sympathetic

Somatic

This is NOT a part of the peripheral nervous system A. Cranial nerve B. Ganglion C. Spinal cord D. Spinal nerve

Spinal cord

The following are characteristics of an action potentials except. A. All or none B. Caused by graded potentials reaching threshold C. Stimulus strength determines the magnitude D. Depolarization is followed by repolarization

Stimulus strength determines the magnitude

A myelinated nerve fiber can produce action potentials only in specialized regions called nodes of ranvier. True or False

True

The absolute refractory period is a period of time in which a neuron is producing an action potential and cannot respond to another stimulus of any strength. True or False

True

Compared to the outside of the resting cell membrane the inside surface of the membrane us this. A. Positively charged B. Electrically neutral C. Negatively charged D. Continuously reversing so that it is positive one second and negative the next

negatively charged