Chapter 11 nervous system

Which of the following statements correctly characterizes an action potential?

Action potentials are initiated by depolarization of the membrane to threshold.

Each of the following statements correctly describes an action potential EXCEPT which one?

Action potentials are propagated by the sodium-potassium pump.

How is an action potential propagated along an axon?

An influx of sodium ions from the current action potential depolarizes the adjacent area.

Why are many muscles at the effector end of the reflex arc found in antagonistic pairs?

Antagonistic muscles have opposite actions. This is often needed for a reflex.

Control of smooth muscle and internal organs is the role of the ________ division of the nervous system?

Autonomic

During synaptic transmission, the influx of ________ causes vesicles in the axon bulb to fuse with the cell membrane, releasing ________.

Ca2+, neurotransmitter

Which part of the brain is associated with conscious thought, memory, and personality?

Cerebral cortex

A nerve impulse moves toward a neuron's cell body along _____.

Dendrites

An action potential is a long or rapid release of energy, generated by the sodium-potassium pumps of neurons.

False

True or false. An individual who has suffered a stroke, which has caused damage in his cerebrum, and is now having problems with his hearing, has probably suffered damage to his occipital lobe.

False

What type of cell makes up the myelin sheath of a motor neuron?

Schwann cells

transmit impulses toward the central nervous system

Sensory neurons

1. Using energy from ATP, __________ actively transport ions in both directions across the membrane.

Sodium-potassium pumps

Which part of the brain functions as a relay station for information to the limbic system and the cerebral cortex?

Thalamus

Why does the action potential only move away from the cell body?

The areas that have had the action potential are refractory to a new action potential.

Which of the following does NOT apply to the peripheral nervous system (PNS)?

The somatic division controls smooth muscle activity.

Motor neurons of the peripheral nervous system transmit impulses away from the central nervous system.

True

The velocity of the action potential is fastest in which of the following axons?

a small myelinated axon

Which set of words can correctly be used to describe interneurons?

excitatory and inhibitory

Transmit impulses within the central nervous system

interneurons

Transmit impulses away from the central nervous system

motor neurons

Axons insulated by a(n) _____ are able to conduct impulses faster that those not so insulated.

myelin sheath

An impulse relayed along a myelinated axon "jumps" from _____ to _____.

node of Ranvier ... node of Ranvier

Which one of the following divisions of the nervous system predominates during the relaxed state?

parasympathetic division

Some __________ are open, allowing certain ions to move out of the cell through them

potassium channels

The concentration of _________ is higher inside of the cell than outside

potassium ions

A neuron at rest has a charge difference across its cell membrane, with the interior of the cell negative relative to the exterior. This difference in charge across the plasma membrane is referred to as ________ potential

resting

Which one of the following provides the central nervous system with information about the outside environment?

sensory division

You touch a hot stove and your hand quickly jerks away. What is the path of the nerve impulses that are responsible for this reflex?

sensory neuron to interneuron to motor neuron

Which component of a reflex arc carries information to the central nervous system?

sensory neurons

The ________ are closed, preventing certain ions from entering the cell through them

sodium channels

The concentration of __________ is higher outside of the cell than inside

sodium ions

Which of the following would cause an acceleration of heart rate, an increase in blood pressure, and a slowing of digestive processes?

sympathetic division of the autonomic nervous system

What part of a neuron relays signals from one neuron to another neuron or to an effector?

synaptic terminal

A spinal reflex requires the participation of each of the following, EXCEPT __________.

the cerebral cortex

What is the difference between a reflex and a reflex arc?

A reflex is an automatic response; a reflex arc is the neural circuitry.

A nerve impulse moves away from a neuron's cell body along _____.

Axons

A neuron's nucleus is located in its _____.

Cell body