All Questions page - 566

The key to signal transmission down the length of an axon is that an influx of Na+ ions at an initial location on the axon membrane triggers an influx of _______ on a _______ of the membrane.

Communication between neurons takes place by means of substances called _______moving across a ________ from a sending cell to a receiving cell.

The brain and spinal cord make up the _______nervous system, while all the nervous tissue outside the _______and _______plus the sensory organs make up the _______ nervous system.

The efferent division of the peripheral nervous system is made up of nerves that carry messages _______ the brain or spinal cord, and it is divided up into a portion that provides voluntary control over skeletal muscles—the _______ nervous system—and a portion that provides involuntary regulation over smooth muscle, cardiac muscle, and glands—the _______ nervous system. The afferent division of the peripheral nervous system is made up of nerves that carry messages _______ the brain or spinal cord.

The cells of the nervous system that carry nervous system messages are called _______, each of which has a variable number of _______ that carry signals toward the cell body, and a single _______ that carries signals away from the cell body.

Given the roles of the various regions of the brain, why is it almost literally true to speak of “higher” brain functions?

The peripheral nervous system (PNS) is made up of:

a. the brain and spinal cord.

b. the brain and cranial nerves.

c. sensory organs and all of the nervous system outside the brain and spinal cord.

d. all of the nervous system inside the CNS plus the sensory organs.

e. all of the above.

It is often said that seeing is believing. Is it reasonable to put this much faith in the human visual system?

A nervous system cell capable of responding to light and sending a message about that light to the brain would be both a ______and ________.

a. glial cell; an interneuron

b. glial cell; a motor neuron

c. sensory neuron; an afferent neuron

d. motor neuron; an afferent neuron

e. motor neuron; an efferent neuron

The text notes that humans have a few hundred different types of smell or “olfactory” receptors while dogs have about 1,000. Given this, dogs have a much greater ability to distinguish one scent from another than people do. Meanwhile, humans have sharper daytime vision than dogs and a greater ability to perceive colors in the portion of the visible light spectrum that runs from green through red. With this in mind, in what ways is a daytime walk around the neighborhood likely to be perceptually different for dogs, compared to humans?

An action potential is possible because:

a. neurons are wrapped in myelin.

b. the CNS and PNS are separate.

c. only the spinal cord has to be involved.

d. there is no charge difference across the outer membranes of resting neurons.

e. there is a charge difference across the outer membranes of resting neurons.

A neurotransmitter:

a. is stored in sending cell vesicles.

b. diffuses across the synaptic cleft.

c. binds with receptors on a receiving cell.

d. can sometimes be taken back up by a sending cell.

e. all of the above.

The autonomic nervous system (select all that apply):

a. carries out voluntary decisions.

b. is part of the central nervous system.

c. carries out involuntary regulation.

d. is divided into sympathetic and parasympathetic divisions.

e. is an efferent system.

In the brain, the site of our higher thought processes is the:

a. cerebellum.

b. cerebrum.

c. thalamus.

d. medulla oblongata.

e. hypothalamus

All sensory receptors ____ and ____.

a. respond to stimulation; transform that stimulation into a neural signal

b. respond to all forms of stimulation except smell; send messages through the spinal cord

c. are located in the spinal cord; send messages through the thalamus

d. are located in the brain; interconnect with neurons

e. respond to neurotransmitter stimulation; turn that stimulation into a neural signal

Several of the senses work by means of:

a. the brain distributing portions of its processing to the spinal cord.

b. the brain analyzing the pattern of input from many sensory receptors.

c. the brain receiving messages from sensory receptors and then sending messages back to them.

d. sensory receptors communicating first with each other, then with the brain.

e. sensory receptors responding to light.

Muscle cells are referred to as muscle _______ because of their unusual _______.

Muscle contraction works through the process of a ______ of two kinds of muscle filaments past each other within a muscle unit known as a______.