Chapter 8 web acitivity

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.

Consider the neurotransmitters. Which statement is generally true?

In general, the neurotransmitter of the sympathetic nervous system is norepinephrine, and the neurotransmitter of the parasympathetic nervous system is acetylcholine.

Which of the following statements is true about the interaction of sympathetic and parasympathetic nerve fibers?

Sympathetic and parasympathetic nerve fibers may innervate the same organs, but they have generally opposite effects.

Regarding the gray matter and the white matter of the spinal cord, which statement is most accurate? The gray matter is myelinated and is composed of cell bodies and dendrites. The white matter is composed of axons. The gray matter is unmyelinated and is composed of cell bodies and dendrites. The white matter is myelinated and is composed of axons The gray matter is myelinated, and this is a characteristic of axons. The white matter is composed of cell bodies and dendrites. The gray matter is unmyelinated and is composed of axons. The white matter is myelinated and is composed of cell bodies and dendrites. The gray matter is unmyelinated, and the white matter is myelinated. However, the myelination really has very little to do with whether the matter is composed of axons, dendrites, or cell bodies.

The gray matter is unmyelinated and is composed of cell bodies and dendrites. The white matter is myelinated and is composed of axons

You just cut yourself. Which statement best explains how the spinal cord is involved? While sensory fibers do take the messages to the spinal cord, and motor fibers take the motor messages from the spinal cord, it is impossible to tell whether the dorsal root or ventral root is used unless we also know the location of the cut. The message goes from the cut via the motor fibers to the ventral root of the spinal cord. The motor response message exits the spinal cord via sensory fibers from the dorsal root. The message goes from the cut via the sensory fibers to the ventral root of the spinal cord. The motor response message exits the spinal cord via the dorsal root. The message goes from the cut via the sensory fibers to the dorsal root of the spinal cord. The motor response message exits the spinal cord via the ventral root. The message goes from the cut via the motor fibers to the dorsal root of the spinal cord. The motor response message exits the spinal cord using sensory fibers via the ventral root.

The message goes from the cut via the sensory fibers to the dorsal root of the spinal cord. The motor response message exits the spinal cord via the ventral root.

When discussing the origins of the sympathetic and parasympathetic divisions of the autonomic nervous system, we can most correctly state that ________.

The parasympathetic nerves arise from the brain and part of the spinal cord, and all of the sympathetic nerves arise from the spinal cord

Which of the following statements most accurately describes the spinal cord? The spinal cord takes motor messages from the brain to the organs of the body, but the spinal cord does not actually act to transport messages to the brain. That is the function of the reflex arc, or the reflex center of the spinal cord. The spinal cord takes messages to and from the brain and functions as a reflex center. The spinal cord takes messages to and from the brain, but the spinal cord is only indirectly involved in reflexes and should not be considered to be the reflex center The spinal cord takes sensory messages to the brain but is not a part of motor communication. The reflex component of the spinal cord acts independently of brain. The spinal cord functions as a reflex center but is not directly involved in communication with the brain.

The spinal cord takes messages to and from the brain and functions as a reflex center.

Which statement most accurately describes the relative physical position of the ganglia of the sympathetic and parasympathetic nervous systems?

The sympathetic ganglia are located in chain-like fashion near the spinal cord. The parasympathetic ganglia are located closer to the target organs.

Think of the heart in the tutorial. Now, picture yourself being chased by a herd of wild elephants. What are the sympathetic and parasympathetic actions on your heart?

The sympathetic nervous system will cause the heart rate to speed up. The parasympathetic nervous system will become somewhat inactive.

Which statement correctly describes the number and functional location of the cranial and spinal nerves? Twelve pairs of cranial nerves (all sensory) function only in the head, and 31 pairs of spinal nerves (both sensory and motor) function in the rest of the body. There are 12 pairs of cranial nerves. Some are sensory, some are motor, and some are sensory and motor. Most function only in the head, but two also function in the body proper. There are 31 pairs of spinal nerves. All have both sensory and motor components, and all function in the body proper There are 12 sensory cranial nerves and 12 motor cranial nerves. Most function only in the head, but two also function in the body proper. There are 31 pairs of spinal nerves. All have both sensory and motor components, and all function in the body proper. Twelve pairs of cranial nerves (all motor) function only in the head, and 31 pairs of spinal nerves (both sensory and motor) function in the rest of the body. There are 31 pairs of cranial nerves. Some are sensory, some are motor, and some are sensory and motor. Most function only in the head, but two also function in the body proper. There are 12 pairs of spinal nerves. All have both sensory and motor components, and all function in the body proper.

There are 12 pairs of cranial nerves. Some are sensory, some are motor, and some are sensory and motor. Most function only in the head, but two also function in the body proper. There are 31 pairs of spinal nerves. All have both sensory and motor components, and all function in the body proper.

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

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

Which set of words can correctly be used to describe interneurons? inhibitory and sensory sensory and motor excitatory and motor excitatory and inhibitory

excitatory and inhibitory

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

Complete this sentence. The CNS communicates with the body proper through ________.

the cranial nerves and the spinal nerves