GRQ #6 - ANS and Reflexes

Question 1

What are some examples of vital functions that the autonomic nervous system oversees?

Answer 1

heart rate, blood pressure, digestive and urinary processes

Question 2

The ANS operates ____.

Answer 2

autonomously or without conscious control

Question 3

What is a visceral reflex arc?

Answer 3

A series of events in which a sensory stimulus in an organ leads to a predictable visceral motor response mediated by the ANS

Question 4

How does the ANS perform many of its autonomous functions?

Answer 4

through a series of visceral reflex arcs

Question 5

How many steps occur in a visceral reflex arc of the ANS? (according to figure 14.1)

Answer 5

4

Question 6

What is step 1 of a visceral reflex arc of the ANS?

Answer 6

1. sensory signals from the viscera and skin are sent by afferent sensory neurons to the brain or to the spinal cord

Question 7

What is step 2 of a visceral reflex arc in the ANS?

Answer 7

2. the stimuli are then integrated by the CNS

Question 8

What is step 3 of a visceral reflex arc in the ANS?

Answer 8

3. motor impulses from the CNS are sent out via efferent motor neurons in cranial and spinal nerves that usually lead to autonomic ganglia (ganglia in the PNS)

Question 9

What is step 4 of a visceral reflex arc in the ANS?

Answer 9

4. the autonomic ganglia send the impulses via other efferent motor neurons to various target organs, where they trigger a motor response in the target cells

Question 10

What are autonomic ganglia?

Answer 10

A collection of cell bodies of postganglionic autonomic neurons

Question 11

Somatic motor neurons largely control what type of movement? They innervate what kind of muscle fibers?

Answer 11

Voluntary muscle contractions or those that are initiated consciously. Somatic motor neurons innervate skeletal muscle fibers.

Question 12

How do somatic motor neurons stimulate skeletal muscle fibers?

Answer 12

They stimulate skeletal muscle fibers by releasing the neurotransmitter acetylcholine (ACh)

Question 13

The somatic nervous system targets ____ and controls ___ movement.

Answer 13

skeletal muscle fibers; voluntary

Question 14

The autonomic nervous system targets ____, ____, and ____ and controls ____ movement.

Answer 14

smooth muscle cells, cardiac muscle cells and glands; involuntary

Question 15

Motor neurons in the autonomic nervous system ___ directly innervate their target cells. Instead ___ ___ are involved.

Answer 15

Do NOT. Instead 2 neurons are involved.

Question 16

What are the names of the 2 neurons involved in innervating target cells in the ANS?

Answer 16

The preganglionic neuron and the postganglionic neuron.

Question 17

What is the preganglionic neuron?

Answer 17

The initial efferent autonomic neuron whose cell body is located in the CNS in either the spinal cord or the brainstem.

Question 18

Where does the preganglionic neuron synapse?

Answer 18

On the cell body of the postganglionic neuron within an autonomic ganglion in the PNS.

Question 19

What is the postganglionic neuron?

Answer 19

An autonomic neuron whose cell body is located in an autonomic ganglion in the PNS.

Question 20

Where does the axon of the postganglionic neuron synapse?

Answer 20

On the target cell

Question 21

How does the postganglionic neuron trigger a change?

Answer 21

It triggers a change by releasing various neurotransmitters, including ACh and norepinephrine.

Question 22

The neurotransmitters released by the postganglionic neuron may ___ or ____ their target cell.

Answer 22

stimulate or inhibit.