The Mammalian Nervous System

Question 1

Define the autonomic nervous system.

Answer 1

Part of the nervous system responsible for controlling the involuntary motor activities of the body.

Question 2

What is the central nervous system?

Answer 2

The central part of the nervous system composed of the brain and spinal cord.

Question 3

What is the peripheral nervous system?

Answer 3

The sensory and motor nerves connecting the sensory receptors and effectors to the CNS.

Question 4

What is the somatic nervous system?

Answer 4

The motor neurones under conscious control

Question 5

What must the communication system enable?

Answer 5

Detection of changes in the environment.
Cell signalling to occur between all parts of the body.
Coordination of a range of effectors to carry out responses to sensory input.
Suitable responses.

Question 6

What does the PNS split into?

Answer 6

The sensory system and the motor system.

Question 7

What does the motor system split into?

Answer 7

The somatic nervous system and the autonomic nervous system.

Question 8

What do the myelinated neurones making up the white matter do in the spinal cord?

Answer 8

They carry action potentials up and down the spinal cord for rapid communication over long distances.

Question 9

What is the role of the PNS?

Answer 9

To ensure rapid communication between the sensory receptors, the CNS and the effectors.

Question 10

Describe the structure of the sensory nervous system.

Answer 10

The sensory fibres entering the CNS are dendrons of the sensory neurones. These neurones conduct action potentials from the sensory receptors into the CNS. These neurones have their cell body in the dorsal root leading into the spinal cord and a short axon connecting to other neurones in the CNS.

Question 11

What is the role of the motor nervous system?

Answer 11

Conducts action potentials from the CNS to the effectors.

Question 12

What does the somatic nervous system consist of?

Answer 12

Motor neurones that conduct action potentials from the CNS to the effectors that are under voluntary (conscious) control, such as the skeletal muscles.
There is always one single motor neurone connecting the CNS to the effector.

Question 13

Are the neurones of the SNS myelinated?

Answer 13

Yes, so that the response can be rapid.

Question 14

What does the ANS consist of?

Answer 14

Motor neurones that conduct action potentials from the CNS to effectors that are not under voluntary control.

Question 15

What does the ANS include?

Answer 15

This includes the glands, the cardiac muscle and smooth muscle in the walls of the blood vessels, the airways and the wall of the digestive system.

Question 16

Why are most of the neurones in the ANS non-myelinated?

Answer 16

The control of the effectors do not require rapid responses.

Question 17

How are the two neurones involved in the connection between the CNS and the effector connected?

Answer 17

By small swellings called ganglia.

Question 18

What is the ANS responsible for controlling?

Answer 18

The majority of the homeostatic mechanisms and play a vital role in maintenance of the environment of the body.

Question 19

What can the autonomic nervous system be further broken down into?

Answer 19

The sympathetic nervous system and the parasympathetic nervous system.

Question 20

What does the sympathetic nervous system do?

Answer 20

Prepares the body for activity.

Question 21

What does the parasympathetic nervous system do?

Answer 21

Conserves energy.

Question 22

How are the sympathetic/parasympathetic an antagonistic relationship?

Answer 22

As the action of one system opposes the action of the other.

Question 23

What are the effects of the sympathetic nervous system?

Answer 23

Increased heart rate
Dilated pupils
Increased ventilation rate
Reduced digestive activity
Orgasm

Question 24

What are the effects of the parasympathetic nervous system?

Answer 24

Decreased heart rate
Constriction of pupils
Reduced ventilation rate
Increased digestive activity
Sexual arousal