7.3 Divisions of the Nervous System

Question 1

How does the CNS coordinate appropriate responses?

Answer 1

The CNS integrated the information it receives from the sensory receptors in different body parts to coordinate appropriate responses.

Question 2

What is included in the CNS?

Answer 2

The brain and the spinal cord; the brain is continuous with the spinal cord.

Question 3

How are the brain and the spinal cord protected?

Answer 3

The brain is enclosed by the skull; the spinal cord is enclosed by the vertebral column.

Question 4

What’s one of the function of the spinal cord?

Answer 4

The spinal cord connects the brain to different body parts through many nerves.

Question 5

What are the reflexes that the spinal cord meditates?

Answer 5

They are automatic and almost instantaneous behavioural responses to a particular stimuli.

Question 6

What is in control of the whole body?

Answer 6

brain is the control center of the body.

Question 7

What is one of the functions of the brain?

Answer 7

It coordinates bodily activities by interpreting sensory signals received from different parts of the body and then activating effectors.

Question 8

What are other important bodily processes is the brain responsible for?

Answer 8

Body movements, memory speech, and regulation of body temperature, heart rate, and breathing rate.

Question 9

What does the PNS consist of?

Answer 9

Nerves and receptors located outside the CNS. (the PNS connects the CNS to different body parts).

Question 10

What do nerves include?

Answer 10

Motor and/or sensory axons.

Question 11

What do the spinal nerves do?

Answer 11

Each pair of spinal nerves transmit information between the spinal cord and a particular part of the body.

Question 12

How many pairs of spinal nerves do human have?

Answer 12

31 pairs pairs of spinal nerves extending from the spinal cord to different body parts.

Question 13

How many pairs of carnival nerves do humans have? And what are they?

Answer 13

12 pairs of carina nerves that extend directly from the brain, each to a particular region of the body.

Question 14

What are the 2 branched that the peripheral nervous system divided into?

Answer 14

One branch is associated with voluntary actions; the other is associated with involuntary actions.

Question 15

What is a voluntary action?

Answer 15

It’s an action that you deliberately decide to do. It is an action in which a conscious choice is made, even if it is a response to a stimulus.

Question 16

What is an involuntary action?

Answer 16

it is an action that happens automatically, without conscious awareness or control.

Question 17

List some examples of involuntary actions.

Answer 17

peristaltic movements in the esophagus, constriction or dilation of blood capillaries, heartbeat, and reflexes.

Question 18

List an example of voluntary action.

Answer 18

For example, you hear the telephone ringing and you decide to answer. This action is a voluntary action because it’s under your control; you could choose not to answer the phone. The decision to answer (or not answer) the telephone originates in the brain, which also coordinates all the complex muscle movements involved in standing up, walking across the room, picking up the telephone, holding it up to your ear, and saying “hello”.

Question 19

Define a reflex.

Answer 19

a very rapid response to a particular stimulus, and usually its function helps prevent damage to the body.

Question 20

Is any thought required in a reflex?

Answer 20

No, no thought or processing time is involved in a reflex action; it’s an automatic reaction.

Question 21

Give an example of a reflex.

Answer 21

The rapid withdrawal of the hand upon touching a hot or a sharp object.

Question 22

What happens when a hot object is encountered?

Answer 22

When a hot object is encountered, sensory receptors in the skin send a nerve impulse along the axon of a sensory neuron to the nearest region of the CNS, which in this example is in the spinal cord. Once inside the spinal cord, the sensory neuron passes the nerve impulse to several relay neurons that form the synapses with the motor neurons. The nerve impulse transmitted by the relay neurons is carried down the motor neuron axon from the spinal cord to the effector muscles.

Question 23

What does the impulse do to muscles?

Answer 23

Causes some muscles groups in the hand to contract and causes others to relax so that the hand is withdrawn from the source of the stimulus.

Question 24

Was there any time wasted in processing or thinking about the sensory information?

Answer 24

No, no time wasted, so the hand is removes as quickly as possible to reduce or avoid the burning of tissues. The brain is informed of this action after the hand has been removed from the danger.

Question 25

What is the reflex arc?

Answer 25

In a reflex action, the pathway taken by the nerve impulse form the receptor top the effector is called the reflex arc.

Question 26

How many neurons were involved in the hand withdrawal reflex?

Answer 26

Several neurons. Some reflexes involve only a motor neuron and a sensory neuron- the sensory neuron synapses directly with the motor neuron.

Question 27

Give an example of the motor-sensory neuron reflex.

Answer 27

Knee jerk reflex, in which a small tap under the kneecap causes the lower leg to rise, or jump.

Question 28

What path does the reflex arc take?

Answer 28

Follows the shorts path to the nearest CNS; thus, it may involve either the brain or teh spinal cord.

Question 29

What type of neurons are involved in reflexes above the neck?

Answer 29

Reflexes involving organs above the neck usually involve neurons in the brain.

Question 30

Give an example of neurons involving the brain.

Answer 30

Eye blink is a cranial reflex (occurs via the brain); however this doesn’t mean that thinking is involved.

Question 31

All reflexes are automatic, list some of these examples.

Answer 31

Whether spinal or cranial.