The Nervous System

Question 1

Outline the nervous system

Answer 1

• A network of nerve cells that carry messages to and from the brain and spinal cord to different parts of the body
• Coordinates the behaviour of the body.

Question 2

What are the main functions of the nervous system?

Answer 2

• Collect, process and respond to sensory information in the environment
• Coordinate workings of different cells and organs in the body

Question 3

What are the two sub-systems that the nervous system divided is into?

Answer 3

• The central nervous system (CNS), then brain and spinal cord
• Peripheral nervous system

Question 4

Outline the central nervous system

Answer 4

Made up of the brain and spinal cord and has two main functions:
- Control of behaviour and regulation of the body’s physiological processes
- To do this, brain must receive information from the sensory receptors and send messages to the muscles and glands.
- Involves the spinal cord, collection of nerve cells attached to brain and run the length of the spinal column

Question 5

Describe the functions of the spinal cord in the CNS

Answer 5

• Relay information between the brain and the rest of the body. Allows brain to monitor bodily processes and coordinate voluntary movements
• Connected with specific muscles and glands and connects nerves to the PNS
• Responsible for simple reflexes, without direct involvement e.g. pulling away from a hot pan.

Question 6

What happens if the spinal cord is damaged?

Answer 6

Areas supplied by spinal nerves below the damaged site will be cut off from the brain and will stop functioning

Question 7

Outline the peripheral nervous system (PNS)

Answer 7

• All the nerves outside of the CNS make up the PNS.
• It relays nerves impulses from the CNS to the rest of the body back to the CNS

Question 8

What are the two main divisions of the peripheral nervous system?

Answer 8

• Somatic nervous system
• Autonomic nervous system

Question 9

Describe the somatic nervous system

Answer 9

• Made up 12 pairs of cranial nerves (emerge directly from the underside of the brain) and 31 pairs of spinal nerves (emerge from the spinal cord)
• These nerves have both sensory and motor neurons. Sensory relay messages to the CNS, motor relay information from the CNS to other areas of the body.
• This system controls muscle movement, involved in reflex actions without involvement of the CNS so it can occur very quickly

Question 10

Describe the autonomic nervous system

Answer 10

• Governs vital functions like breathing, heart rate and digestion.
• These involuntary actions are regulated by the ANS, and it’s autonomous

Question 11

What are the two further divisions of the autonomic. nervous system?

Answer 11

• Sympathetic nervous system
• Parasympathetic nervous system

Question 12

Describe the sympathetic nervous system

Answer 12

• Represents a state of physiological arousal (breathing gets faster, heart beat rapidly etc.)
• Prepares the body for ‘fight or flight’ response a means of coping with stress.

Question 13

Describe the parasympathetic nervous system

Answer 13

• Contradicts the SNS, produces the opposite effects.
• The ‘rest and digest’ response returns the body to normal resting state after the threat of stress has passed

Question 14

Outline all the things that the sympathetic state causes in the body

Answer 14

• Increases heart/breathing rate
• Dilates pupils
• Inhibits digestion/saliva production
• Contracts rectum

Question 15

Outline all the things that the parasympathetic state causes in the body

Answer 15

• Decreases heart/breathing rate
• Constricts pupils
• Stimulates digestion/saliva production
• Refixes rectum

Question 16

Describe how the body would respond to a threat (involving all system)

Answer 16

• Brain receives threat message then sends signals down to the spine
• Spine sends signals to the sympathetic nervous system which prepares the flight of fight response