The Nervous System

Question 1

What is the Nervous System?

Answer 1

• Made up of billions of nerve cells working together.
• Primary internal communication system.
• Two primary tasks:
  1. To gather, transform and respond to environmental information.
  2. To ensure that the functions of the organs and cells are synchronised.
• Comprises the central and peripheral nervous systems.

Question 2

What is the Central Nervous System?

Answer 2

• Made up of the brain and the spinal cord.
• Two main functions:
  1. Control of Behaviour.
  2. Regulation of the body’s physiological processes.
• Brain must be able to receive information from sensory receptors and send messages to the muscles and glands of the body - involves the spinal cord, a collection of nerves cells attached to the brain and run the length of the spinal column.

Question 3

The Brain

Answer 3

• Centre of all conscious awareness.
• Outer layer, cerebral cortex, is highly developed in humans and what distinguishes our higher mental functions from those of animals.
• Can be divided into 4 main areas - cerebral cortex, cerebellum, diencephalon and brain stem.

Question 4

The Spinal Cord

Answer 4

• An extension of the brain.
• Long bundle of nerve cells that carry messages to and from the body to the brain and is responsible for very fast, life saving reflexes.
• Passes messages between the brain and the rest of the body.
• Connected to different parts of the body by pairs of spinal nerves which connect with specific muscles and glands.
• Contains a circuit of nerve cells that enable us to perform reflexes without the brain.
• If it is damaged, areas of the spinal nerves below the damaged site will cut off from the brain and stop functioning.

Question 5

What is the Peripheral Nervous System?

Answer 5

• Refers to any nerves and nerve cells which are not a part of the brain or spinal cord.
• Send information via millions of neurons to the CNS from the environment and relay messages from the CNS to glands and muscles.
• Two divisions:
  1. Somatic Nervous System
  2. Autonomic Nervous System.

Question 6

The Somatic Nervous System

Answer 6

• Made up of 12 pairs of cranial nerves and 31 pairs of spinal nerves.
• Nerves have both sensory neurons and motor neurons.
• Sensory neurons relay messages to CNS.
• Motor neurons really information from the CNS to other parts of the body.
• Controls voluntary muscle movements.
• Receives information from sensory receptors.
• Somatic system is involved in reflex actions which allows the reflex to occur very quickly.

Question 7

The Autonomic Nervous System

Answer 7

• Responsible for involuntary movements.
• Communicates information to and from our organs.
• Split into two branches:
  1. Sympathetic Nervous System
  2. Parasympatheic Nervous System
• Both tend to regulate same organs but have opposite effects. Due to neurotransmitters associated with each division.

Question 8

The Sympathetic Nervous System

Answer 8

• Involved in responses that help us to deal with emergencies. (Fight of Flight).
• Neurons travel from SNS to every organ and gland within the body, preparing the body for rapid action when an individual is under threat.
• Causes the body to release stored energy, pupils dilate, slows down less important bodily processes during emergencies such as digestion.

Question 9

The Parasympathetic Nervous System

Answer 9

• Restores the body back to normal functioning after emergency has passed.
• Slows down heart rate and blood pressure down.
• Digestion begins again.
• Sometimes known as the rest and digest system.