B3.1 The Nervous System

Which definition would be the best description of a stimulus?

• A. A detectable change in the internal or external environment of an organism

• B. A gap between two neurones

• C. A signal which is passed through the nervous system as electrical charge

• D. A nerve pathway which triggers an automatic response

The image below shows a sensory neurone which forms part of a reflex arc in the nervous system. An impulse moves along the neurone from Q to P. What structures would be found at P?

• A. An effector

• B. A motor neurone

• C. A synapse

• D. A relay neurone

A motor neurone is usually stimulated by a relay neurone. Which part of the motor neurone is first stimulated by a relay neurone?

• A

• B

• C

• D

The diagram shows a reflex arc. A patient needs treatment for a leg injury. An anaesthetic is injected to block nerve impulses to prevent pain but still allow movement of the leg. Where was the anaesthetic injected in this patient?

• At X

• At Y

• At Z

• At X, Y, and Z

Which label is pointing to the myelin sheath in a sensory neurone?

• A

• B

• C

• D

What is the name of the gap between two neurones?

• Axon

• Dendrite

• Lumen

• Synapse

What component of the nervous system is responsible for transmitting information from the brain to various parts of the body?

• A. Central Nervous System

• B. Peripheral Nervous System

• C. Autonomic Nervous System

• D. Somatic Nervous System

In a typical reflex arc, which type of neurone transmits signals from a sensory receptor to the spinal cord?

• A. Motor neurone

• B. Sensory neurone

• C. Interneurone

• D. Relay neurone

Name the two organs of the Central Nervous System (CNS)

Answer explanation

Brain

Spinal Cord

Neurones carry __________ in the form of __________ called ____________.