Reflex Arcs

The diagram represents a simple reflex arc.

What is the sequence of nerve cells through which an impulse passes during a reflex action?

• A

• B

• C

• D

The diagram shows a neurone.

• A

• B

• C

• D

Tags

NGSS.MS-LS1-3

Which diagram shows a sensory neurone?

• A

• B

• C

• D

Tags

NGSS.MS-LS1-3

Which responses occur when a person is too hot?

• A

• B

• C

• D

A boy accidentally touches a very hot object and immediately takes his hand away. In this reflex action, what is the effector?

• a heat receptor in his hand

• a motor neurone

• a muscle in his arm

• the spinal cord

A man injures his arm in an accident. Afterwards, he can feel objects touching his hand, but he cannot move his hand away from them.

What could cause this?

• Receptors in his hand are damaged.

• The nerve connection is cut only between the receptors in his hand and his central nervous system.

• The nerve connection is cut only between his central nervous system and the effectors in his arm.

• Both of these nerve connections are cut.