Reflex action and the reflex arc — practice questions

Question 1 · difficulty L1 · recall

The neural pathway mediating a reflex:

• A. endocrine axis
• B. motor unit only
• C. portal system
• D. reflex arc

Question 2 · difficulty L1 · recall

What is a reflex action?

• A. A slow consciously planned movement
• B. A rapid involuntary response to a stimulus
• C. A permanent receptor change
• D. Only a hormonal response

Question 3 · difficulty L1 · recall

Which component of a reflex arc detects the stimulus?

• A. Motor neuron
• B. Effector
• C. Receptor
• D. Interneuron

Question 4 · difficulty L2 · understanding

Which sequence correctly represents a simple reflex arc?

• A. Motor neuron → receptor → CNS → effector
• B. Effector → motor neuron → receptor → CNS
• C. CNS → receptor → sensory neuron → effector
• D. Receptor → sensory neuron → CNS → motor neuron → effector

Question 5 · difficulty L2 · understanding

Why can withdrawal of a hand from a hot object occur before conscious pain awareness?

• A. The spinal cord can organise the immediate response first
• B. Pain receptors bypass sensory neurons
• C. The brain never receives the signal
• D. Motor neurons detect heat directly

Question 6 · difficulty L3 · application

A person touches a hot surface and withdraws the hand. Which neuron carries the command from the spinal cord to the arm muscle?

• A. Sensory neuron
• B. Motor neuron
• C. Receptor neuron only
• D. Interneuron outside the CNS

Question 7 · difficulty L3 · application

The sensory neuron of a withdrawal reflex is destroyed, but the motor neuron and muscle remain intact. What happens after skin stimulation?

• A. The reflex becomes faster
• B. The muscle contracts normally
• C. The reflex is lost because the signal cannot reach the CNS
• D. The receptor activates the muscle directly

Question 8 · difficulty L3 · application

Where is an interneuron in a typical spinal reflex arc located?

• A. Within the tendon attachment
• B. Inside the receptor
• C. Inside the skeletal muscle
• D. Within the central nervous system

Question 9 · difficulty L4 · analysis

A polysynaptic reflex has intact receptors, sensory neurons and motor neurons, but a key spinal interneuron is damaged. What is most likely?

• A. Reflex integration is impaired
• B. The receptor cannot detect the stimulus
• C. The muscle loses actin and myosin
• D. All conscious sensation disappears

Question 10 · difficulty L5 · analysis

Reflex X has one central synapse, while reflex Y contains several interneurons. Which comparison is most reasonable?

• A. Y is always faster
• B. X has less synaptic delay, while Y allows more complex integration
• C. Both have identical delay
• D. X cannot activate skeletal muscle