Question 1: Define the term 'reflex arc'.

Answer: A reflex arc is a neural pathway that mediates a reflex action, allowing an immediate response without conscious brain involvement.

Question 2: List the main components of a reflex arc in the correct order.

Answer: Receptor, sensory neuron, relay neuron (interneuron), motor neuron, effector.

Question 3: Explain how a reflex action differs from a voluntary action.

Answer: A reflex action is rapid, automatic, and does not involve conscious thought, whereas voluntary actions are controlled by the brain and involve conscious decision-making.

Question 4: Identify the type of neuron responsible for transmitting signals from the receptor to the relay neuron.

Answer:

Question 5: Fill in the blank: During a reflex action, the signal bypasses the _______ in the brain, allowing for a faster response.

Answer: cerebral cortex

Question 6: Describe the role of the spinal cord in a reflex arc.

Answer: The spinal cord acts as the processing centre that receives sensory information and immediately sends out motor commands to the effector, enabling rapid responses.

Question 7: Calculate the total time taken for a reflex action if the sensory signal takes 0.02 seconds, the relay within the spinal cord takes 0.01 seconds, and the response at the effector takes 0.03 seconds.

Answer: Total time = 0.02 + 0.01 + 0.03 = 0.06 seconds

Question 8: Identify a practical scenario where a reflex arc is crucial for safety.

Answer: When touching a hot surface, the reflex arc causes immediate withdrawal of the hand to prevent burns.

Question 9: Propose a simple experiment to demonstrate the reflex action of the knee-jerk reflex.

Answer: In a controlled setting, tap the patellar tendon below the kneecap with a reflex hammer while the subject is seated. Observe the involuntary extension of the lower leg, demonstrating the reflex arc involving the spinal cord.

Question 10: Explain how understanding the reflex arc can aid in diagnosing neurological conditions.

Answer: By testing reflex responses, healthcare professionals can identify nerve damage or neurological disorders, as abnormal or absent reflexes may indicate underlying issues.

Question 11: Discuss how technological advancements have enhanced our understanding of the reflex arc.

Answer: Techniques like electrophysiology and neuroimaging allow detailed study of nerve pathways and response times, leading to better diagnosis and understanding of neural functions related to reflexes.