Question 1: Define a reflex arc and explain its role in the nervous system.

Answer: A reflex arc is a neural pathway that mediates a reflex action, allowing for rapid responses without conscious brain involvement to protect the body from harm.

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: Describe how a reflex action differs from a voluntary action.

Answer: A reflex action is an automatic, rapid response that does not involve conscious thought, whereas voluntary actions are deliberate and involve the brain's conscious decision.

Question 1: A reflex response time measured from stimulus to muscle contraction is 0.25 seconds. If the distance from the stimulus to the spinal cord is 1 meter, calculate the average speed of nerve impulse transmission in meters per second (m/s).

Answer: Speed = Distance / Time = 1 meter / 0.25 seconds = 4 m/s

Question 2: If a person’s reflex response time increases to 0.35 seconds during fatigue, what is the percentage increase compared to the normal response time of 0.25 seconds?

Answer: Percentage increase = [(0.35 - 0.25) / 0.25] x 100 = (0.10 / 0.25) x 100 = 40%

Question 1: Describe a simple experiment to test the reflex response of the knee-jerk reflex.

Answer: The experiment involves tapping the patellar tendon with a reflex hammer while the person is seated with legs dangling. The response is the extension of the lower leg. Variables include the force of the tap (independent), leg response (dependent), and patient positioning (controlled). Safety precautions include ensuring the person is seated securely and avoiding excessive force to prevent injury.

Question 2: Identify two variables that should be controlled in an experiment testing reflex responses.

Answer: Variables to control include the force of the stimulus and the position of the limb.

Question 1: A group of students measured their reflex response times before and after consuming caffeine. The average response time before was 0.30 seconds, and after was 0.25 seconds. What does this data suggest about caffeine’s effect on reflex response?

Answer: The data suggests that caffeine may enhance nerve impulse transmission or alertness, resulting in faster reflex responses.

Question 2: In a scenario where a reflex response is delayed, list three possible factors that could contribute to this delay.

Answer: Possible factors include nerve damage, fatigue, or the presence of nerve-inhibiting substances in the body.

Question 1: Explain why the reflex arc is considered an important protective mechanism for the body.

Answer: The reflex arc allows for rapid responses to potentially harmful stimuli, such as touching something hot or sharp, without the delay of routing signals through the brain. This quick response minimizes injury and helps maintain homeostasis.

Question 2: Describe a real-world example where understanding the reflex arc could help in medical or technological applications.

Answer: Understanding the reflex arc can aid in designing prosthetics that mimic natural reflexes or developing treatments for nerve damage to restore rapid response functions.

Question 3: Which component of the reflex arc acts as the relay between sensory and motor neurons?

Answer: Relay neuron