Question 1: The reflex arc is a rapid, involuntary response mechanism that enables the body to react quickly to stimuli, protecting tissues from damage. It involves sensory receptors, sensory neurons, a relay neuron in the spinal cord, motor neurons, and effectors such as muscles.

Answer: The reflex arc is a fast, involuntary response pathway involving sensory receptors, sensory neurons, relay neurons, motor neurons, and effectors to protect tissues from harm.

Question 1: Define the term 'reflex arc'.

Answer: A neural pathway that mediates a reflex action, involving sensory input and motor output without conscious brain involvement.

Question 2: List the main components involved in a typical reflex arc.

Answer: Sensory receptor, sensory neuron, relay neuron, motor neuron, effector.

Question 3: Explain why reflex actions are faster than voluntary responses.

Answer: Reflex actions are faster because they bypass the brain and involve fewer synapses, allowing quicker responses.

Question 1: The length of a nerve pathway involved in a reflex is 1.2 meters. If the nerve impulse travels at a speed of 60 meters per second, calculate the time taken for the impulse to travel this distance. Use the formula: Time = Distance / Speed. Give your answer in milliseconds.

Answer: 20 milliseconds

Question 2: A stimulus triggers a reflex response with a latency of 25 milliseconds. If the nerve impulse speed increases to 75 meters per second and the nerve pathway length remains unchanged at 1.8 meters, what is the new latency? Show your calculation.

Answer: Latency = Distance / Speed = 1.8 / 75 = 0.024 seconds = 24 milliseconds.

Question 1: Describe a safe and ethical method to investigate the reflex response time in humans.

Answer: Use a simple reflex test such as the finger snap test, ensuring participants are informed, consent is obtained, and safety precautions are followed to avoid injury.

Question 2: Identify three variables that should be controlled during a reflex response time experiment.

Answer: Age of participants, time of day, environmental conditions (e.g., temperature, lighting).

Question 1: In a study, the average reflex response time of a group of students was recorded as 25 milliseconds with a standard deviation of 3 milliseconds. A new drug is suspected to improve nerve conduction. After administration, the average response time drops to 20 milliseconds with a standard deviation of 2 milliseconds. How would you interpret this data?

Answer: The data suggests that the drug may improve nerve conduction speed, as the average response time has decreased. Statistical analysis would be needed to determine significance.

Question 1: Describe how the reflex arc is involved in the withdrawal reflex when touching a hot object.

Answer: When skin receptors detect heat, sensory neurons transmit impulses to the spinal cord, where relay neurons process the information. Motor neurons then send impulses to muscles, causing rapid withdrawal of the hand to prevent burns.

Question 2: Explain how understanding reflex arcs can be applied in designing prosthetic limbs or neural interfaces.

Answer: Knowledge of reflex arcs helps in creating prosthetics and neural interfaces that can mimic rapid, involuntary responses, improving functionality and safety by integrating sensory feedback and automatic motor responses.

Question 3: A person’s reflex response time is significantly delayed. What could be some possible reasons for this delay?

Answer: Possible reasons include nerve damage, neurological disorders, fatigue, or interference from substances such as alcohol or drugs.