OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

How does shivering help maintain body temperature?

1. It decreases blood flow to the extremities

2. Muscle contractions increase respiration and heat production

3. It triggers sweat production

4. It increases the amount of glycogen in muscles

The correct answer is: Muscle contractions increase respiration and heat production

Shivering plays a crucial role in thermoregulation by generating heat through rapid muscle contractions. When the body temperature drops, the hypothalamus in the brain detects this change and initiates shivering as a response. The muscles contract and relax involuntarily, which requires energy. This energy is obtained through cellular respiration, a process that metabolizes glucose and produces heat as a byproduct. As a result, the increased muscle activity from shivering significantly enhances heat production, helping to raise the body's core temperature back to a normal level. The other options do not accurately describe the role of shivering in temperature regulation. Shivering does not involve reducing blood flow to extremities or triggering sweat production, as those processes would act to cool the body rather than warm it. Additionally, shivering does not directly increase glycogen levels in muscles; rather, it utilizes stored glycogen to fuel the increased metabolic activity needed for heat production.