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

Which part of the nervous system detects changes in temperature?

1. Receptors in the ears

2. Receptors in the eyes

3. Receptors in the skin

4. Receptors in the mouth

The correct answer is: Receptors in the skin

The correct answer highlights the role of skin receptors, specifically thermoreceptors, which are specialized nerve endings located in the skin that detect changes in temperature. These receptors are crucial for assessing the external environment's thermal conditions, allowing the body to respond appropriately to prevent overheating or excessive cooling. Thermoreceptors play an essential role in homeostasis by sending signals to the brain, which then initiates necessary physiological responses such as sweating to cool down or shivering to increase body temperature. The skin is the primary interface with the environment, making its receptors vital for this sensing function. In contrast, receptors located in the ears, eyes, and mouth serve different sensory functions. Ear receptors are mainly involved in hearing and balance, while eye receptors are responsible for vision. Mouth receptors primarily detect taste and are not specialized for temperature changes.