The nervous system and homeostasis are fundamental topics in GCSE Biology that help students understand how the body maintains internal balance and responds to changes.
The nervous system consists of the central nervous system (brain and spinal cord) and peripheral nervous system (network of nerves). Neurons are specialized cells that carry electrical impulses through the body, allowing for rapid responses to stimuli. These responses involve receptors detecting changes, sensory neurons carrying signals to the CNS, processing in the brain or spinal cord, and motor neurons triggering effectors like muscles or glands. Understanding this pathway is crucial for GCSE Biology exam questions that often test students' knowledge of reflex arcs and response times.
Homeostasis maintains optimal internal conditions through negative feedback loops. A key example is blood glucose regulation, where the pancreas produces insulin when levels are too high and glucagon when levels are too low. When blood glucose rises after eating, insulin triggers cells to take up glucose and convert excess into glycogen for storage in the liver and muscles. Conversely, when blood glucose falls, glucagon causes the breakdown of glycogen back into glucose. This process demonstrates how hormones from the endocrine system work together to maintain balance. The specification also covers other homeostatic processes like temperature regulation and water balance, which frequently appear in exam questions. Students should be able to interpret graphs showing blood glucose fluctuations and explain the roles of different hormones in maintaining homeostasis. These topics are particularly important for understanding diseases like diabetes and their treatments, making them relevant to both exam success and real-world applications in medicine and healthcare.
