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

The pituitary gland is often referred to as the "master gland" of the endocrine system because it produces and secretes a variety of hormones that play significant roles in regulating important bodily functions. One of its primary functions is to produce hormones that are crucial in the regulation of several physiological processes, including growth, metabolism, and reproduction. In particular, the pituitary gland releases hormones that are directly involved in the menstrual cycle, such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These hormones help regulate the growth and release of eggs from the ovaries and affect menstrual cycles, making it a key player in female reproductive health. The other options refer to functions that are regulated by other glands or organ systems. For example, digestion is primarily facilitated by hormones produced in the pancreas and gastrointestinal tract, whereas blood sugar levels are notably regulated by insulin from the pancreas. The immune response is largely coordinated by various components of the immune system, including cells and tissues, rather than directly by the pituitary gland.