Get to know the functions of your heart, blood vessels, and blood itself and how they work together to maintain your health.

The endocrine system is the name for the glands that produce hormones in a person’s body. These glands include the thyroid gland, pituitary gland, and adrenal gland. The endocrine system produces hormones such as insulin, estrogen, testosterone, and ...

Your nervous system is a network that sends signals between your brain and other parts of your body to control your body's movements and processes. This system includes your brain, spinal cord, and nerves. Your parasympathetic nervous system (PSNS) is ...

Your sympathetic nervous system is one of the branches of your autonomic nervous system. It controls functions under unconscious control related to “fight or flight.” Your nervous system plays a critical role in almost all bodily functions. Without it ...