The document discusses the use of microcontrollers in biomedical applications. It begins by explaining that microcontrollers are preferable to microprocessors for implants because they are smaller, use less power, and have onboard memory and I/O functions. Examples of biomedical devices that use microcontrollers include sensors that monitor temperature, blood pressure and blood sugar levels, implants like pacemakers, and functional electrical stimulation devices. Microcontrollers are well-suited for these applications because they are small, flexible, low power, and can interface with sensors and actuators. The document concludes by specifically examining how microcontrollers are used in pacemakers and deep brain stimulation devices to treat conditions like Parkinson's disease.