HOW ULTRASOUND WORKS: Ultrasound is a medical imaging technique that uses high-frequency sound waves and their echoes. It is similar to the echolocation that bats use to navigate in the dark and the SONAR that submarines use to navigate underwater.. An ultrasound machine transmits high-frequency sound pulses into the body through a probe. The sound waves travel until they hit a boundary between two kinds of tissue-for example, the boundary between soft tissue and bone. When this happens, some of the sound waves are reflected back to the probe, while others travel further through the body until they hit another boundary. All the reflected waves or "echoes" are recorded by the machine, which then calculates the distance each sound wave traveled based on how long it took the sound wave's echo to return. This data is used to form a two-dimensional image based on the distances and intensities of the echoes.
ABOUT THE NERVOUS SYSTEM: The brain is "hardwired" with connections, which are made by billions of neurons that make electricity whenever they are stimulated. The electrical patterns are called brain waves. Neurons act like the wires and gates in a computer, gathering and transmitting electrochemical signals over distances as far as several feet. The brain encodes information not by relying on single neurons, but by spreading the information across large populations of neurons, and by rapidly adapting to new circumstances. Motor neurons carry signals from the central nervous system to the muscles, skin, and glands of the body, while sensory neurons carry signals from those outer parts of the body to the central nervous system. Receptors sense things like chemicals, light, and sound and encode this information into electrochemical signals transmitted by the sensory neurons. And interneurons tie everything together by connecting the various neurons within the brain and spinal cord. The part of the brain that controls motor skills is located at the rear of the frontal lobe.
The Acoustical Society of America contributed to the information contained in the TV portion of this report.