Ultrasound

Ultrasound

To understand what ultrasound is and what it’s used for, we must first understand what sound is.

Sound occurs when things vibrate. These vibrations are transferred to the air particles of its surrounding. This causes a chain reaction in the air particle vibrations, causing them to move like waves. These waves are called sound waves and are longitudinal, meaning they travel horizontally. When the sound waves reaches our ears, it vibrates the ear drum. The ear drum sends the vibrations to three small bones that are put together. In this order, they are called the hammer, the     

anvil and the stirrup. This series of bones

amplifies and transports the vibrations

further into the ear, reaching the cochlea. The cochlea transforms the vibrations into electrical impulses which can be understood by the brain. The auditory nerve sends the electrical impulses to the brain.

Sound waves can have different frequencies. A low note has a low frequency and a high note has a high frequency. Frequency means how many waves there are in one second, which we measure in Hz (Hertz). If there is a note with a frequency of 500, there are 500 waves reaching the ear or an oscilloscope in one second. We measure frequency in Hz. Humans can only hear sound between the frequencies of about 27 and 20 000 Hz. A frequency below 27 Hz is called infrasound and a frequency above 20 000 is called ultrasound.

We can’t hear ultrasound or infrasound because our ear isn’t sensitive enough.

Even though we can’t hear ultrasound, it is used to treat many medical issues like looking inside the body(at unborn babies) and breaking down kidney stones. When looking at a fetus you are essentially sending ultrasonic waves towards it using a doppler scanner. The scanner sends out the waves as well as recognizes the changes in the reflected waves as they pass through different tissue. We call the reflected waves echoes. The scanner sends its data to a computer that processes it. The finished image is then shown on a TV screen (images changes as you move the scanner).

Ultrasound scans are much safer and better in some cases than x-rays. Ultrasound scans does not hurt living cells as it's just sound passing through the body. It also gives a better image of soft tissue compared to x-rays which only shows hard organs like bones and tumors. X-rays hurt living cells a lot as it is radioactive rays passing through the body.

- Erik & Leo