A system (including the thymus and bone marrow and lymphoid tissues) that protects the body from foreign substances and pathogenic organisms by producing the immune response.A system that provides a defense mechanism to organism, providing defensive measures against antigens which would prove harmful to the organism.
Ultrasound is a type of imaging. It uses high-frequency sound waves to look at organs and structures inside the body. Health care professionals use it to view the heart, blood vessels, kidneys, liver, and other organs. During pregnancy, doctors use ultrasound to view the fetus. Unlike x-rays, ultrasound does not expose you to radiation. During an ultrasound test, you lie on a table. A special technician or doctor moves a device called a transducer over part of your body. The transducer sends out sound waves, which bounce off the tissues inside your body.
Ultrasound is an imaging modality that utilizes high-frequency sound waves to provide cross-sectional images of the body. The ultrasound machine has the following components: monitor, keyboard, processor, data storage and probe or transducer. A transducer performs two functions: it emits sound waves (echoes) at a certain frequency and captures the returning echoes at frequencies dependent on the tissues through which the waves traverse. The sound wave that is returned to the transducer is digitized to appear as echoes or dots on the screen.