OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

Disable ads (and more) with a membership for a one time $2.99 payment

Study for the OCR GCSE Biology Exam. Use multiple choice questions and quiz flashcards with explanations and hints. Excel in your exams!

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

Practice this question and more.

How does magnetic resonance imaging (MRI) work?

It uses sound waves to create images
It uses magnetic fields to produce images of the brain
It relys on injecting dyes for visibility
It measures electrical conductivity in neurons

The correct answer is: It uses magnetic fields to produce images of the brain

Magnetic resonance imaging (MRI) operates by exploiting the principles of strong magnetic fields and radio waves to generate detailed images of internal structures, particularly soft tissues such as the brain. When a patient is placed in the MRI machine, the magnetic field aligns the hydrogen atoms in the body, which are abundant due to the high water content of tissues. Following this, radiofrequency pulses are applied, causing these atoms to emit signals as they return to their original alignment. These signals are then captured and processed to create comprehensive cross-sectional images of the organs and structures within the body. The other options reflect different imaging techniques or principles. For instance, sound waves are utilized in ultrasound imaging, while X-rays or CT scans may require the injection of dyes for improved contrast. The measurement of electrical conductivity in neurons pertains to other methods such as electroencephalography (EEG) rather than MRI. This differentiation is crucial in understanding the specific applications and technologies associated with each medical imaging technique.