Tiny fields inside the body
Nerve currents make magnetic fields too.
Currents in the body
When you touch something, your nerves carry a tiny electric impulse to your muscles. This is a very weak current of charged particles called ions.
Does such a weak current produce a magnetic field?
What this lesson covers
The idea
An electric current always produces a magnetic field: even the weak ion currents along nerve cells produce very weak magnetic fields, which are significant in the heart and the brain.
Currents in the body
When you touch something, your nerves carry a tiny electric impulse to your muscles. This is a very weak current of charged particles called ions.
Does such a weak current produce a magnetic field?
- Yes, a very weak one
- No, only large currents produce magnetic fields
- Yes, as strong as the earth's field
Magnetism in medicine
Open each tab to see how currents in the body produce magnetic fields.
Always a field
An electric current always produces a magnetic field. This is true even for the weak ion currents that travel along nerve cells. Their fields are very weak, about one-billionth of the earth's magnetic field. The fields are significant in the heart and the brain. Pictures made with the magnetic field inside the body are used in medicine.
An electric current always produces a magnetic field: even the weak ion currents along nerve cells produce very weak magnetic fields, which are significant in the heart and the brain.
Notes
An electric current always produces a magnetic field, even the weak ion currents in nerve cells; these fields matter in the heart and brain.
Check yourself
An electric current always produces…
How strong are the magnetic fields produced by the ion currents along nerve cells?
In which two organs is the magnetic field produced in the human body significant?
The magnetic field inside the body is the basis of a technique that gives images of body parts. It is called…
- a magnetic field — correct. Yes!
- heat but no magnetic field. An electric current always produces a magnetic field. Heating is a separate effect.
- a magnetic field only in a metal wire. Even the weak ion currents that travel along nerve cells in the body produce magnetic fields.
- As strong as the earth's magnetic field. These fields are very weak, about one-billionth of the earth's magnetic field.
- Very weak, about one-billionth of the earth's magnetic field — correct. Yes!
- A thousand times stronger than the earth's magnetic field. These fields are about one-billionth of the earth's magnetic field, so they are far weaker.
- The lungs and the stomach. The book names the heart and the brain as the two organs where the magnetic field is significant.
- The eyes and the ears. The heart and the brain are the two organs where the magnetic field is significant.
- The heart and the brain — correct. Yes!
- Magnetic Resonance Imaging (MRI) — correct. Yes!
- Electric Current Mapping. The technique is called Magnetic Resonance Imaging, MRI.
- Earth Wire Imaging. The technique is called Magnetic Resonance Imaging, MRI. The earth wire is a safety wire in house circuits.