29 सितंबर, 2011
electric current is produced in the human body too
Extremely weak electric current is produced in the human body by the movement of charged particles (ions), called ionic currents. When weak ionic currents flow along the nerve cells, they produce a magnetic field in our body. For example, when we touch something with our hand, our nerves carry electric impulse to the appropriate muscles. And this electric impulse creates a temporary magnetism in the body. The magnetism produced in the human body is very, very weak as compared to the Earth’s magnetism. The two main organs of the human body where the magnetic field produced is quite significant are the Heart and the Brain. In the human eye, an image is formed by the lens on the retina (which is made up of light sensitive cells rods and cones). Optical signals are converted into electrical signals by these optical cells. The Outer ear collects sound which vibrate the ear drum and cochlea converts it into electrical signals. When we taste, taste buds presents on the tongue converts it into electrical signals. For example when we touch lemon juice we feel a strong sensation. In our body electro-chemical reaction is going on due to which we think, feel, see etc. Our brain perceives everything in terms of electrical signals. Our feeling anger, happiness, and sadness are because of electro-chemical reaction which produces electrical signals. The magnetism produced inside the human body forms the basis of a technique called Magnetic Resonance Imaging (MRI) which is used to obtain images of the internal parts of our body. MRI is an important tool in medical diagnosis because through MRI scans doctors see the internal parts of the body. Magnetism in animals like the aquatic bacteria, shrimps, dolphins and whales etc, is due to the presence of little crystal of magnetite (lodestone) in their bodies. These magnetic crystals are formed from iron (which is taken in by the animals from water) and oxygen which they breathe in. The magnetic crystals present in the animals act as internal magnetic compasses and help the animal to respond to the Earth’s magnetic field. For example, several species of aquatic bacteria use their in-built magnets to swim along the Earth’s magnetic field. Interesting and true!