INTRODUCTION The cell is the basic structural and functional unit of all living organism. It is the smallest unit of life, and is often called the building block of life. A group of cells together form tissues. Group of tissues together form an organ. Many organs together form a system.

MUSCLES Muscles is a contractile tissue derived from mesodermal layer.Their function is to produce force and motion. Cardiac muscles: They are involuntary striated muscles found in heart. Smooth musles: It is involuntary non striated muscles. Skeletal muscles:They are voluntary striated muscles.Contraction and relaxation of these muscles causes locomotion.

ELECTROENCEPHALOGRAM (EEG) The brain generates rhytmic potentials which originate in individual neuron of the brain. These potentials get summated as millions of cell discharge,the recording of which is known as EEG. The neurons are electrically polarized at rest. The interior of neuron is at potential -70mv.when a neuron is exposed to a stimulus above a threshold a nerve impulse seen as a change in membrane potential is generated resulting in depolarization of the cell. Shortly afterwards repolarization occurs.

The EEG can be picked up with electrodes either from scalp or from cerebral cortex. The EEG signal has no standard waveform. Is is classified into 5 frequency bands: 1.DELTA:0.5-4 hz 2.THETA:4-8hz 3.ALPHA:8-13hz 4.BETA:13-22hz 5.GAMMA:22-30hz The frequency of EEG is affected by mental activity of person.

ELECTROMYOGRAM (EMG) The contraction of skeletal muscles results in action potential in individual muscle fibers, the recording is known as EMG. The activity is similar to cardiac muscle but in skeletal muscle repolarization takes place more rapidly. The EMG pattern is usually a summation of individual action potentials from the muscles being studied. Surface electrodes are used to measure the electrical activity of underlying muscle mass.

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