Preksha Dhyana Human Body

SR No.: 006549
Original Sutra Author: N/A
Author: Jethalal S Zaveri
Publisher: Jain Vishva Bharati
Publication Year: 1982
Total Pages: 140
Language: English
Classification: Book_English & Yoga
File Size: 6 MB

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Preksha Dhyana :
the periphery to the C.N.S. and (ii) motor or efferent neurons transmit messages from the C.N.S. to a muscle, a gland or some other tissue and produce an action. In some cases the impulse is transmitted along a chain of motor neurons, each relaying the message from its axon to the dendrites of the next neuron in line. Dendrites are extensions of the cell body. They look rather like tree-branches. Branching greatly increases the receptive surface of the neuron. The terminal branches of an axon of a particular neuron are often associated with dendrites of a number of other neurons, and the dendrites of each particular neuron in turn, may be linked with tha axons of a number of other neurons. A nerve impulse thus may be transmitted over an intricate net-work of converging and diverging pathways. Although each neuron functions essentially independently of those around it, it is the collective action that results in our sensations, movements, thoughts and speech, affecting virtually everything that goes on in our body. Physiology of the Neuron
A neuron 'fires' or transmits an impulse along its entire - length when it receives a suitable stimulus. If the stimulus is below a certain level (threshold), the impulse will not be transmitted. After a neuron has fired, it requires a certain time to recover; until it has recovered, it cannot fire again, even if a new stimulus is applied. This refractory period is from 0.0005 to 0.002 second.
Analogy of conduction of electricity along a wire does not hold good in several important respects. A nerve impulse is not a simple electric current. Firstly, it retains its strength, no matter how far it must travel, for it is continually being renewed as it passes along. Secondly, the speed of nerve transmission is much slower, only about 20 metres per second as against the speed of electric current transmission which is 3,00,000 k.m.sec. (=velocity of light).
The Synapse : The successive neurons in a nerve tract 1. All these aspects of neuronal functioning have been mimicked with
suitable arrangement of electronic components-condensers, resistors, transistors - and neatly soldered inter-connecting wires on a small plate called chip or integrated circuits.