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How do nervous tissue cause action? |
| Answer» \tNervous tissue is the main component of the nervous system,\xa0which regulates and controls body functions.\xa0It is specialised to react to stimuli and to conduct impulses to various organs in the body which bring about a response to the stimulus.\tNervous tissue\xa0is composed of neurons, which transmit impulses, and the neuroglia, which assist propagation of the nerve impulse as well as provide nutrients to the neuron. Neurons are easily stimulated and transmit impulses very rapidly.\tNerve cells communicate with each other at a junction known as a synapse, where the terminal branches of an axon and the dendrites of another neuron lie in close proximity to each other but normally without direct contact. Information is transmitted across the gap by chemical secretions called neurotransmitters. It causes activation in the post-synaptic cell. Thus impulses pass from one neuron to the next.\tNervous tissue allows an organism to sense stimuli in both the internal and external environment.\tThe stimuli are analysed and integrated to provide appropriate, co-ordinated responses in various organs.\tThe afferent or sensory neurons conduct nerve impulses from the sense organs and receptors to the central nervous system.\tConnector neurons supply the connection between the afferent and efferent neurons as well as different parts of the central nervous system.\tEfferent or somatic motor neurons transmit the impulse from the central nervous system to a muscle (the effector organ) which then react to the initial stimulus.\tAutonomic motor or efferent neurons transmit impulses to the involuntary muscles and glands. | |