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Question
The human body contains a large number of cells A which are very long and branched, and look like electric wires. The longest branch of this cell is B whereas there are many small branches C. Any two A cells do not join to one another completely in the human body. There is a microscopic gap D between every pair of adjacent A cells through which electric impulses can pass by the release of a chemical substance.
(a) What are cells A?
(b) What is the name of (i) branch B, and (ii) branches C?
(c) What is the microscopic gap D known as?
(d) What is the function of cells like A in the human body?
(e) The cells A are of three types. name the three types.
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Solution
- A represents neurons. Neurons are the largest cells in the human body, which look like electric wires.
- (i) B represents the axon.
(ii) C represents the dendrites.
- The microscopic gap D is known as a synapse. A synapse is a functional junction between a pair of adjacent neurons over which nerve impulses can pass.
- A neuron transmits messages to and from the central nervous system. It is the structural and functional unit of the nervous system.
- The three types of neurons are sensory neurons, motor neurons and relay neurons.
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