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.

(a) In above question, cells A are neurons or nerve cells.

(b) (i) Branch B is axon and (ii) C branches are dendrites.


(c) The microscopic gap D is known as synapse.


(d) Cell A or Neurons transmit electrical signals or impulses to and from the central nervous system.


(e) Cell A or Neurons are of three types: Sensory neurons, motor neurons and relay neurons.


101