Which one of the following pairs of structures distinguishes a nerve cell from other types of cells?
(a) Why are nerve cells long and have branches ? (b) What is the other name of a nerve cell ?
P is a cell (or group of cells) in the human body which is sensitive to a particular type of stimulus and conveys the message to CNS through nerves Q. On the other hand, R is part of the human body which can respond to a stimulus according to the instructions sent from the CNS through nerves S.
(a) What is P ? Name give organs which contain cells (or group of cells ) like P.
(b) Name the nerves Q.
(c) What is R ? Give two examples of R.
(d) Name nerves S.
(e) How do messages travel through the nerves Q and S ?