Page 24 - SCERT Kerala State Syllabus 8th Standard Basic Science Textbooks English Medium Part 1_Neat

Diversity among cells

Each part of the human body is made up of millions of
different kinds of cells. There are about 200 different kinds
of cells like nerve cells, muscle cells, blood cells, bone cells
etc., in the human body.

What a wonder our body is!
How do millions of such cells
function effectively without
getting messed up?

Yes, the human body is indeed a wonder. The well-being of the
human body depends on the systematic and regulated action of
the cells. Similar cells function together in groups, not separately.
Such clusters of cells are called tissues.

Tissues

Tissues are groups of similar cells that have a common origin
and perform specific functions. There are different kinds of tissues
in multicellular organisms like plants and animals. The co-
ordinated action of these tissues helps in performing different
physiological functions effectively.
Have you observed the muscle cell and nerve cell in Illustration
2.1? Though both are cells, they differ so much in appearance.
What may be the reason for the differences?

How do these differences influence the physiological functions?
Conduct a discussion on the description given below on the basis
of the indicators.

Basic Science VIII 23