| Cells Into Tissues |
Uni-cellular vs. Multi-cellular Organisms
Some single-cell organisms are
capable of surviving independently.
They can obtain and digest their food,
eject their wastes, and carry out all the
other activities necessary to keep
themselves alive. But in multicellular
organisms, like the human body, cells
do not operate independently. Instead
they form tight cell communities that
live and work together.
Some single-cell organisms are
capable of surviving independently.
They can obtain and digest their food,
eject their wastes, and carry out all the
other activities necessary to keep
themselves alive. But in multicellular
organisms, like the human body, cells
do not operate independently. Instead
they form tight cell communities that
live and work together.
| An amoeba, a uni-cellular creature. |
| A cat is an example of a multi-cellular organism. photo: Greg Tompos |
Cell Specialisation
Individual body cells are specialised, with
each type performing specific functions that
help maintain homeostasis (or a stable
internal environment) and benefit the body
as a whole. The specialisation of our cells
is obvious. Muscle cells look and act quite
differently to skin cells, which in turn are
easy to distinguish from brain cells. Cell
specialisation allows the body to function in
very sophisticated ways.
Individual body cells are specialised, with
each type performing specific functions that
help maintain homeostasis (or a stable
internal environment) and benefit the body
as a whole. The specialisation of our cells
is obvious. Muscle cells look and act quite
differently to skin cells, which in turn are
easy to distinguish from brain cells. Cell
specialisation allows the body to function in
very sophisticated ways.
| One nerve cell (centre) with several others visible in the background. |
| from: tonydude.net/NaturalScience100/Topics/3Mind/timages_mind/nerve_cell.jpg |
| At left you can see how a large number of muscle cells are combined to make a tissue. |
| from: www.bioanim.com/CellTissueHumanBody6/O3muscle/misicFun1lgws.html |
Tissues
Groups of cells that are similar in structure and perform a common or related function are
called tissues. Four primary tissue types interweave to form the ‘fabric’ of the body. These
basic tissues are epithelial, connective, muscle, and nervous tissue, and each has
numerous sub-varieties. Briefly, epithelial tissues cover the body surface and line its
cavities; muscle tissue causes movement; connective tissue supports the body and protects
its organs; and nervous tissue provides a means of rapid internal communication by
transmitting electrical impulses.
Groups of cells that are similar in structure and perform a common or related function are
called tissues. Four primary tissue types interweave to form the ‘fabric’ of the body. These
basic tissues are epithelial, connective, muscle, and nervous tissue, and each has
numerous sub-varieties. Briefly, epithelial tissues cover the body surface and line its
cavities; muscle tissue causes movement; connective tissue supports the body and protects
its organs; and nervous tissue provides a means of rapid internal communication by
transmitting electrical impulses.
| Factual information contained on this page: Marieb, E. N. (1998). Human Anatomy & Physiology. Benjamin/Cummings Publishing. |
| For revision, please follow the links to the Check Your Knowledge site to complete the revision for this section. Using information found on this site as well as on the Body Tissues Website, define each of the four types of tissues and give examples of each before turning in your answer sheet to your teacher. |
| University of Canberra IT and Education Nick Moss & Greg Tompos October 2005 |
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| from: www.somewhere.on/the/internet/ |