Relationship between cells, organs, and the whole body

[Bernard NebelKeymaster]

The objective of this lesson to have kids under stand the relationship between cells, organs, whole body. While it is natural to focus in the human, the same relationships and concepts hold for the entirety of the animal kingdom.

Review/emphasize:

All parts, tissues, and organs of the body are comprised of cells: Recall! The entirety of the body is derived from a single cell, the fertilized egg. Recall: cell devision, cell growth, and cell differentiation. In total, the human body is made from some 30 to 40 trillion cells, that’s 30 – 40,000,000,000,000 cells.

Each cell is a basic unit of life.

To function in the body, each cell must maintain it own life alongside the special function(s) it performs in the body. Maintaining its own life, plus whatever function it performs in the body, e.g. contraction of muscle fibers if it is a muscle cell, conducting nerve impulses if it is a cell of the nervous system, means that each cell have:

1. Energy — each cell derives its own energy via cellular respiration, i.e. glucose + oxygen —-> carbon dioxide  + water + energy. .
2. Glucose and oxygen — The cell’s requirement for energy translates to a constant demand for glucose and oxygen and the means to dispose of carbon dioxide.
3. Additional nutrients, (e.g. nitrogen, potassium, calcium, iron, et al.) to maintain itself and produce whatever special product(s) its function demands. For example, cells of the salivary glands need, nitrogen (contained in amino acids) to produce the protein enzyme in saliva needed to begin digestion. Red blood cell require amino acids to and iron to produce hemoglobin, the protein “enzyme” that carries oxygen.  

Summarizing: every living cell requires a constant supply of 

1. Nutrients (glucose, amino acids, and others) for energy, self maintenance, and production of special products
2. Oxygen, for cell respiration
3. Ability to dispose of CO2 and other wastes.

To perform all things a cell dose, a cell is no simple thing. Research over they years has revealed the cell to be an infanitely complex structure as seen via the following link. Scroll down for addition images) (Don’t have kids get bogged down in memorizing the various parts and structures within cells. This should be shown only to emphasize with the fantastic job a cell must be doing in just maintaining itself. Add to this is any special function the cell is performing. Keep reminding kids that each individual cell is microscopic. Therefore structures within cells are submicroscopic (not visible with a light microscope)—reveled only by using the electron microscope.

https://sites.google.com/a/coe.edu/kim-schorn-practicum/home/lesson-3

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