The Structure and Function of the Cell

A stack of red blood cells are shown to illustrate that cells are the smallest units of life.

How many cells does the human body consist of? The answer to this question is not as simple as the question. The reason being, all cells are not the same. Cells are differentiated in the manner required for function in the body system it is associated with. With that said, we will explore the general structure and function of eukaryotic cells.

To answer the question, only an estimation of the number of cells in the human body can be provided. Research published in The Annals of Human Biology (2013) estimates that the human specimen consists of 37.2 trillion cells. Unlike previous estimates, this study provides an analysis of each organ in the human body.

Take this opportunity to explore the Cell Theory video below for more historical information on the cell.

Cell Theory Video

Before we begin to explore the parts and functions of a single cell, consider the size of the subject matter. A favorite childhood story introduces the size and function of a city on something as small as a speck of dust. As we explore the structure and function of the human cell, the functions will align with that of a city.

The major structural parts of all cells in the human body are the nucleus, cytoplasm, and cell membrane. Cells in the human body are described as eukaryotic cells, indicating that the nucleus is separated from the cytoplasm by a membrane. The cell membrane functions as a selective filter allowing certain materials to either enter the cell or exit the cell.

Now, let's take a closer look at the parts and functions of a cell.

Cells are constantly functioning and maturing. Therefore, a constant demand exists for cellular reproduction. Cellular reproduction occurs through a process called mitosis in all cells (with the exception of sex cells).

Let's take a look at the process of Mitosis.

Mitosis Video

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