We start with the cell, because so much of what happens to us when we get sick, and how we get healthy again, can be explained by what happens on a cellular level. The cell is extremely complex and I will only touch on the basics in these posts, but at least we can have a rudimentary understanding.
Structure of cells
A cell has three basic parts:
1) Plasma membrane: A membrane lies at the border of cells and consists of lipids and proteins. See my post of 23 May on the cell membrane
2) Cytoplasm: All the cellular contents between the plasma membrane and the nucleus and can be further divided into the Cytosol and Organelles. We will discuss the organelles in today's post.
3) Nucleus: Technically an organelle, but usually considered separately because of its numerous and diverse functions.
Organelles
Organelles are specialized structures that evolved to perform specific functions. We could probably discuss each organelle in a separate post, because each one has it's own characteristic shape and function. i decided to keep this very basic and just list the different organelles, what they look like and what their basic function is. We will also just look at the "famous" organelles. There are other organelles, but the ones we discuss will give us a good understanding of what goes on inside the cell.
Endoplasmic reticulim (ER): A network of membranous tubules that extend from the nuclear membrane to the cell membrane. The ER can further be subdivided into a rough and smooth. The rough ER is continuous with the nuclear membrane and has an outer surface studded with ribosomes. The ER function is to be a passageway for the transport of materials within the cell. It also synthesizes lipids and proteins.Ribosomes: These are either floating bodies for the internal needs of the cell or attached to the ER for transport out of the cell. Ribosomes are the sites for protein synthesis.
Golgi apparatus: Besides having a cool name (named after the scientist that discovered it), it refines and moderates proteins produced in the ER prior to transport and packages materials for secretion from the cell. It is a series of membranous sacs, described as looking like a stack of pita bread.
Mitochondria: These organelles are roughly bean-shaped with inner membranes. They are (literally) the powerhouses of the cell. They break down sugar molecules into energy. Tissues that need a lot of energy, like muscles, have more of these organelles in their cells .
Lysosomes: They are single membrane structures and have a membrane. The lysosome breaks down larger molecules into smaller molecules and it also digests old cell parts. It is the waste manager of the cell. It has powerful digestive enzymes to break down the waste.
Chromatin: Fibers composed of protein and DNA molecules. It contains the genetic information for protein synthesis. It is the heredity material in cells
Sentriole: A pair of rod shaped structures perpendicular to each other. It plays an important part in cell division. It organizes the spindle fibers during cell division.
These are some of the most common organelles. It is easy to understand that what goes on in the cell can have a huge impact on tissues and systems and therefore on the disease process.
How does it affect you?
In cancer, it has been known since the 1930's that mitochondria, the powerhouse of the cell, dysfunctions when cancer is present. Until recently, researchers believed that the damage to mitochondria is the result, not the cause of cancer, but recent research has brought this into question. I'll have more details about this research in a future post.
1. Riana,
As a survivor I have gradually learned more about cell basics, but I had no idea how complex cells were until the last few years. While I knew better, my image of cells was like the cartoon in your blog. What most impressed me was that some types of cells have more than a million receptors on the surface of each cell. It's as if each cell inside us is a galaxy with an awesomely huge number of parts. I'm beginning to appreciate that they are indeed "extremely complex" as you described them in your blog.
Jim Waldenfels http://www.mycancerplace.com/profile.php?id=147
Posted at 12:31PM on Jun 3rd 2007 by Jim Waldenfels