I am a Licensed Practical Nurse with five years' experience in this profession. I believe it is essential to go back to the basics in all things in order to really understand them. I am fascinated by how our bodies work and I hope I can get my readers to share my fascination. I hope we all learn new things and marvel again at the things we already know. This feature -- which includes a closing section on how disease affects the topic in question -- will run on The Cancer Blog on Wednesdays, and The Cardio Blog and The Diabetes Blog on Thursdays. [The contents in this post are for informational purposes only and should not be construed as medical advice or substitute for professional medical care.]

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: This post will discuss the membrane in more detail.

2) Cytoplasm: All the cellular contents between the plasma membrane and the nucleus and can be further divided into the Cytosol and Organelles.

3) Nucleus: Technically an organelle, but usually considered separately because of its numerous and diverse functions.

Membrane

A membrane lies at the border of the cells. It consists of lipids and proteins.

Phospholipids (one of the three classes of membrane lipids) are formed into what is called a lipid bilayer. This occurs because it is amphiphilic (containing both hydrophobic and hydrophilic properties).The hydrocarbon tails of the molecule are hydrophobic (water repelling) and its polar head is hydrophilic (water loving). As the plasma membrane faces watery solutions on both sides, its phospholipids accommodate this by forming a phospholipid bilayer with the hydrophobic tails facing each other. Picture a row of heads facing the outside of the cell -- which contains water -- with the tails facing in and another layer of the heads facing the inside of the cell with the tails facing in.