As a nurse you will need to have a thorough understanding of the basic sciences including Biology, Chemistry and Physics as well as Mathematics. Many people understand the need to study Biology but many don't realise that Chemistry and Physics are also important. Nurses are in greater demand than ever and in the US alone it is expected that there will be a need for 1 million new registered nurses by the year 2020. The number of graduates needs to be increased by ninety percent to make sure there are enough nurses in the next few years. Nurses don't just work in hospitals but in many other areas including clinics, schools, in patients homes or in companies.

Why is Chemistry Important to Nursing?

If you want to thoroughly understand biology and the processes that occur in our bodies then you need an understanding of both chemistry and physics. All the processes that occur at the cellular level, such as the actions of enzymes and diffusion across cell membranes need an understanding of basic chemistry concepts. How is oxygen transported from the lungs to where it is needed? How is the pH of the blood balanced so that it doesn't become too acidic or basic? How is glucose metabolised and what goes wrong in patients with diabetes? All these questions and many, many more all need a good understanding of the basic concepts of chemistry.

How the Blood is Buffered

Let's start with an understanding of the way the blood pH is maintained. pH is the measure of how acid or alkaline a solution is. The pH scale is from 0 (acidic) to 14 (alkaline) and the blood pH must be maintained between 7.35 and 7.45 which is slightly basic. OK now we've already come across some terms you may be unfamiliar with. pH is defined as -log of the hydrogen ion concentration (the p stands for -log and the H for hydrogen ion concentration) and is usually written as pH = -log[H+]. So how acid or basic a solution is depends on the H+ concentration. Anything that releases hydrogen ions is called an acid and anything that accepts hydrogen ions is a base.
In the blood the pH is maintained by a buffer system which mainly uses a carbonic acid - bicarbonate equilibrium as shown in the equation below.

Buffers are important concepts in maintaining homeostasis in the body. They are defined as substances that prevent a change in pH with small additions of acid or base. Without a buffer system in the blood the pH would not be maintained in the narrow range that is needed, with dire consequences!
In this one example we have already used a whole range of chemical concepts including chemical formulae, hydrogen ions, acids and bases, equilibria, buffers and pH!

What else happens in the blood?

One of the most important functions of the blood is to carry oxygen from the lungs around the body and return carbon dioxide to the lungs to be excreted. How is this accomplished? Red blood cells contain hemoglobin which is a protein with a complicated structure as shown in the diagram below.

Hemoglobin Molecule

The most important part of the hemoglobin molecule, as far as blood gas exchange is concerned, is the part containing an iron atom(Fe). The iron atom is at the centre of a ring containing nitrogen atom as you can see in the image below. In the lungs oxygen attaches itself to the iron and carbon dioxide is released. In other parts of the body the reverse effect occurs.

How is this possible? Well we have to bring in some physics here! (Didn't I say nurses also need to understand some basic physics!)

The curve shows you how the oxygen saturation of the hemoglobin molecule is related to the partial pressure of the oxygen in the blood. Partial pressure is defined as 'The pressure exerted by each of the constituents of a mixture of gases'. When the partial pressure of oxygen is high as it is in the lungs, the oxygen becomes bound to the hemoglobin. When the blood reaches the tissues where the partial pressure of oxygen is much less the oxygen is released. 

The sodium potassium pump

All cells in the body are high in potassium ions, K and low in sodium ions, Na. To keep this balance in place is a mechanism called the sodium/potassium pump. It is necessary to move sodium ions out of the cells and potassium ions into the cells across a plasma membrane.

What exactly are sodium and potassium ions?

OK before you read the next bit it might be a good idea to have a look at a periodic table below (You can see bigger image by clicking on the picture). All the elements are arranged in order of their atomic number. This is the number of protons in the nucleus of the atom with hydrogen, the lightest element having one proton and the the heaviest known element 118. Scientist have just discovered the element with atomic no 117! It's so new it isn't on any periodic tables yet. Find out about its discovery here http://www.nytimes.com/2010/04/07/science/07element.html

The Periodic Table

Hmm - well back to rather less exotic elements sodium an potassium! Now sodium has 11 protons in its nucleus (which are positively charged) balanced by 11 electrons (which are negatively charge) so overall it's a neutral atom. When sodium reacts it gives up one of these electrons as it's more stable that way and now has 11 positive protons and ten negative electrons so it now has an overall positive charge. We call it an ion (thats an atom or group of atoms with a negative or positive charge). Potassium behaves in the same way. So cells need to have more of the potassium ions and less of the sodium ions. Now in normal diffusion a substance will move from a high concentration to a lower concentration but in the sodium potassium pump the sodium is being moved from a low concentration to a higher concentration. Potassium is diffusing from a low concentration to a high concentration, the opposite. This requires energy which is suppled by the substance known as adenosine triphosphate (ATP). A diagram of ATP is shown below.

An ATP Molecule

Glucose Metabolism

Glucose is a vital molecule that is made by plants in a process known as photosynthesis and is consumed by us in our food. It provides us with energy but if you have diabetes you will not be able to remove glucose from the blood. As the concentration of glucose increases after a meal insulin is produced by the pancreas which removes the glucose from the blood and takes it to the cells that need it for energy. In diabetes the body does not produce enough insulin so that the level of glucose in the blood remains high. A glucose tolerance test is used to diagnose diabetes. The patient fasts overnight and then drinks a glucose containing liquid. Blood test and sometimes urine tests are taken over the next two hours to see how the body reacts to the spike in glucose in the blood. Here's a diagram of the glucose molecule. It's what is known as a carbohydrate and is a ring of 5 carbon atoms and an oxygen atom.

A Glucose Molecule
 

These are just a few of the processes occurring in living systems and, as you can see, we've covered quite a bit of chemistry and some physics to understand the biological changes. I hope this has made it clear that you can't gain a good understanding of biology without a good background in the basics of chemistry and physics and why chemistry is important to nurses. To be a good nurse requires a thorough understanding of all aspects of science.