Content Summary:

The human body is complex and is constantly being studied. Scientists have found that the structure and physiology of the body is based on the interactions of atoms, ions and molecules. Understanding these interactions is the basis for this chapter. Learning about covalent, ionic and hydrogen bonds reinforces the knowledge of how complex the human body is.



Summary #1--Chemical elements comprise the makeup of the human body. The smallest unit is an atom and can only be viewed with an electron microscope. The nucleus is the center of the atom and contains protons, which have a positive charge, and neutrons which have no charge. The positive charge of the protons are offset by the negative charge of electrons which are outside the atom. An atom can bond with another atom in a number of different ways such as covalent, ionic and hydrogen bonds. A molecule is the result of bonding of two or more atoms.


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Summary #2--Carbohydrates are organic molecules made up of carbon, hydrogen and oxygen atoms. They are also called sugars and come in many forms such as monosaccharides, disaccharides and polysaccharides. Glucose,a monosaccharide, can form polysaccharides when bonded together and can form glycogen which is the human energy storage molecule. Thousands of glucoses can be stored in one polysaccharide molecule which provides for water conservation within cells.



Summary #3--Proteins are made up of long chains (bonds) of amino acids. There are approximately 20 different amino acids that can bond in various ways to build proteins. Amino acids can form peptide, dipeptide, tripeptide and polypeptide bonds. These can join with other molecules to form glycoproteins and lipoproteins. They can also be bonded with pigment molecules to make hemoglobin and cytochromes. Proteins can be structured in four different levels and each has it's purpose.



Application:

The chemical aspect of the human body proved to be more interesting than I thought. I have always believed that our chemical makeup was very complex, but after studying this section, it really hit home again. Learning that there are chemical reactions going on continuously within and that those reactions have a purpose made this chapter much more exciting. Even though I still do not understand all the concepts, I feel it is a privilege to learn about them. I have been thinking about the ways in which this chapter can apply to my career and blood pH comes to mind. I know that pH in the soil is important, but learning about blood pH and what can happen when that is not at neutral was an eyeopener for me. Thankfully our bodies have the built in negative feedback system which regulates any fluctuations. I am now more aware of two conditions--acidosis and alkalosis that could occur in patients I may treat. There are different types of each condition, and if I treat a diabetic patient, or one with renal disease, it is good to know that I should be alert to these possible conditions.



Essential Question:

Buffers are a group of molecules that react with acids or bases to prevent fluctuations in the pH of body fluids such as blood. Some common buffers are carbonic acid and bicarbonate which act as a buffer pair in blood plasma to help maintain a pH between 7.35 and 7.45. If the blood becomes too acidic, then bicarbonate is the buffer and neutralizes the acid. If the blood becomes too basic, then carbonic acid is the buffer and neutralizes the base. Acidosis is a relative increase in the acidity of the blood which means the blood has too many hydrogen ions. There are many types----carbon dioxide, compensated, hypercapnic, hyperchloremic, lactic, metabolic, renal and respiratory. Alkalosis is a relative increase in the alkalinity of the blood due to an accumlation of alkalines or a reduction of acids. There are also many types---altitude, compensated, hypochloremic, hypokalemic, metabolic and respiratory.

Enzymes are protein catalysts that increase the rate of chemical reactions. They have an important role in human physiology in that keep body functions moving at a pace that works to maintain homeostasis. Without enzymes, our body processes would occur too slowly and life could not be maintained. Enzymes bind to a molecule and weaken a chemical bond so that it will break faster and move the process on quicker. Enzymes are not altered in the reaction, so when the molecule and enzyme separate, the enzyme is free to catalyze another reaction.

References: Anatomy & Physiology by Stanley E Gunstream, Taber's Cyclopedic Medical Dictionary, and

http://en.wikipedia.org/wiki/Buffer_solution