The disorder where gastric juices creep back up the esophagus through the cardiac sphincter is called a reflux disease. This is a disorder that involves the incomplete closing of the cardiac sphincter and damage to the lining of the esophagus. I am sure you have seen the TV commercials of nexeum which is just one of the many medications used to fight gas the juices of the stomach from damaging the esophagus.

There is also a diorder where the opening in the diaphragm enlarging, allowing the esophagus to buldge or the stomach moving upward into the chest called a hiatal hernia.

Once the bolus moves into the stomach it is then broken down into a semisolid mixture by the stomach which is called chyme. I’ll go into more about what the stomach does next in the following article. Check back tomorrow.

Internal respiration on the other hand, is when gases are exchanged between the bloodstream and the cells throughout the body. Also known as cellular respiration, cells use the exchange of gases for their metabolism and produce energy with this fuel source.

The two phases of respiration are inhalation and exhalation, both of these phases are achieved by use of muscle contractions of the diaphragm and internal intercostals. The other muscles that are used in respiration are the scalenes and abdominal muscles.

Normal inspiration is achieved when the diaphragm muscle is contracted which leaves a void and causes air to be sucked into the lungs and surrounding windpipes. Normal expiration is achieved when the diaphragm muscle relaxes and the positive pressure forces the air out through the nose or mouth.  This normal act of breathing is also called tidal volume. The largest amounts of air that we can breathe in and out in one expiration is called vital capacity.  Inside the brain there are two parts of the brain that affect normal breathing because if is an automotic function and voluntary function are the medulla and pons. The two most important control centers in the medulla are the inspiratory and expiratory portions.  Eupnea is also a medial term for normal respiration rate.  

Diffusion is the process when gas moved from a higher concentration to a lower concentration this is how the smallest of units in the lungs exchange the gases in the lungs. A device was constructed to measure the amount of air exchanged in breathing it is called a spirometer.

When someone is breathing rapid and deep they are said to be hyperventilating, and the opposite which is slow and shallow breathing is called hypoventilating. If someone is experiencing labored or difficult breathing it is often associated with hypoventilation and is called dyspnea.  If someone stops breathing completely for a brief period of time is is called apnea. Some people suffer from sleep apnea. Which is simple that this occurs during sleep, apnea can also cause the person to loose consciousness as well.

Just like cardiac arrest you have respiratory arrest, this is when someone has failed to resume breathing after a prolonged period of time. Death can result if CPR is not administered immediately. The brain can only go for a matter of seconds without a fresh supply of oxygenated blood.

Covering the outer surface of the lungs is a membrane which was given a specialized name called the visceral pleura which covers the out surface of the lungs and lines the inner surface of the rib cage. This allows the lungs to freely inflate and deflate as respiration occurs. The pleural is then broken down into two diferent types they are the visceral and pariental membranes. More of the membranes will be covered in the next article.