Lungs and Heart, Thymus and Thyroid

This week, we took apart some of the organs that we dissected in a block last week.  First, we examined the trachea and esophagus.  They were two tubes at the top, the trachea firm and the esophagus soft.  We tried blowing into the trachea to inflate the lungs, but it didn't work.  Later, we used the eye droppers to inflate the lungs, and that was pretty cool!

Here on the right is a photo of what the organs we looked at this week would look like if we were very skilled dissectors.  The organs did pretty much look like this, but we generally had more damaged and missing pieces, because we are not yet very skilled at this dissection.  That's ok, we're just learning!

On the sides of the trachea, we all tried to find the thymus, which is an immune organ.  Most could find it.  It turns out the thymus is proportionately larger in a fetus compared to an adult.  See this picture to the left, and you see that in a fetus, the thymus is almost as big as a lobe of the lung, but in the adult, the thymus looks about a tenth the size of a lobe of the lung.

Then, we looked for the thyroid gland, which was a small, brownish organ also above the heart and near the trachea.  Most of us could not find that, probably due to not properly dissecting it out with the other organs.

We weighed each of the organs we dissected out today, which included the thymus, thyroid, lungs, and heart.  Each one was about 20 grams.  We also measured each of these organs with our rulers and noted all the measurements for our autopsy reports.

We discussed the lungs a bit, and wondered if it was possible to pop the lungs.  I thought that a normal human or animal could not pop their lungs simply by taking in a huge breath.  The lungs are designed to handle any size breath you can do.  But by blowing from an outside source (using the straws or medicine droppers to push air into the lungs) you could possibly pop them.  Also, some people get lung diseases when they are older that can cause their lungs to get brittle and the tiny air sacs can in fact pop.  Here is a picture showing how the airways get smaller and smaller in the lungs down to tiny little air sacs, called alveoli.  The largest tube is called the trachea, then there are two bronchi that come off.  Smaller than that is the bronchioles.  The diaphragm at the bottom moves down to cause the lungs to fill and up to make us breathe out and empty the air out of the lungs.  We need to discuss lung diseases such as asthma, smoker's lung, emphysema, lung cancer, pulmonary embolism, and bronchitis in class.  We also looked a bit at the hearts but need to discuss more about how the heart works.