Your left lung it’s a hero, it sacrifices space so that your heart can be somewhere in your body. That space is called the “cardiac notch” which makes the left lung smaller than the right lung.
The cardiac notch is the lateral deflection of the anterior border of the left lung. It is produced to accommodate the space taken up by the heart.
That is also not the only difference, it also has two lobes compare to three lobes. Together, the lungs contain approximately 2,400 kilometres (1,500 mi) of airways.
Know more about lungs and lung cancer:
http://www.mdanderson.org/patient-and-cancer-information/cancer-information/cancer-types/lung-cancer/index.html
#humananatomy #lungs #cardiacnotch #medicine
So why didn't the heart move to the center? Stupid evolution! It just can't get it right the first time. :-)
ReplyDeleteMatt B Corina Marinescu could answer this question better than I. I'm going to give it a go of what I know. I study animals not humans. I'll let her follow up to correct me or fill in the blanks. :-)
ReplyDeleteWhen we look back to the fossil record. The one heart, two lungs system began to emerge about 300 million years ago, when animals first moved from sea to land. From that point on, it's been the norm and it's a system it's not unique to humans. The organ systems we find in most animals contain one heart and two lungs. That is, with the exception of earthworms and cephalopods -- the invertebrate class which includes octopuses and squid. Earthworms have five heart-like structures. Cephalopods have three hearts (two to send blood to the gills, and one to send blood to the rest of the body) and no lungs. Interestingly, when we are in the embryonic stage of development, we actually do have two hearts. The heart primordia (which describes the stage of the heart's development) in the embryonic stage is actually two hearts, which eventually fuse together into one heart with four chambers. We only have one heart because system is already functioning at full bore, the addition of an extra heart wouldn't do much.
Well I guess one can say anything here and never expect anyone to fact check ones claims. The heart is in fact near the center of the chest. Even if you are not a surgeon like Corina, you would know from CPR class that the heart lies just slightly left from your sternum from your perspective. So the heart is in the center of the chest. Yes the left lung is slightly smaller than the right. View photo:
ReplyDeletehttp://s.hswstatic.com/gif/two-lungs-one-heart-1.jpg