Mini 3

We had out third mini exam today.  I felt that it went well, it definitely seemed to be the easiest of the three so far.  Last semester this exam was my worst exam, i scored in the bottom 3% for the class, so hopefully this exam goes much better.

After the exam, a few friends and I went to Kathyrne's to eat, I had my first quality burger on the island!  I wanted to rest, but there was a black scrub session, which is when the anatomy professors and lab TA's clear up any lab practical questions, and these sessions are far and few between.  It was very helpful, as one of the professors quizzed a group of us and demonstrated different features of the abdominal cavity such as the branches off the abdominal aorta.  The anatomy practical is on Monday.  Then I took a nap, cooked, previewed some material for the upcoming week, and watched youtube videos.

I found the fetal heart development and blood supply to be the most interesting material from this block, which included: gastrointestinal anatomy, epithelium, connective tissue, lung anatomy, and nervous tissue.  It is interesting to see the heart develop from such a tiny tube.

The major concept we leared about the blood flow to the fetus were the three shunt systems: ductus venosus, ductus arteriosus and foramen ovale.  The ductus venosus allows the umbilical vein from teh mother to bypass the fetal liver while still providing blood for the development of the liver.  The ductus arteriosus connects the pulmonary artery to the aorta.  Generally the pulmonary artery will bring oxytgenated blood to the lungs, but in the fetus, the lungs are filled with fluid, increasing the resistance.  Therefore, the blood that would be going to the lungs, gets shunted to the aorta to be distributed throughout the body, as the blood is mostly oxygenated (coming directly from the mom's placenta).

After the baby is born, these shunts are closed due to the lack of prostagalandins, which are distributed by the mother through the umbilical vein.  However, after the umbilical
vessels are removed, prostaglandins are no longer distributed leading to a closing of the shunts, essential to the development of the functional circulatory system.  The image below shows an abnormality called "patent ductus arteriosus" which leads to a mixing of oxygenated and deoxygenated blood.  This can be  fairly easily resolved by surgery.