2012 Final

Well, where do I even begin? This semester in Biology, I have honestly learned A LOT! I am going to explain 4 body systems that we learned about in class this semester in great detail, and I hope you enjoy!


First of all, i'm going to start out with the Muscular System! We have learned about the muscular system a lot this semester, and it is one of the few that I can explain well. The muscular system is made up of tissues that work with the skeletal system to control movement of the body. Some muscles, are voluntary, meaning that you decide when to move them. Other muscles, like the ones in your stomach, heart, intestines and other organs, are involuntary. This means that they are controlled automatically by the nervous system and hormones and you often don't even realize they're at work!


Secondly, is the Immune System. The immune system is our body's defense system against infections and diseases. Organs, tissues, cells, and cell products work together to respond to dangerous organisms (like viruses or bacteria) and substances that may enter the body from the environment. There are three types of response systems in the immune system. The anatomic response, inflammatory response, and the immune response. The anatomic response physically prevents threatening substances from entering your body. Examples of the anatomic system include the mucous membranes and the skin. The inflammatory system works by excreting the invaders from your body. Sneezing, runny noses, and fever are examples of the inflammatory system at work. When the inflammatory response fails, the immune response goes to work. This is the central part of the immune system and is made up of white blood cells, which fight off infection by gobbling up antigens. 


Then, is the Circulatory system. The circulatory system is the body's transport system. It is made up of a group of organs that transport blood throughout the body. The heart pumps the blood and the arteries and veins transport it. Oxygen-rich blood leaves the left side of the heart and enters the biggest artery, called the aorta. The aorta branches into smaller arteries, which then branch into even smaller vessels that travel all over the body. When blood enters the smallest blood vessels, which are called capillaries, and are found in body tissue, it gives nutrients and oxygen to the cells and takes in carbon dioxide, water, and waste. The blood, which no longer contains oxygen and nutrients, then goes back to the heart through veins. Veins carry waste products away from cells and bring blood back to the heart , which pumps it to the lungs to pick up oxygen and eliminate waste carbon dioxide.


Finally, i'm going to explain the Digestive System. The digestive system is made up of organs that break down food into protein, vitamins, minerals, carbohydrates, and fats, which the body needs for energy, growth, and repair. After food is chewed and swallowed, it goes down the esophagus and enters the stomach, where it is further broken down by powerful stomach acids. From the stomach the food travels into the small intestine. This is where your food is broken down into nutrients that can enter the bloodstream through tiny hair-like projections. The excess food that the body doesn't need or can't digest is turned into waste and is eliminated from the body.


To conclude, I have explained the muscular system, the immune system, the circulatory system, and the digestive system! These are all things that we have learned in biology this semester. I have really enjoyed having class with Mrs. Dent, and i'm going to miss her!