Unit 5 Reflection: The Digestive, Endocrine, and Lymphatic Systems

In this unit, we learned about the digestive, endocrine, and lymphatic systems. The essential questions for this unit were:

• How are the functions of the digestive system fulfilled by the structures of the alimentary canal and accessory digestive organs?
• How does the body use certain molecules and biochemical pathways to meet its energy demands?
• How is diabetes a disruption in fuel metabolism?
• How do glands use hormones to control various activities of the body?
• What is the role of the lymphatic structures in the body's defenses and circulation?

The digestive system consists of the alimentary canal (also known as the gastrointestinal track), a long, coiled tube that runs through the body and is open at both ends, and the accessory organs to the alimnetary canal. The organs of the alimentary canal are, in order, the mouth, pharynx, esophagus, stomach, small intestine, large intestine, anal canal, and anus. These organs either digest (break down) food or absorb (take in) nutrients from the food. Assisting them are the liver, gallbladder, and pancreas, which make and store enzyme that help with digestion.

the digestive system (Wikipedia)

The endocrine system is the system of glands in the body that release hormones that affect the body. Hormones can be steroid (lipid-soluble) or non-steroid (non-lipid-soluble) and act like "keys" to "unlock" a certain result or action from a cell. The many glands of the endocrine system include the pituitary, thyroid, parathyroid, and adrenal glands and the pancreas. Each one releases one or more different hormones that regulate different parts of the body.

the endocrine system (Wikipedia)

The lymphatic system is a system of vessels that run parallel to the circulatory system's blood vessels and contain a plasma-like fluid call lymph. This lymph comes from liquid lost by the circulatory system or from tissues, and the lymphatic system's job is to return it to the circulatory system. The lymphatic system is also very closely related to the immune system, as there are areas where lymph vessels congregate, called lymph nodes, which host a huge number of immune cells, ready to attack any foreign invader that might be in the lymph. The lymphatic system also includes the thymus, tonsils, and spleen, which are also involved in the immune response.

the lymphatic system (Wikipedia)

One of the themes of this unit is balance. One of the systems we learned about, the endocrine system, is especially all about balance. It makes sure that there is enough of each hormone in the bloodstream at any given time so that homeostasis is properly maintained. The hormones released by the glands of the endocrine system can regulate fluid retention, metabolism, protein synthesis, mineral levels in the skeletal system, heart rate, blood pressure, respiration, and many more. If this delicate hormone balance is upset, it can spell disaster for the body. In this unit we also learned about diabetes, which occurs when the body cannot properly regulate the level of glucose in the bloodstream. This may be because the body cannot produce insulin (type I diabetes) or because the body stops responding to insulin (type II diabetes).

During this unit, we did one lab, the digestive system lab. I thought the lab was very interesting, since it let me see firsthand just how long the digestive system really is. I had always known that the digestive system is very long in the way that one knows a strand of DNA is long, but doesn't actually realize it until one holds it in one's hand.

I would have loved to learn more about the lymphatic system, which most people don't know much about. I am also interested in the different hormones of the endocrine system and how exactly they affect different parts of the body.

At the beginning of this semester I set some New Year's goals, which were to get more sleep and to study for exams earlier. So far, I have gotten more sleep but not as much as I had wanted to (8 hours). However, I am reviewing the material I have learned every day, accomplishing my second goal. I will continue to work on my first goal and hopefully reach it by the deadline I set for myself (February).

2016.01.05 Digestive System Lab

Today, we made a measured the length of our digestive system. The main organs of the digestive system are the mouth, the esophagus, the stomach, and the small and large intestines. We used different colors of ribbon to represent each organ in the digestive system. I chose blue ribbon to represent the mouth, green to represent the esophagus, pink to represent the stomach, white string to represent the small intestine, and red to represent the large intestine. Then I tied all the pieces together, resulting in a very long string, representing the length of my digestive system.

lengths and color of strings I used

all the string I used

The length of my digestive system turned out to be 8.336 meters. In comparison, my height is 1.524 meters, which means that my digestive system is almost 6 times my height. In order to fit such a long organ system in my body, it must be folded over and over again (especially the small intestine, which is the longest organ in the digestive system).

I though that it takes about 2 days for food to move through the entire digestive system. After searching online, I found that it takes a little less than 2 days (30-40 hours) for food to move through the entire digestive system, which is pretty close. Factors such as the composition of the food, gender, and stress levels all can affect the amount of time it takes for food to move through the digestive tract.

Digestion is the breaking down of food into little pieces (nutrients), while absorption is the taking in of these nutrients by the body. Digestion occurs in the mouth and stomach, while it is the intestines that absorb nutrients from the digested food.

New Year's Goals

I have set some goals for 2016:

• I will get at least 8 hours of sleep everyday. To do this, I will manage my time better, such as by allocating a specific amount of time for everything I do, so that I do not waste any time and have more time to sleep. I will achieve this goal within by February.
• I will start studying for tests earlier. After every class, I will review what I have just learned, instead of just studying for tests the night before. This will allow me to retain information better, as well as give me less exam-related stress. Next time I have an exam, I won't be cramming, and I won't be losing any sleep by staying up later to study for a test.