Friday, January 25, 2013

Rat Dissecrtion:

          Last Thursday, our Biology class was fortunate enough to participate in a rat dissection. Upon arriving to class, we were divided up into groups of three or four where we discussed roles in our dissection. After a few minutes, all of the groups received their rats and we began examining its external features. Our group was given a female rat, but unfortunately, our rat was not pregnant at the time of death, so we were unable to see any rat  fetuses. Our group was able to analyze its whatever we could see to find out some information about the appearance of the rat. This was the first dissection that involved a a mammal rather than a squid or a worm. The rat's anatomy was completely different and it was much larger in comparison to the other organisms.

          As soon as we finished looking over all of the rat's features, our group hastily cut through the rat. Our group was able to make a clean precise horizontal cut across the rat's stomach area and then we made a long incision from the head to anus allowing us to finally open up the rat. After awhile of attempting to pin the rat's limbs down on the tray, we were finally able to take a look at its internals which was extremely fascinating. With the skin pinned down on the container, the first thing we noticed was a bright pink latex like substance resting upon the lung area, which showed the blood flow with deoxygenated blood and oxygenated blood. After examining the exterior of the internals, we probed the rat's mouth with a blunt tool and we managed to see it around its heart after we inserted it through the mouth. After taking close looks at the insides, it was time to break the ribs and look at the heart. Our group ended up cutting through the ribs with a razor blade when we were cutting through the skin, but fortunately, it did not damage the heart. The bones were able to be pulled apart with ease and we were left with the deceased rat's exposed heart in which we simply pulled out. I wish I had more time to examine it; however, it was time to pack up and I was unable to attend the next dissection because of the Holocaust speaker presentation.

          Through this dissection, I was able to learn a lot about the internal as well as external features of the rat and thanks to the diagrams that were provided, I was able to label the internals of the rat. With the questions that were completed, I learned a lot about what organs do and what specific parts of a rat does for it. For example, I learned that the tail is a major temperature modification system. I learned a bunch of miscellaneous facts about them too! In my opinion, this dissection was the most educational because I found it the most interesting. It was really neat to see the insides of a rat because since it is a mammal, it has a very similar internal structure as us. This dissection helped me understand what certain organs accomplish in the body and it was a arguably one of the best parts of Biology 11!

Discussion Questions :

1.) Why are your hands the best tools for dissection?
Your hands are the best tools for dissection because they are the most versatile. It is often difficult to control tools and with your hands, you get to examine and feel the part that you are touching.

2.) What is the purpose of having all different labels and titles for dissection?
The purpose for having different labels and titles are to distinguish which anatomical feature that you are specifically attempting to single out. With specialized labels, you are able to narrow down your labeling to certain features of the rat and it is easier to point out extremely precise parts of the rat.

3.) In what way did the tail differ from the rest of the body?
The tail felt hard and seemed to have a scale like texture to it. In comparison to the body, the rat's tail had relatively no fur on it.

4.) What purpose is served by the vibrissae?
The vibrissae are used to help the rat in tactile sensation, but there are no nerves located inside.

5.) Your specimen is bilaterally symmetrical. What does this mean?
Since the rat is bilaterally symmetrical, it has one line of symmetry.
As you can see, the rat has one line of symmetry.

6.) The Sphincter is described as a circular muscle. Why is it this shape and what does it do?
The sphincter is used to open and close to regulate the flow of food and its shape is circular because it fits the tube better which also has a circular shape.

7.) Why is there a difference in the size of the small and large intestine?
The small intestine is used to extract nutrients from the food and the large intestine is used to break down food.
The small intestine is located just under the kidneys which appear as oval-like stones.


8.) The liver is the largest organ in the body (after the integument. ) What is its function?
It produces essential enzymes for the intake of nutrients. The liver is used for the detoxification and production of chemicals necessary for digestion.
To the very right, the oval-like stones are the liver.

9.) How did the duodenum acquire its name?
The duodenum got its name because duodenum is Latin for twelve finger widths which is approximately twenty cm.

10.) What purpose is served by the appendix in those animals that retain it as a functional organ?
The appendix is used to breakdown cellulose. It helps harbor safe bacteria and its an extra place for them to be stored.

11.) In each of the cavities, there is a membrane that covers both the wall of the cavity and the organ it contains. What is the function of the membrane?
The membrane's function is to hold all of the organs in place. It keeps them from moving around too much.
The membrane is dried up, but it is in its internal cavity.

12.) What is the function of the spleen?
The function acts as part of the immune system and it produces or stores blood cells for the circulatory system.
The spleen is located along the left side of the picture.

13.) What is the function of the diaphragm?
The diaphragm has many functions, but its main functions are to help in respiration and breathing. The diaphragm helps air to exit to the lungs.
The diaphragm is located right beside the heart.

14.) What distinguishes the atria from the ventricles?
The atria hold the blood entering the heart and hold it until it passes onto the ventricles. The ventricles push the blood to where it needs to be.
The heart has the atria and ventricles. ( Where the pinkish substance is. )
15.) Why is the wall of the left ventricle thicker than that of the right?
The left ventricle is responsible for pumping oxygenated blood to the entire body. This means that the thicker wall enables it to have more power to push the blood, whereas the right ventricle only needs to reach the lungs,

16.) What are the similarities exist between male and female reproductive systems?
Both male and female reproductive systems are very different; however, one common thing that they share are their pituitary glands.

17.) What do kidneys do?
Kidneys are responsible for processing the blood to get rid of as much waste as possible. It collects the waste from the blood and sends it to be excreted.
I do not have a close up of the kidneys.

18.) In the dissection, you located the thyroid, the thymus, and the adrenal glands. To which system does this belong to? These structures are a part of the respiratory system,


P.S. I know there are not many photographs of the rat and there are definitely no specific photographs of the externals as well as the internals; however, I was not the person in charge with photographing this specimen and this was all that I was given to work with.

          For this last bit of my final blog, I would like to take this opportunity to thank you for teaching our class this semester. Throughout this course, I've learned so much about Biology which was an extremely fun experience. I would like to apologize on behalf of my ill-advised peers because they could be extremely rude or obnoxious during times in this semester and I wish you luck in the future and thanks again for teaching us!

1 comment:

  1. Great entry Jon!! Thank you for your kind words. It truly was a pleasure to teach you this semester!!
    Purpose 4/4
    Relate to class 4/4
    Reflection 4/4
    Writing 4/4
    Photos 0/6
    Questions 18/18
    34/40

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