Rat Dissection!

     On Thursday, January 17 and Friday, January 18, our Biology class dissected a Rat! Yes, those disgusting rodents that almost every person loathes *yuck. I missed Friday's class, but I was still able to see the rat get cut open on Thursday, and it looked both fascinating and disgusting at the same time. The purpose of this dissection was to learn about the anatomy of the rat, both inside and out. The rats were preserved, so there was no presence of blood (thankfully). Before this lab, we learned about the different classes of vertebrate animals within the Phylum Chordata living on our planet. These different classes include Class Amphibia (Amphibians), Class Agnatha (Jawless Fish), Class Chondrichthyes (Cartilagenous Fish), Class Osteichthyes (Bony Fish), Class Reptilia (Reptiles), Class Aves (Birds) and finally Class Mammalia (Mammals). After learning more about all the different classes of animals, I couldn't wait to delve into this rat dissection.


     We started this dissection by observing the external anatomy of the rat and checking its gender first. Our rat was a male since it had a pair of testes. Since this rat was preserved, it was pretty stiff, especially its tail. After quickly observing the external anatomy of the rat, it was time to finally cut it open! Since there was an open slit near its neck, we decided to start there for a nice and clean cut through. After precise cutting, we were able to open up the rat. Upon opening the rat, a number of organs were within our sights, including both the small and large intestines, the lungs, the liver, the stomach and many more organs. After observing all these organs, my group decided to pull out the intestines, and soon afterwards, the heart. I was not there physically to be able to observe the intestines or the heart being pulled out, but judging from the pictures, I could tell it wasn't an easy job. Overall, this dissection was a fascinating experience and out of all the dissections that I've taken part of in this class, this one would have to be the most fulfilling one yet.  



   

1) Why are your hands the best tools in dissection?
Your hands are the best tools in dissection simply because we use them everyday . We also get a hands on experience for the betterment of our learning and hands on experience. 

2) What is the purpose of having all the different labels and titles for the dissection?

The purpose of having all the different labels and titles for the dissection so its easy to organize and identify each structure.

3) In what way does the tail differ from the rest of the body?
The tail differs from the body since it has no specific function.  

4) What purpose is served by the vibrissae?
The purpose of the vibrissae is to help the rat take in its surroundings. 

5)Your specimen is bilaterally symmetrical. What does this mean?
Being bilaterally symmetrical means that if the specimen is cut in half, the two sides would mirror each other. 

6) The Sphincter is described as a circular muscle. Why is it this shape and what does it do?

The Sphincter is in the shape of a circle and it lets food through.

7) Why is there a difference in size between the small and large intestine?
There is a size difference in the intestines so that large intestine breaks down the food and the small intestine breaks down and spreads out the nutrients.

8) The liver is the largest organ in the body. What is its function?
The liver clears out any poisonous substances within the body and purifies and deoxifies  oxygen.

9) How did the duodenum acquire its name?
The duodenum was given its latin name because of its 12 fingerbreadths  long (25 cm) meaning, which is what the meaning of duodenum implies. 

10)  What is the purpose of the appendix in animals who retained this as a functional organ?The appendix aids in digesting tough foods since it contains special digestive enzymes.

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 keeps all fluids within the body so that there are no accidental leaking from the body.

12) What is the function of the spleen?
It discards old red blood cells and stores in it healthy, white blood cells.

13) What is the function of the diaphragm?

The function of the diaphragm is to aid in breathing and respiration by contracting and expanding.

14) What distinguishes the atria from the ventricles?

The atria pumps blood to the ventricle while the ventricle pumps blood to the rest of the body.

15) Why is the wall of the left ventricle thicker than that of the right?

The left ventricle is responsible for pumping blood to the rest of the body while the right ventricle is only  responsible for the lungs.

16) What are the similarities exist between male and female reproductive systems?

The male and female reproductive systems are very different, and the only similar thing they share is the pituitary gland.

17.) What do kidneys do?

Kidneys are used for getting rid of waste by processing blood through it. The kidney collects the wasted from the blood and then it is excreted from the body.

18.) In the dissection, you located the thyroid, the thymus, and the adrenal glands. To which system does this belong to?

The thyroid, the thymus and the adrenal glands belong to the respiratory system.