Rat Dissection

On January 17 and 18, our Bio class did a two part rat dissection which was like any other dissection but with a little bit more guts. Once we got back from winter break we began to learn about vertebrates from reptiles, amphibians, birds etc. When we finally saw all the rats in the tub, I was expecting an odor of some sort and fresh looking rats but what we saw was faaar from being fresh because it was preserved and looked like 'Asian' rats. Any who,  at first everyone was squirming around as usual but being around it for a while got us warmed up and very hands on, it turned into a four person job instead of just two which got very messy, Nick got rat juice got into his eye that maybe goggles should be worn, well at least for Nick. The tools we used was a razor blade, pins, our hands, and some tweezers, but before we could do anything we answered simple questions and labelled the diagrams. First we looked at the external anatomy of the rat, poked around and have a closer look then we began to cut open the rat to see the internal anatomy. It was like looking into a little human but less complicated, but it was fun because we never know what we're going to get while dissecting. Like any other dissection, here are some questions we were to answer and pictures Milika took! 

Why are your hands the best tools for dissection?

Your hands are the best tools for dissection because we used them on a daily basis and know how to pull and poke around with easier.

What is the purpose of having all the different labels and titles for the dissection?
The purpose of having all the labels is for us to have a better understanding of whatever we're looking at, and the titles is what helps to identify which is which.

In what way does the tail differ from the rest of the body? 
The tail differs from the rest of the body because it doesn't do much besides stabilize balance for when they climb though they already have 4 legs to walk on.

What purpose is served by the vibrissae?
The purpose of the vibrissae is to navigate and feel vibrations and air speeds/current. It helps to avoid most of danger.

 Your specimen is Bilaterally Symmetrical. What does this mean?
Bilaterally symmetrical means having both sides of the body will have the same features, but in opposite directions. 

The sphincter is described as a circular muscle. Why is it this shape and what does it do?
The sphincter helps the release and entrance of liquids throughout the body, also to help give out maximum efficiency.

Why is there a difference in size between the small and large intestine?
Small intestine helps with digestion and absorption of food. The large intestine helps in re-absorption of food and eliminates waste.

The liver is the largest organ in the body. What are its function?
The liver helps to clear the blood of drugs and other substances, it creates bile, deoxifies and purifies the oxygen.

How did the duodenum get it's name?
The duodenum was given its name in latin because it is usually 12 finger breadths long and about 25 cm.

What is the purpose of the appendix in animals who retained this as a functional organ?
The appendix has a lot of digestive enzymes in it, and helps with the breaking down of tough-to-digest foods that animals eat. 

In each of the cavities, there is a membrane that cover both the wall of the cavity and the organ it contains. What is the function of the membrane?
helps to keep all the fluids inside, working efficiently, and makes sure that the fluids don't accidenlty leave the cavity somehow.

What us the function of the spleen?
The spleen removes old red blood cells from the blood, supplies and stores white blood cells, which produce anitbodies.

What is the function of the diaphragm?
The diaphragm controls the flow of air into the lungsl, helps the respiration system. Without it we can't breathe for it contracts, moves down to  inhale and goes upward and expands to exhale.

What distinguishes the atria from the ventricles?
The atria are smaller than the ventricles. Atria consists of thinner muscle tissue than the lower positioned ventricles and  pumps blood to the ventricles. The ventricles distribute blood around the entire body.

Why is the wall of the left ventricle thicker than that of the right?
The left ventricle is thicker than the right because it needs to pump blood through the entire body while the right ventricle pumps to the lungs to oxygenate the blood. 


What similarities exist between the male and female reproductive system?
The anatomy of the vulva is related to the anatomy of the male genitalia and the clitoral glans are also homologous to the glans penis in males.

What do the kidneys do?
Kidneys filter out wastes to be excreted in the urine, but their main purpose is to separate mineral salts, toxins, and other waste products from the blood, also conserves water, salts, and electrolytes.

In the dissection, you located the thyroid, the thymus, and the adrenal glands. To which system do they belong, and what do they do ?
The thyroid, thymus and adrenal glands are a part of the lymphatic and endocrine organ system. The role of the thyroid is to stimulate metabolism, and control the body’s circulating calcium levels. The Thymus gland is to chemically identify specific foreign invaders. The Adrenal Glands are responsible for producing cortisol and aldosterone.