Virtual lab 5 worksheet mice dissection PDF

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Virtual Lab 5

Mice dissection

Introduction The mouse is an important model organism for studying human diseases. In this virtual lab, students will learn the proper handling of a live mouse, conduct carbon dioxide asphyxiation to sacrifice the mouse and learn skills and procedures of a typical mouse dissection. Students will then systematically identify the organs in the digestive, respiratory, cardiovascular, and reproductive systems as well as other accessory organs in the dissected mouse. Finally, students will discuss the function of the identified organs and make connections with the anatomy and physiology of the human body Materials Disposable gloves, dissecting instruments, tray, mice, twine, bone cutters, paper, scalpels, plastic bags, and string Activity I Performing CO2 asphyxiation on mouse 1. Choose your mouse and catch it by the tail 2. Drop the mouse into a glass beaker and cover the mouse completely with a funnel connected to a CO2 source 3. Treat the mouse with CO2 until it stops moving Videos to watch – mouse dissection part 1

Activity II Performing mouse dissection 1. Lay your mouse on the dissecting stage with its back side facing the surface of the tray 2. Stretch the legs of the mouse one at a time and pin them to the stage that cushions the mouse 3. Splay the legs outwards to keep them out of the way while cutting through the abdominal and chest cavity 4. Start by making an incision at the bottom of the belly and use the sharp end of the scissors to separate the underlying connective tissues from the epidermal layer Videos to watch – mouse dissection part 2

5.

Once the epidermal layer has been separated and properly secured on the stage, make another incision at the bottom of the belly and carefully remove the semi-transparent connective tissues to reveal the body cavity and the organs inside

6.

Be careful not to puncture or damage any organs and blood vessels Videos to watch – mouse dissection part 3

7.

Locate the liver which is the large portion underneath the heart

Q1

What chemical does the liver and gallbladder secrete into the duodenum? And what is the function of this chemical in food digestion? (2 points)

Q2

What are the functions of the liver? (5 points)

8.

Lift the lobes of the liver on the left side of the mouse, locate the large, pale, sac-like structure which is the stomach

Q3

What are the functions of the stomach? (2 point)

9.

Lift the lobes of the liver, locate the small, oval, and red structure spleen and cashew shaped structure kidney

Q4

What are the functions of the spleen and kidney? (2 points)

10. Small intestines. Locate Duodenum, Jejunum, and Ileum. 11. Large intestines (colon): locate Cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum. 12. Force air through the mouth of the mouse using a 1mL pipette Videos to watch – mouse dissection part 4

Q5

How many tracts run through the neck? (2 points)

Q6

From the video, which organ was inflated? And why? (2 points)

Q7

Identify parts of digestive system (13 points)

Parts Liver Stomach Spleen Kidney Duodenum Jejunum Ileum Cecum Ascending colon Transverse colon Descending colon Sigmoid colon Rectum

Did you find it? (Yes/No)

Videos to watch – mouse dissection part 5

13. Locate the large dark liver, which covers much of the upper abdominal cavity. Lift the lobes of the liver on the right side of the mouse and locate the small, greenish sack like gallbladder. 14. Lift the lobes of the livers on the mouse’s left side, and locate the large, pale, saclike stomach

Internal anatomy of rat

Small and large intestines of human

15. Follow the stomach toward the right side of the mouse as it tapers down to join the duodenum (the first part of the small intestine). Then follow the duodenum to where it hooks back to the left of the mouse. This is the start of the Jejunum. Continue to follow the small intestine until it attaches to the large intestine. The latter half of the small intestine, which attaches to the large intestine, is the ileum. Because the jejunum and ileum are coiled together and difficult to differentiate, most sources refer to them collectively as the jejuno-ileum in the mouse. Q10 What are the functions of the small intestine? (2 points)

Q11 Why do you suppose that the small intestine is the single longest portion of the digestive tract? (2 points)

Q12 At the junction of the large and small intestines, you should see a small thumb-like pouch called the cecum which is more obvious in the mouse than in humans. What is the function of the cecum? (1 point)

Q13 What are the functions of the colon? (2 points)

Q14 What is the name of the opening to the outside of the body where feces are excreted? (1 point)

Q15 What are the typical components of the human feces? (2 points)

Activity III Additional questions Q16 What makes mouse an excellent model organism to study human disease? (2 points)

Q17 Which structure separates the thoracic and abdominal cavities? (1 point)

Q18 Where can you find the pancreas? What is the function of this organ in the digestive system? (2 points)

Q19 What are the contents of the pancreatic juice? (2 points)

Q20 What is the largest organ in the mouse? (1 point)

Q21 Which organ stores urine and which organ forms urine? (2 points)

Q22 What are unborn mice called? (1 point)

Q23 Are mice herbivores, carnivores, or omnivores? Explain why (2 points)

Q24 What is another name for the chest region of the mouse? (1 point)

Q25 What is another name for the belly region of the mouse? (1 point)...