Frog Dissection
Rules 1. Do not use any of the sinks! 2. Do not leave your seats once dissection begins. 3. Do not run, play or roughhouse! 4. Be extremely careful with the tools. 5. Do not ask to go to the bathroom. 6. Do not skip ahead. This is not a race!
Rules 7. Be sure all tools are in the case! Do not throw them away. 8. We do not leave until everything is clean! 9. Do not keep any body parts. Throw everything away!
Rules 10. Do not make any cuts until I tell you to do so! 11. If you are squeamish with the animals, don’t partner with someone that is squeamish! Failure to follow these rules will result in a ZERO for today’s lab!
External Anatomy
Frog The purpose of this dissection is to learn about the anatomy of the frog and how different parts of the anatomy function.
External Anatomy Examine the external anatomy of the frog locating the following parts: Tympanum, eyes, webbed feet, skin, tongue and teeth.
Tympanic Membrane – eardrum around membrane just behind the eyes. Head Region Tympanic Membrane – eardrum around membrane just behind the eyes.
Maxillary Teeth– Found on the upper jaw Mouth Observe the tongue Maxillary Teeth– Found on the upper jaw Vomerine Teeth– Found in the front of the mouth near the center.
Internal Anatomy
Let’s Begin 1. Turn the frog over on its back with the head away from you. 2. Cut off both arms using your scissors. 3. Using your forceps, lift the skin of the belly and make a slit with your scissors. 4. Now cut upwards towards the mouth of the frog.
4. Look at the following picture and make the same cuts. 5. Cut off the resulting flaps of skin.
6. Notice the smooth muscle beneath the skin. 7. Now repeat the procedure, this time cutting through the muscle. Be careful not to cut into the internal organs.
8. You may notice a yellowish tissue with long finger like lobes 8. You may notice a yellowish tissue with long finger like lobes. This is called fat bodies. Remove them with your forceps. (Our frog did not have fat bodies)
Digestion We will now find the following: mouth, liver, stomach, intestines, cloaca, pancreas.
9. Notice the liver, which is a brownish organ with three lobes. 10. Lift the liver and observe the greenish sac beneath. This is called the gall bladder. 11. Using your scissors cut and remove the liver.
12. Observe the stomach. Notice it is attached to the intestines 12. Observe the stomach. Notice it is attached to the intestines. Uncoil the intestines. See picture on next slide.
Cut here
13. Completely remove the stomach using the scissors. 14. Now you will cut open the stomach to observe what the frog ate. See picture on next slide.
16. Remove the heart using your scissors. Circulatory System 15. Make a cut with your scissors through the frog’s chest. Using your hands, break open the chest to expose the heart. 16. Remove the heart using your scissors.
Respiration 19. Observe the lungs. They lie right below the heart. Cut and remove the lungs.
Excretion 20. Kidneys – Two flattened organs lying on the back side of the body cavity. 21. Cut and remove them.
22. Notice the backbone of the frog. Muscles and Skeleton 22. Notice the backbone of the frog.
23. Remove the skin from the upper part of the hind leg 23. Remove the skin from the upper part of the hind leg. Note the muscles.
Lab Questions 1. What is a Tympanic Membrane? 2. Where are the Maxillary teeth located? 3. Where are the Vomerine teeth located? 4. What are the yellowish tissue with long fingerlike lobes? 5. What is the brownish organ with 3 lobes?
Lab Questions (Continued) 6. Where are the lungs located? 7. Where are the kidneys located? 8. Where is the gallbladder located? 9. What are the organs of the frog’s digestive system? 10. What long organ is attached just below the stomach?
Conclusion Questions- Answer in complete sentences, in paragraph form 1. What did you learn from doing this dissection? 3. How does the inside of a frog compare to the inside of a human? 4. What mistakes did you make while doing this dissection?