1. Why Dissect. Why are frogs a good model to use when studying the digestive system (as well as other systems)?

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1 Name: Date: Period: Frog Dissection Virtual Lab Use the frog Dissection link that follows to answer the questions. Introduction 1. Why Dissect. Why are frogs a good model to use when studying the digestive system (as well as other systems)? 2. What does the word amphibian mean? Why are frogs classified as amphibians? 3. What is in the dissecting pan for you to use to pin the dissected animal down? 4. What other tools will you use to dissect? Click on Menu on the bottom at the bottom of the page when you are ready to move on to the next section External Anatomy 5. Orientation. Is it possible to tell if a frog is male or female by external appearance? 6. Skin. What does the mucus do for the skin? 7. Head. Where are the tympanic membranes (eardrums)? Do frogs have a pinna? 8. Cloaca. What materials would pass through a cloaca. 9. Legs. How many hind leg toes does a frog have? Click on Menu on the bottom at the bottom of the page when you are ready to move on to the next section Internal Anatomy 10. The Initial Cut. Are you suppose to push the pins in at an angle or straight down? What is the benefit of pushing the pins in this way? 11. The Initial Cut. Describe the first cut you will be making. Include where you will be cutting and how deep. 12. The Initial Cut. Why are there so many blood vessels in between the skin and muscle layers?

2 13. Digestive System. Which organ is the pancreas located closest to? 14. Digestive System. The movie asks you to remove the intestines. What other organ(s) is/are removed with the intestines when you click on the tweezers? 15. Respiratory System. What does the skin do in frogs that it does not do in humans? 16. Respiratory System. Where are the lungs located in a frog (relative to the heart)? 17. Circulatory (Cardiovascular) System. How many chambers does a frogs heart have? 18. Circulatory (Cardiovascular) System What is a frogs heart missing when compared to a humans (what chamber)? 19. Circulatory (Cardiovascular) System Why is the three chambered heart not as efficient as a four chambered heart? 20. Reproductive System. In your own words, describe where are the testes located? 21.Reproductive System In your own words, describe where are the ovaries located? 22. Excretory System. What happens to blood that enters the kidneys? 23. Excretory System What organ connects the kidneys to the (urinary) bladder? 24. Nervous System. This video is long, and parts without sound. Please watch patiently. What makes up a frogs nervous system? 25. Muscular System. Which part of the body are frog s muscles in the upper leg responsible for moving? 26. Skeletal System. How many bones are found in the axial region? 27. Skeletal System. How many bones are found in the appendicular? 28. What was the purpose of this lab? Use this link to answer these questions What is the major organ visible upon opening the abdomen of the frog? What side (dorsal or ventral) is it? 30. What is the j-shaped organ under the liver? 31. Is the head end of the frog anterior or posterior?

3 32. Is the tail end of the frog anterior or posterior? 33. What are the yellow, finger-like structures seen? 34. What is the clear sac near the bottom of the frog that connects to the kidney? 35. How many chambers are in the frog s heart? 36. In what organ are the ruggae found? Use the link that follows to answer the next questions How do frogs keep from freezing when they hibernate? 38. Name 2 reasons frogs secret mucus and feel slimy. A. B. 39. What unusual thing can frogs do with their eyes? How does this benefit them? 40. How does a frog get most of its oxygen even though it has lungs? 41. Where is a frog s tympanum? What is its function? Use the link that follows to answer the next questions The membrane that holds the coils of the small intestine together: 43. This organ is found under the liver, it stores bile: 44. Name the 3 lobes of the liver:,, 45. The organ that is the first major site of chemical digestion: 46. Eggs, sperm, urine and wastes all empty into this structure: 47. The small intestine leads to the: 48. The esophagus leads to the: 49. Yellowish structures that serve as an energy reserve:

4 50. The first part of the small intestine(straight part): 51. After food passes through the stomach it enters the: 52. A spider web like membrane that covers the organs: 53. Regulates the exit of partially digested food from the stomach: 54. The large intestine leads to the 55. Organ found within the mesentery that stores blood: 56. The largest organ in the body cavity: 57. A frog does not chew its food. What do the positions of its teeth suggest about how the frog uses them? 58. Using words, trace the path of food through the digestive tract. 59. Using words, trace the path of blood through the circulatory system, starting at the right atrium. 60. What do you think is the function of the nictitating membrane, and why? 61. Which parts of the frog s nervous system can be observed in its abdominal cavity and hind leg? 62. Suppose in a living frog the spinal nerve extending to the leg muscle were cut. What ability would the frog lose? Why? 63. The abdominal cavity of a frog at the end of hibernation season would contain very small fat bodies or none at all. What is the function of the fat bodies? 64. Structures of an animal s body that fit it for its environment are adaptations. How do the frog s powerful hind legs help it to fit into a life both in water and on land?

5 Label Diagram A. Internal Organs B. C. D. E. F. G. H. I. J. K. L. M. N.