Perch Dissection                        Name _____________________ Period____
SmithLifeScience

Introduction:

Many of the fish's characteristics can give an insight as to how the human body works. Dissection gives you the opportunity to observe the placement of organs in a perch.  Make this experience a valued learning one, take your time and do not rush through the lab. Read all directions carefully; and make all your drawings as accurate as possible.

Procedure:

A. External Anatomy:

1. Place a preserved perch on a dissecting tray.  Locate the head region.  Examine the eyes. 

2. Are there any eyelids present? _______. 

3. Draw the eye in the space below.


  
 

4. Label the eye on the external view of the fish.

5. Examine the two flaps located on either side of the head. 

6. What is the name of these flaps? ________________________

7. What is their function? __________________________

8. Label the flaps on the external view of the fish.

                                            

9. Examine the 5 types of fins. In each box below, draw one of the fish's five types of fins. 

10. Label each fin on the external view of the fish.

11.. How many fins?  Caudal ____ Dorsal ____ Anal ____ Pelvic ____ Pectoral ____

12. Each fin has a purpose or job, what is the purpose of the following fins?

          a). caudal fin_________________                d). anal _________________

          b). dorsal fins________________                 e). pelvic ________________

          c). pectoral fin _______________

13. Locate the lateral line. Using the hand lens and look at the line and the surrounding area.
14. Draw the lateral line in the space below.



15. Label the lateral line on the external view of the fish..

                           


B. Internal Anatomy: Gill

16. Using your thumb, lift up the edge of the operculum and raise it up as far as you can. Using your
scissors, cut the operculum off as close to the eye as possible. You have exposed the gills. The gills are layered one on top of another. Using your probe, carefully lift each of these layers.

17. How many layers do you find? ___________

18. Using your scissors, remove one of these layers. Examine the feathery structure.

19. Draw the gill structure in the space below.

20. To expose the internal organs you will cut away part of its muscular wall. Grasp your fish, holding it with your thumb on one side and fingers on the other. Turn your hand upward to expose the ventral surface. Using your scissors, insert the point into the skin just in front of the anus. Cut forward to the gills. Be careful not to destroy any of the internal organs, since they are mostly found in this area. Place your thumb into the open cut area and lift up, separating the bottom from the top. Using your scissors, cut upward near the anus and the operculum and form a flap of skin and muscle. Finish cutting along the lateral line and remove the flap of tissue. See the figure below.

Figure 2.

                                     
 21. The fish contains a 2 chambered heart. Locate this organ found just behind and below the gills.
       Label the parts of the heart below. 

                                                            Fish Heart

22. Part 1 _______________ Function: _________________

23. Part 2 _______________ Function: _________________

24. Label the heart on figure 3.

25. Locate the tube-like digestive system. Begin just behind the mouth in the area called the pharynx. This area leads into the gullet or the opening of the esophagus. This area is very elastic and can stretch when the fish is alive. 
26 How could this help the fish? _____________________________________

27. Label the mouth on figure 3.

28. Label the pharnyx on figure 3.

29. Label the esophagus on figure 3.

30. The esophagus leads into the stomach. Cut out the stomach and split it open.

31. Draw the inside of the stomach in the space below. 





32. Label the stomach on figure 3.

33. Locate the rather large liver located just in front of the stomach.

34. Draw the liver in the space below.






35. Label the liver on figure 3.

36. Follow the intestine to the anus.

37. Label the intestine and anus on figure 3.

38. Locate the kidneys, found just below the spinal column. Their main function is to rid the body of nitrogenous waste.

39. Label the kidneys on figure 3.

40. The swim bladder is the last remaining organ to be identified. It is located between the kidneys and gonads.

41. What is the function of the swim bladder_____________________________________

42. Label the swim bladder on figure 3.

Figure 3 Internal View of Perch