Perch Dissection
Introduction:
Many of the fish's characteristics can give an insight as to how the human organism works. Dissection gives the student the opportunity to observe the placement of organs and their relationships to one another. In order to make this experience a valued learning one, it is important understand that observation will play a key role in this lab. Take your time and do not rush through the lab. Read all directions carefully; and make all your drawings as accurate as possible.
Materials:
- preserved perch
- dissecting tray
- dissecting kit
Procedure:
A. External Anatomy:
1. Place a preserved perch on a dissecting tray. Locate the head region.
2. Examine the eyes. Are there any eyelids present?
3. Examine the two flaps located on either side of the head. What is the name of these flaps, and what is their function?
4. Examine the 5 types of fins.
5. Locate the lateral line. What is the purpose of the lateral line?
6. Complete the questions on your lab sheet. Use complete sentences.
7. Draw and label the external anatomy of the perch. Label the following parts on your diagram: anal fin, caudal fin, eye, lateral line, mouth, operculum, pectoral fin, pelvic fin, soft dorsal fin and spiny dorsal fin. Remember- when completing your scientific drawing, use the guidelines given out in class.
B. Internal Anatomy:
1. 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.
2. Using your scissors, remove one of these layers. Examine the feathery structure.
3.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.
4. The fish contains a 2 chambered heart. Locate this organ found just behind and below the gills.
5. 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 oesophagus. This area is very elastic and can stretchwhen the fish is alive. How could this help the fish?
6. The oesophagus leads into the stomach. Locate the stomach.
7. Locate the rather large liver located just in front of the stomach.
8. Follow the intestine to the anus.
9. Locate the kidneys, found just below the spinal column. Their main function is to rid the body of nitrogenous waste.
10. The swim bladder is the last remaining organ to be identified. It is located between the kidneys and gonads. What is the function of the swim bladder?
11. Complete the questions on your lab sheet. Use complete sentences.
12. Draw and label the internal anatomy of the perch. Label the following parts on your diagram: gonads (sex organs), heart, intestine, kidney, liver, mouth, oesophagus, pharynx, stomach, swimbladder and vent. Remember- when completing your scientific drawing, use the guidelines given out in class.
Taken and modified from:
AOL Hometown, Mr. And Mrs. Smith’s Life Science Perch Dissection
Name: ______
Block: ______
Date: ______
Perch Dissection
External Anatomy:
1. Are there any eyelids present?
______
2. What is the name of the flaps that cover the gills?
______
3. How many fins? Caudal ____ Dorsal _____ Anal _____ Pelvic _____ Pectoral _____
4. What is the purpose or function of the fins? Explain at least 3.
______
5. Label the following parts on the diagram below: anal fin, caudal fin, eye, lateral line, mouth, operculum, pectoral fin, pelvic fin, soft dorsal fin and spiny dorsal fin
Internal anatomy:
1. The pharynx is very elastic and stretchy. How does this help the fish?
______
2. What is the main function of the kidney? ______
3. What is the function of the swimbladder? ______
4. Label the following parts: gonads (sex organs), heart, intestine, kidney, liver, mouth, oesophagus, pharynx, stomach, swimbladder and vent.
Conclusion: What was your overall impression of this dissection and what new things did you learn?
______
External View of Perch
Internal View of Perch
Internal View of the Perch
Taken from:
ZooLab