Lab Safety for Dissections
1.
Safety goggles must be worn at all times because the preservative is
very harmful to your eyes.
2.
If you are injured immediately notify the teacher.
3.
No horseplay or running around the room.
4.
Be careful because scissors are sharp.
5.
Absolutely no body parts leave the room. Dispose of them properly.
6.
Be sure to clean up and wash hands when you are done.
7.
No vomit in Stew’s room!!\
Earth Worm Dissection
1.
2.
3.
Insert the point of your scissors about 1 cm posterior to the clitellum
of the worm just to the left of center on the dorsal side. Be sure the
scissors are just under the skin. Carefully cut through the skin to the
mouth.
Using a dissecting needle, sever the muscles between the segments,
opening up the worm. Use pins to attach the skin to the dissecting tray.
Find the organs listed in your notes. Research their functions for your
dissection journal.
Materials
1. Tray
2. Two paper towels
3. Gloves
4. Scissors
5. Needles
Worm organs- find the function for the following organs.
Brain:
Aortic arches:
Crop:
Gizzard: Used to grind up organic food and it is the area of the digestive tube
which is quite muscular.
Intestine:
Dorsal blood vessel: The worm is darker on its upper surface.
Seminal vesicles:
Seminal receptacles: These are only visible when the worm is in reproductive
condition.
Esophagus:
Mouth:
Anus:
Clitellum: An organ that is responsible for mucus production during reproduction.
Skin:
Crayfish dissection procedure
1.
2.
3.
Observe the external anatomy of the crayfish. Locate the body
parts that are external. Is your crayfish a male or a female? How
do you know this? Locate the mouth of the crayfish. Observe the
live crayfish in the tank.
Make a cut in the exoskeleton of the cephalothorax on the dorsal
side from the back of the cephalothorax to the rostrum, cutting
down the midline. Separate the 2 halves of the exoskeleton to reveal
the internal organs.
After you find all the internal organs clean up thoroughly.
Materials
1. Tray
2. Two paper towels
3. Gloves
4. Scissors
5. Probe
Fish dissection procedure
1.
2.
Identify all the fins of the fish. Find the lateral line, operculum and gills.
Make a cut from the vent on the ventral side of the fish to an area just
below the operculum, cutting between the pelvic fins. Then cut up along
the operculum to the lateral line. Cut parallel to the lateral line until you
are even with the vent, then cut down to the vent and remove the side of
the fish. Locate the internal organs and then clean up thoroughly.
Fish organs
Operculum:
Gills:
Stomach:
Intestine:
Liver:
Heart:
Swim bladder:
Eye:
Ovaries:
Testes:
Caudal fin:
Dorsal fin:
Pectoral fin:
Ventral fin:
Pelvic fin:
Lateral line:
Scales:
Frog dissection questions:
1. How many chambers does a frog heart have?
2. How many chambers does a human heart have?
3. Which heart is more efficient, and why does it have to be more efficient?
4. Why does a frog have such small lungs?
5. How is the tongue of a frog attached in its mouth and why is it attached like
this.
6. Why is a frog classified as the following?
a. ectotherm
b. amphibian
c. chordate
d. animal
e. heterotroph
7. Why are amphibian populations declining, and what can we do to save them?
8. Explain how a frog is camouflaged.
9. Is a frog an herbivore, omnivore or carnivore? Explain your answer.
10. Why do scientists dissect organisms?
Frog organs
Skin
Lungs
Heart
Brain
Ovaries
Testes
Tongue
Cloaca
Spleen
Pancreas
Stomach
Small intestine
Large intestine
Liver
Gall bladder
Kidney
Bladder
Fat Bodies