Download FROG DISSECTION

FROG DISSECTION
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Groups of 2 or 3 – Choose your partners carefully as each person in the group will
be accountable.
Follow directions diligently and exercise safety precautions and common sense.
If you are unsure about anything, stop, reflect and if need be, ask the teacher.
Part 1: External Structures
Rinse your specimen in water and place it on the dissection tray
A. Make a scientific drawing of the frog:
a. A dorsal view
b. A ventral view
c. A side view
B. Identify in each of your sketches were applicable the following structures:
a. Eyes
b. External nares
c. Tympanum
d. Nictitating membrane
e. Forelimbs
f. Hindlimbs
g. Anus (cloaca)
h. Skin
i. Teeth
Questions:
1.
2.
3.
4.
5.
What is the purpose of the nares?
What is the purpose of the tympanum?
What is the major difference between the ventral side and dorsal side?
What are some differences between the types of limbs?
What is the purpose of the teeth?
C. Examine the skin.
Describe some of the features of the skin.
D. Open your frog’s mouth.
You may need to make small cuts at the hinges to open it wider.
Make a simple drawing of what you see.
Can you identify any parts?
Part 2: Internal Structures
A. Write your procedure to make the cuts to open the frog. (teacher must approve your
procedure before continuing)
B. Make the cuts.
a. Examine the inside of the frog noting the structures that are visible.
Use the images on the SmartBoard to help you identify those structures.
Question:
6. What structures do you see and what systems are they a part of?
Group the structures into the different systems.
b. Carefully lift the liver.
Question:
7. Describe what you see below the liver. What structures do you see and what
systems are they a part of?
Group the structures into the different systems.
C. Removing organs.
a. Using a probe and scissors, lift and remove the liver.
Place the liver to the side.
b. Remove any fat bodies and place them to the side.
c. Remove the stomach and place it aside.
Make a scientific drawing of the external structures of the stomach.
d. Carefully open the stomach lengthwise and open it up.
Question:
8. Describe what you see in the stomach.
9. After removing fat bodies, the liver and the stomach, are there new structures
visible? Identify any new organs now visible and state what system they belong
to.
e. Remove the heart (keeping arteries attached) and place it aside.
Make a scientific drawing of the heart and label the parts.
f. Carefully dissect the heart.
Make a scientific drawing of the interior of the heart and label the parts.
g. Remove the lungs and place it aside.
Get an eye dropper (pipette) and try to inflate the lung.
Question:
10. Describe what happens to the lungs.
h. Examine the small and large intestine.
Question:
11. Describe the location, shape and structure of the small and large intestine.
i. Locate the reproductive organs of your frog.
Describe the types of organs that are present and confirm the sex of your
frog.
D. Carefully remove other organs and place them aside and identify them.
Using the organs that you put aside, reconnect next to your frog the organs back into
organ systems.
Make a scientific drawing of your different organ systems, labelling the parts.
E. Clean up and return all components to where you got them.
Dispose of frog as directed by your teacher.