Frog Dissection
Rules
1. Do not use any of the sinks!
 2. Do not leave your seats once
dissection begins.
 3. Do not run, play or roughhouse!
 4. Be extremely careful with the tools.
 5. Do not ask to go to the bathroom.
 6. Do not skip ahead. This is not a
race!

Rules
 7.
Be sure all tools are in the
case! Do not throw them away.
 8. We do not leave until
everything is clean!
 9. Do not keep any body parts.
Throw everything away!
Rules
 10.
Do not make any cuts until I
tell you to do so!
 11. If you are squeamish with the
animals, don’t partner with
someone that is squeamish!
 Failure to follow these rules will
result in a ZERO for today’s lab!
External Anatomy
Frog
 The
purpose of this
dissection is to learn about
the anatomy of the frog and
how different parts of the
anatomy function.
External Anatomy
 Examine
the external
anatomy of the frog locating
the following parts:
Tympanum, eyes, webbed
feet, skin, tongue and teeth.
Head Region
Membrane –
eardrum around
membrane just behind
the eyes.
Tympanic
Mouth
 Observe
the tongue
 Maxillary Teeth– Found on the
upper jaw
 Vomerine Teeth– Found in the
front of the mouth near the
center.
Internal Anatomy
Let’s Begin
 1.
Turn the frog over on its
back with the head away from
you.
 2. Cut off both arms using
your scissors.
 3. Using your forceps, lift the
skin of the belly and make a
slit with your scissors.
 4. Now cut upwards towards
the mouth of the frog.
4.
Look at the following
picture and make the
same cuts.
5. Cut off the resulting
flaps of skin.
 6.
Notice the smooth muscle
beneath the skin.
 7. Now repeat the procedure,
this time cutting through the
muscle. Be careful not to cut
into the internal organs.
 8.
You may notice a
yellowish tissue with
long finger like lobes.
This is called fat bodies.
Remove them with your
forceps. (Our frog did
not have fat bodies)
Digestion
We
will now find the
following: mouth, liver,
stomach, intestines,
cloaca, pancreas.
 9.
Notice the liver,
which is a brownish
organ with three lobes.
10. Lift the liver and
observe the greenish
sac beneath. This is
called the gall bladder.
 11. Using your scissors
cut and remove the liver.
12.
Observe the
stomach. Notice it is
attached to the
intestines. Uncoil the
intestines. See picture
on next slide.
Cut here
 13.
Completely remove
the stomach using the
scissors.
 14. Now you will cut
open the stomach to
observe what the frog
ate. See picture on next
slide.
Circulatory System
 15.
Make a cut with your
scissors through the frog’s
chest. Using your hands,
break open the chest to
expose the heart.
 16. Remove the heart
using your scissors.
Respiration
19.
Observe the lungs.
They lie right below the
heart. Cut and remove
the lungs.
Excretion
Kidneys – Two
flattened organs lying on
the back side of the body
cavity.
 21. Cut and remove them.
 20.
Muscles and Skeleton
22.
Notice the backbone
of the frog.
23.
Remove the skin
from the upper part of
the hind leg. Note the
muscles.
Lab Questions
1. What is a Tympanic Membrane?
 2. Where are the Maxillary teeth
located?
 3. Where are the Vomerine teeth
located?
 4. What are the yellowish tissue with
long fingerlike lobes?
 5. What is the brownish organ with 3
lobes?

Lab Questions (Continued)
6. Where are the lungs located?
 7. Where are the kidneys located?
 8. Where is the gallbladder located?
 9. What are the organs of the frog’s
digestive system?
 10. What long organ is attached just
below the stomach?

Conclusion Questions- Answer in
complete sentences, in paragraph form



1. What did you learn from doing this
dissection?
3. How does the inside of a frog compare
to the inside of a human?
4. What mistakes did you make while
doing this dissection?