You will use this packet as your procedure packet as well as a study guide.
I will be checking review questions the next day so that you can finish any for HW.
Name: _____________________________________________
General Instructions
These procedures will be followed on a daily basis. Please keep referring to this page of your packet to
make sure that you are following ALL directions!
Safety:
1. All members of your group MUST be wearing safety glasses/goggles.
2. Gloves are available and optional.
3. Absolutely NO FOOD, including gum.
Instruments:
1. Each group is responsible for one dissection try.
2. Your dissection tray will include the following tools:
a. Two pairs of scissors
b. Two probes
c. Two pairs of forceps
d. Eight (8) pins
Storage:
The frog will be studied for more than one class period. It is important to keep them
moist and easily identifiable.
1. Make sure that the toe tag is securely attached to your frog and ALL GROUP
MEMBERS’ NAMES are on the tag and easy to read. Please ask if you need a new
tag.
2. Wrap your frog in a damp paper towel to prevent it from drying out.
3. Place your frog in your class period’s ziplock bag.
Cleanup:
1. Wrap any removed parts in a paper towel and discard them in a waste container.
DO THIS BEFORE WASHING OUT YOUR TRAY!
2. Rinse and dry all dissection instruments, including your tray and return them to
the proper storage location.
3. Spray down lab tables with antiseptic.
4. Everyone is responsible for cleaning up after themselves and NO ONE leaves the
classroom until EVERYTHING is cleaned up!
Day One: External Structures of the Frog
Label the appropriate parts of the frog’s external structures.
Directions:
1. Place frog on the dissection try belly side down. Do not pin the frog at this time.
2. On the outside of the frog, locate and observe the following structures-turn the frog as
needed to refer to the diagrams.
3. All organisms have sides to their bodies. Each side is given a specific “Scientific” Name.
The head end is known as the anterior end, the rear end is known as the posterior end,
the backside is known as the dorsal side, and the belly side is known as the ventral side.
4. Label the above diagram of the frog as appropriate.
5. Observe the frog’s exterior (outside). The frog has a head and trunk. The head contains
the brain, mouth, eyes, ears, and nose. The trunk contains all of the frog’s internal
organs.
Procedure:
1. Observe the following structures. You are responsible for know the structure, function, and
location of all of the bold words. Complete the questions. Follow the bolded and underlined
directions.
a. Look at the head found at the anterior end.
o
o
Find the mouth- a large opening at the front of the head of the frog. It
has both upper and lower jaws.
Look at the nostrils- the two small holes just above the mouth.
o
Find the eyes- The frog has three (3) eyelids. To close its eye, the frog
must pull its eyeball into its socket
o
Look at the eardrum known as the tympanum- the eardrum is a round
membrane found on each side of the head.


What is the frog’s ear missing? __________________________
What does it look like to you? __________________________
b. Look at the frog’s trunk- The portion of the frog’s body located behind its head.
c. Look at the appendages also known as the arms and legs.
o
Find the forelimbs or front legs
o
Find the forelimb digits or fingers

o
o
How many fingers does your frog have? _____________
Find the hind limbs or back legs
Find the hind limb digits or toes.

o
What type of joint does its leg have?
___________________________
How many toes does your frog have? ____________
Look at the skin- Frogs have very special skin! The skin of a frog IS NOT
used for protection- Frogs drink and breathe through their skin.
o
Look inside the mouth- Pry open the mouth with the probe and observe
the mouth and throat. To loosen the jaw, you will need to cut the jaw
(mandible) joint with the scissors.


o
o
o
Find the internal nostrils- These are holes found at the roof of the
mouth. Use the probe to see how the internal and the external nostrils
are connected.
Find the throat- it’s the area at the back of the mouth. You MAY have to
tilt your frog’s head back to be able to see the throat better.
Behind the throat is the esophagus.

o
Find the maxillary teeth- They
are found along the top jaw. Run
your finger along the jaw line to
feel that the tiny teeth feel like
sand paper.
Find the volmerine teeth- These
are the two larger teeth found
near the front of the roof of the
mouth. They should be in the
center.
What does the esophagus do?
____________________________________________________
Look at the frog’s tongue- Notice that it is attached near the front of the
mouth.

Why do you think the tongue is attached to the front of the
mouth?
____________________________________________________
____________________________________________________
Day One: Review Questions
Answer the following review questions from Day One’s Dissection for homework. These questions will be
checked and graded upon completing the dissection project. You will also be responsible for knowing the
material covered in these questions for your Practical Exam.
1. List the proper names for the following sides of the frog:
a. Back Side- _______________________________
b. Belly Side- _______________________________
c. Rear End- ________________________________
d. Front End- _______________________________
2. _____________________________________________________________ are the two small
holes outside the mouth.
3. The __________________________________ are two small holes in the roof of the mouth.
4. The frog has ________________ eyelids (number of eyelids).
5. The proper name of the eardrum is the __________________________________________.
6. The frog’s ear is not like a human’s. It is lacking an __________________________________.
7. The three functions of the frog’s skin are to ________________________________,
______________________________ and __________________________________.
8. The _______________________________ teeth are located along the top ridge of the jaw.
9. The _______________________________ teeth are located at the center of the
roof of the mouth.
10. The _________________________ takes food to the stomach.
11. The tongue is attached to the ______________________ of the frog’s mouth.
Day Two: Internal Structures of the Frog
Procedure:
1. Turn the frog on its dorsal side with the ventral side up. If you are
unsure of which side is which, refer back to Day One. Hold the frog in
place by pinning each hand and foot to the dissection tray. ONLY
USE ONE PIN PER LIMB AND WAIT!
2. Follow the directions given by your teacher to cut the skin on the
ventral side of the frog.
3. Pin the flaps of skin you just cut to the dissection tray. DO NOT CUT
THEM OFF!!
a. Look at the abdominal muscles- the layer of muscles that
make up the wall of the abdomen. NOW WAIT!
4. Follow the directions given by your teacher to cut the muscles. You
will cut the muscles in the same fashion you did for the skin. Be
careful and do not cut any organs! Be prepared to cut through
bone!
5. Pin the flaps of muscle to your dissection tray the same way you pinned the skin down. Observe
the organs that are in view.
Body Systems
1. Circulatory System
o Find the heart located in the center of the chest.
o Frogs have a ______________-chambered heart. They have
a right and left atrium (plural: atria) and a single ventricle.
o Find the liver- brownish organ that is divided into
___________________ parts. It is the largest of the internal
organs.
 What is the function of the liver?
__________________________________________
__________________________________________
__________________________________________
o
Find the spleen- a reddish-brown oval structure (looks like a
small pebble). Its function is to destroy bacteria, old red
blood cells, and platelets. It also stores and releases blood in times of demand.
2. Respiratory System
o Find the lungs-they lie under and to the right and left of the
heart.
 What is the function of the lungs?
_____________________________________
--- CALL YOUR TEACHER AND WAIT! –
a. Remove ONE lung.
b. Cut the lung open along its length to observe the small
chambers and sack-like structure of the lung.
c. Observe the lung under the stereoscope.
3. Digestive System
o Find the esophagus- Use your probe to see how the esophagus leads to the stomach.
o Find the stomach- this is a long white organ on the left side of the body cavity.
 What does the stomach do?
_______________________________________
 Why do you think the stomach is so large?
______________________________
_______________________________________
--- CALL YOUR TEACHER AND WAIT! --o
o
Cut open the stomach lengthwise to observe the foods
eaten by the frog.
Observe the folds of the stomach lining.
 Did your frog have anything in its stomach?
__________________
 If yes, what did you find? ____________________________________________
_________________________________________________________________
(Digestive System Continued…)
o
Find the small intestine- small coiled tube attached to the bottom of the stomach. Be
very careful when observing this organ! The pancreas is a very thin organ attached to
the side of the small intestine and tears easily!
 What is the function of the small intestine?
_________________________________________________________________
o
Find the large intestine- large tube that is attached to the end of the small intestine.
 What is the function of the large intestine?
_________________________________________________________________
o
Find the gallbladder- small round, dark (often greenish) sack attached to the back
surface of the liver.
 What is the function of the gall bladder?
_________________________________________________________________
o
Find the pancreas- ASK YOUR TEACHER FOR HELP- This is a flattened organ found in the
tissue between the small intestine and the stomach.
 What is the function of the pancreas?
_________________________________________________________________
Day Two: Review Questions
Answer the following review questions from Day One’s Dissection for homework. These questions will be
checked and graded upon completing the dissection project. You will also be responsible for knowing the
material covered in these questions for your Practical Exam.
1. The layer of muscles that make up the abdomen are called the
___________________________________________________.
2. The function of the heart is to __________________________________________________.
3. The frog’s heart has _____________________________ chambers.
4. The chambers of the frog’s heart are the __________________________,
___________________________, and _________________________________________.
5. The liver is divided into ______________________________ parts.
6. The function of the spleen is to _______________________________________________.
7. The function of the lung is to_________________________________________________.
8. The lungs re so small because
________________________________________________________________________.
9. The function of the stomach is to _____________________________________________.
10. The stomach is so large because the frog _______________________________________.
11. The small intestine is coiled / straight (circle one)
12. The function of the large intestine is to _________________________________________.
13. The function of the liver is to _________________________________________________.
14. The function of the gallbladder is to
____________________________________________.
15. The function of the pancreas is
to______________________________________________.
Day Three: Internal Structures of the Frog
Continued
Procedure:
1. Excretory System
o Find the kidneys- two reddish-brown, flattened organs lying on the back surface of
the body cavity. You will need to remove the membrane covering them to get a
good look. Kidneys are responsible for removing wastes and excess water from the
body.
2. Reproductive System
 Is your frog male or female? _________________________________
o If you have a female frog, find the ovaries- black and white in color. Ovaries produce
reproductive cells called eggs.
(The Female Frog)
o If you have a male frog, find the testes- each testis is a small oval organ attached to
the front surface of the kidney. Typically they will be found with in the fat bodies
near the kidneys. The testes produce
reproductive cells called sperm.
(The Male Frog)
If you have a female frog, you will NEED to look at a male
frog. If you have a male frog, you will NEED to look at a
female frog.
o
Find the fat bodies- fat bodies are long, finger-like yellowish tissue. They are
responsible for storing fat.
2. Skeletal System
o Frogs have a single lower arm
bone called the radioulnathe radius and ulna are fused
together!
i. Cut through the skin
and muscle of the
left forelimb to
expose the
radioulna. CALL
YOUR TEACHER FOR
HELP!
o
Frogs have a single lower leg
bone called the tibiofibulathe tibia and the fibula are
fused together!
i. Cut through the skin
and muscle of the
left hindlimb to expose the tibiofibula. CALL YOUR TEACHER FOR HELP!
 How are the frog’s lower arm and leg bones different from ours?
____________________________________________________________________
Day Three: Review Questions
1. The function of the kidneys is to ____________________________________________.
2. The ovaries are ____________________________________ in color.
3. The testes are typically found near the ___________________________________.
4. The function of fat bodies is to ________________________________________.
5. The proper name for the lower arm bone is the ________________________.
6. The proper name for the upper arm bone is the _______________________.
7. The frog’s lower arm and leg bones are different from ours because they one have
________________________ bone instead of two.
8. We dissected a __________________________________ frog. (Species of frog dissected).