FROG DISSECTION
PROCEDURE:
•
GO to the website for the virtual dissection: http://www.mhhe.com/biosci/genbio/virtual_labs/BL_16/
BL_16.html
•
PLACE the frog in the dissecting pan belly side up.
•
FOLLOW along with the steps of the virtual lab to start your dissection.
•
USE tweezers to lift the THIN skin away from the body cavity.
•
CUT the same way to remove the THIN layer of muscles so that you can see the organs.
•
If there are fatty bodies (bright orange, yellow greasy noodles), use your scissors to CUT them away. Be
careful that you cut out the fatty bodies and NOT the intestines!
•
If you have a female frog you may see hundreds of eggs which look like black dots. REMOVE these eggs.
•
IDENTIFY each of the structures in the table below and check the box to show you’ve found them.
o ASK for help from your teacher if you cannot identify a structure.
•
FOLLOW the guidelines below to begin your dissection.
•
LAY OUT the structures on a paper on your table to show your teacher as you cut them away
STRUCTURE /
ORGAN
GALL
BLADDER
LIVER
HEART and
LUNGS
I HAVE
FOUND IT
WHAT DOES IT LOOK LIKE AND
WHERE IS IT?
HOW DO I REMOVE IT?
Under the liver there will be a
Use scissors to carefully
dark green small “grape” which
cut it out
stores the liquid bile
Use scissors to carefully
Brown colored large structure
cut it out. Do not damage
with three lobes (parts)
the organs underneath!
At the top of the liver there is a
small triangular structure which Use scissors to cut both
is the heart. Next to it are two the heart and lungs out.
little bags which are the lungs
I HAVE
REMOVED IT
FROG DISSECTION (continued)
STRUCTURE /
ORGAN
I HAVE
FOUND IT
WHAT DOES IT LOOK LIKE
AND WHERE IS IT?
HOW DO I REMOVE IT?
I HAVE
REMOVED IT
Remove the “food tube” from the frog
by cutting at the top and bottom of it.
You may also need to cut connective
tissue.
Stretch the tube out and MEASURE
the following lengths:
DIGESTIVE
SYSTEM
Under the liver you should
Length of frog = ______cm
now see the entire digestive
tube.
Length of tube =_____cm
Length of small intestines
=______cm
STOMACH
SMALL
INTESTINE
LARGE
INTESTINE
IDENTIFY the stomach, small
intestine, and large intestine
Cut lengthwise along the stomach to
This leads into the small
see if there is any food inside the
intestines.
stomach! Notice the stomach musclesthey looked ribbed.
Notice the very small blood vessels
The long thin tube that exits that are around the small intestine.
the stomach
This is where take the digested food is
taken into the blood stream.
The wider tube that leads
from the small intestine
Cut into the large intestine to see if
there is any waste (poop) there!!
Remove the KIDNEYS, which are two red organs located against the back of the frog’s abdomen.
- These can be removed by gently lifting them and cutting through the membrane that’s attached to the back.
On both sides of the spine and extending down to the legs, you will find NERVE BUNDLES that look like little
white threads.
- If you follow up the spine and look at the back on both sides of it, you will find more small bundles of nerves
branching out on both sides.