Rat Dissection
Purpose:
Orientation to dissection; learn to use dissecting tools correctly; learn to treat dissection specimens carefully and
appropriately; explore the anatomy of the rat; identify and remove whole organs and organ systems
Materials:
 Dissecting Kit (1)
 Dissecting Tray (1)
 T-Pins (10)
 Labeled T-Pins (1 set)
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Organ Card with Plastic
sheet (1)
Paper Towels
Waste Beaker (1)
Wash Bottle (1)
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Dropper Pipette (1)
Goggles, Gloves, and
Aprons for those
handling specimen
NOTE: ANY STEPS IN BOLD REQUIRE YOU TO WRITE AN ANSWER ON YOUR OWN PAPER!
Procedure:
SECTION 1
1) On the Rat Dissection Gradesheet, write your members names, leader, the period, and lab station
2) Make general observations about the exterior surface of your rat (color, size, eyes, teeth, etc.)
SECTION 2
3) Pin rat flat to Dissecting Tray
a. Lay the rat in the dissecting tray so that its anterior surface is facing up.
b. Pin the rat flat to the dissecting tray
 Place T-pins through each arm and leg to hold the rat down on the tray
 This will require some force, and you may hear cracking and snapping. This is OK.
SECTION 3
4) Determine the sex of your rat (male or female)
a. Look for the genital area inferior to the abdominal cavity, medial to the back legs, ventral to the
tail.
 Males have a large pair of scrotal sacs, which contain testes. Anterior to the scrotal sacs is a
bulge of skin around the penis.
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Females have two small openings in the genital area, one urogential orifice (where urine
exits), and one vaginal orifice.
CHECKPOINT 1
STOP! Say “Checkpoint” when you are ready for Mr. D to grade you!
SECTION 4
5) Open the Abdomen (using ONLY forceps and scissors)
a. Follow the incision guide
 Use the forceps to pull up some loose skin on the lower abdomen and snip an opening in
the skin with the scissors
 FIRST, make an incision from the belly button up to the top of the neck
 SECOND, make two incisions from the center of the thoracic region to just under the right
and left arms.
 THIRD, make two incisions from the top of your first incision over to the right and left
sides of the neck
 LAST, make two more incisions from the bottom of your first incision to the right and left
hips.
 Pin back the skin flaps with T-pins
 You will notice a brownish fluid inside the rat.
1. Use a dropper pipette to remove the fluid from the body cavity of the rat.
2. Use the wash bottle to rinse the abdomen with water
3. Remove all excess liquid from the abdomen with the dropper pipette
Incision Guide 1
Incision Guide 2
First Incision up the center of the body
Second Incisions from center cut to under arms
Third incisions from top of center cut to sides of
neck
Fourth Incisions from bottom of center cut to hips
Pinned back skin
CHECKPOINT 2
STOP! Say “Checkpoint” when you are ready for Mr. D to grade you!
SECTION 5
6) Use the diagrams below to Find and Flag with T-Pins:
Trachea
Lungs
Heart
Liver
Stomach
Kidneys
Intestines
CHECKPOINT 3
STOP! Say “Checkpoint” when you are ready for Mr. D to grade you!
SECTION 6
7) Remove (using scalpel VERY GENTLY, and probes), rinse thoroughly, and place on laminated Organ Card:
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Heart
Lungs with Trachea/Esophagus
Liver
Stomach with Intestines
Kidneys with Ureters/Urethra
LIVER
HEART
LUNGS WITH
TRACHEA/ESOPHAGUS
STOMACH AND INTESTINES
KIDNEYS WITH
URETERS/URETHRA
CHECKPOINT 4
STOP! Say “Checkpoint” when you are ready for Mr. D to grade you!
STOP! Make sure Mr. D takes your final organ picture.
CLEAN UP PROCEDURE
After Mr. D has photographed your Dissection Organ Palate, you may begin the clean-up procedure
1) Keep all safety equipment (goggles, gloves, apron) on until you are done with clean-up
2) Dispose of all of the following items the designated waste basket
a. Rat and rat organs
b. Dropper pipette
3) Dispose of all liquid waste from the lab in the designated bucket
4) Wipe all remaining items (dissecting tools, dissecting tray and mat, beakers, etc) with paper towels until
they look clean
5) All items that were just wiped will be washed in the wash basins as follows
a. Wash in warm soapy water
b. Rinse
c. Dip in bleach water
6) Lay all items to dry as instructed
7) Clean your table with 409 or Clorox Wipe
a. NOTHING should be in the sink!
8) Check lab drawers for anything “accidently” misplaced including paper, gum, wrappers…
9) Call me over for inspection. Once I have approved your clean-up, you may remove your safety
equipment and wash your hands.