RAT DISSECTION LAB
The rat is a vertebrate mammal, which means that many aspects of its structural organization are common with
all other vertebrate mammals. In a way, studying the rat is like studying most mammals.
As the leading theme of this lab, remind yourself: for every structure observed in the rat, there is an equivalent
structure in every mammal’s own body.
Important Dissecting Information: Dissecting tools will be used to open the body cavity of the rat and observe
the structures. Keep in mind that dissecting does not mean "to cut up"; in fact, it means "to expose to view".
Careful dissecting techniques will be needed to observe all the structures and their connections to other
structures. All cuts or injuries need to be reported immediately. Hint: Most incisions can use the scissors and
rarely need a scalpel.
Throughout the course of the investigation, you are to stop and have your teacher check your progress. At
each checkpoint, you should have the box initialed or stamped by your instructor to ensure adequate progress.
The checkpoints will include:
1. Rat skinned and muscles exposed in one area.
2. Remove muscles from one hind leg to expose the femur, tibia, and fibula.
3. Identify of structures in the thoracic and neck region.
4. Identify the organs in the abdominal cavity, including digestive system.
5. Removal and dissection of the kidney, the stomach and small intestines, and heart.
6. Identify the urogenital organs.
7. Turn in the rat and clean all tools/tray.
Answer the following questions on your binder paper. Get you teacher’s approval when required.
1. Draw a ventral and dorsal view of the rat and label all the external anatomy
2. Carefully remove the skin, to expose the muscles of the abdominal wall. Move slowly!
Completion Stamp:
3. Remove all tissue from one leg exposing the skeletal bones: femur, tibia, and fibula.
Completion Stamp
4. Make your incision into the abdominal and thoracic cavity. Expose and identify the organs in the thoracic
cavity to your teacher. Make a list of the thoracic organs identified and list their function. Completion
Stamp:
5. List and identify the organs in the abdominal cavity with your teacher. Next to each item, write the
organ’s function. Completion Stamp:
6. Remove the kidney, stomach, small intestines, and heart carefully. Once removed identify their
structures to your teacher. Completion Stamp:
7. Conclusion Question: To be completed after your dissection
a. Was your rat is male or female? How do you know?
b. The trachea of the rat has rings of cartilage on it, what are these rings for?
c. How is the structure and function of the male and female reproductive system beneficial for the
species to exist? Address both male and female systems in your answer.
d. Kidney failure is a life-threatening condition. Explain what this is and why it is life
threatening. Support your answer with specific examples.
e. The liver is an extremely important organ of the body with very complex function. Explain
and support this statement using specific examples.
f. Compare and contrast the rat and human muscular structures. How are they similar, yet
different?
g. What are 4 functions of the skeletal system? Explain each.
h. How do the fur on a rat and hair on a human serve similar purposes? How are they different in
function and location?
Structures you need to IDENTIFY to teacher or for Quiz:
External Anatomy
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Pinna (or aurical)
external nares (nostrils)
vibrissae
incisors
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thoracic region
eyelids
anus
hind and fore limbs
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papillae (nipples)
tail
external genitalia
abdominal region
Skeletal System
femur
tibia
fibula
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Abdominal Cavity Organs
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Liver
Stomach
Esophagus
Pancreas
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Spleen
Small Intestine
Gallbladder (not in the
rat)
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Large Intestine
- Colon
- Rectum
Urinary/Excretory System
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Kidneys
Ureters
Urethra
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Urinary Bladder
Adrenal Glands
Reproductive System
Male
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Testes
Scrotum
Penis
Seminal Vesicle
Vas Deferens
Epididymis
Female
• Ovary
• Oviducts (Also called
Fallopian Tubes)
• Uterus (Uterine horn in rat)
• Vagina
Thoracic Cavity Organs
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Lungs
Heart (Atria/Ventricle/Vena Cava)
• Trachea
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Diaphragm