1. Frog Dissection
Grisham
Middle
School
Fall 2000
Jenna Hellack

2. PURPOSE: To study the external and internal anatomy of the frog to gain a better understanding of the human internal organs
CLASSIFICATION:
Kingdom - Animalia
Phylum - Chordate
Class Amphibia
Order Ranidae
Genus Rana
Species - pipiens
MATERIALS:
Preserved specimen, dissecting pan, scalpel, scissors, probe.
Fall 2000
Jenna Hellack

3. Frog Facts Frogs are part of the amphibian order, Anura.
Frogs have four legs, no neck, and no tails as adults.
Frogs have loose, mucous lined skin to help them escape from predators.
Frogs live "dual lives"--part in the water, part on land.
Frogs breath through gills only as tadpoles.
Frogs breath though underdeveloped lungs as adults.
Adult frogs also breath through their skin, called "cutaneous respiration," which limits body size.

4. Frog Facts
The backs of frogs are dark, while their undersides are light, in order to protect them through camouflage on land and water, respectively.
Frogs live on land as adults, but must live near a major water source to help keep their skin moist, for reproduction, and for certain stages of life.
Strong muscles and special fused bones help frogs be powerful swimmers and jumpers

5. Ethics of Dissection The frogs are not here for your amusement
They are here to help you learn about your own internal organs
You will not handle the frog inappropriately
You will not act as if the frog is animated
You will not make any inappropriate sounds while dissecting the frog
If you chose to act in a disrespectful manner, you will be removed from the lab without any further warning

6. What your frog will look like
It is a green grass frog.
Fall 2000
Jenna Hellack

8. Day 1: External Examination

9. Frog Dorsal view
Muscle index

10. Frog ventral anterior muscles
Muscle index
Frog ventral anterior muscles
Muscles contrasted
7. Deltoid
Pectoralis
Rectus abdominis
Linea alba
External oblique

11. Day 2: Examining the Mouth
Lay the preserved frog on its back. Cut the jaws apart at the hinges in order to open its mouth wide.
Find the following structures:
Maxillary teeth
Vomerine teeth
Eustachian tubes
Tongue
Glottis
Esophagus
Tympanic membrane

12. Frog mouth 30. Maxillary teeth 31. Vomerine teeth 33. Eustachian tubes
34. Tongue
35. Glottis
36. Esophagus

13. Day 2: Examining the Internal Organs
Cut through the muscles of the abdomen the same way you made the skin incisions
Find the Liver and remove it.
At this point you may also see fat bodies and if you have a female, masses of eggs.

14. Day 2: Examining the Internal Organs
Find and remove the following : stomach, intestine, pancreas (behind stomach), gall bladder (clear/green)
Find and remove the following : heart, right and left lungs
Find and remove the following: spleen (reddish), kidneys (dark brown)

15. Frog Internals Ventricle Auricle (atrium) Conus arteriosus
Aortic arches
Liver
Fat bodies
Urinary bladder

16. Frog Internals Auricle (atrium) Ventricle Conus arteriosus Lung Liver40 38 44 46 51 49 47 52 55 39 42 43 50
Auricle (atrium)
Ventricle
Conus arteriosus
Lung
Liver
Gall bladder
Small intestine
Large intestine
Spleen
Kidney
Fat bodies
Urinary bladder
Adrenal gland