Dissecting the Frog Follow and fill in your notes as we read together. You may have your notes on you at the time of dissection

Review – Terms of Orientation L Review – Terms of Orientation D M Anterior Front end Posterior Back end Dorsal Upper surface or back Ventral Under surface Medial Lies close to the mid-line of the body Lateral Away from the mid-line A P V

External Anatomy Skin Dorsal – green/brown Ventral – off white Purpose? Ventral – off white Thin and flexible Water can pass through it Veins in skin Can get O2 in the winter Have mucus glands Some produce toxins to ward off predators Keeps skin moist                                                                                                                         

External Anatomy Head External nostrils Eyes Tympanums Upper and lower eyelids Nictitating membrane Purpose? Tympanums Function?

External Anatomy Trunk 2 front limbs 2 hind limbs Upper arm Fore arm Wrist Hand – four digits 2 hind limbs Thigh Shank Ankle Foot – five digits Webbed Function?

External Anatomy Cloacal Opening Waste products exit Urine from the kidneys Fecal matter from the intestines Reproductive products exit Egg sperm

External Anatomy Mouth Top of mouth Rear of mouth Internal nostrils Vomerine teeth Maxillary teeth Rear of mouth Esophagus (gullet opening) leads to stomach Glottis Leads to trachea and lungs

External Anatomy Mouth Tongue Eustachian tubes Vocal sacs Large, fleshy Attached at front of mouth Eustachian tubes Attach to the eardrums (tympanums) Equalize air pressure (same function in humans) Vocal sacs Only in males Used for mating calls

In Order to Observe the Mouth, you have to cut the jaws with a scissor.

Internal Anatomy Place frog on dorsal side Pin it at the wrist and ankles (angle pins away from frog) Make incisions through the skin as shown in the diagram

Skin first, then cut away muscle that’s underneath

Internal Anatomy Major organs to dissect Heart Liver Stomach Small intestine Large intestine Gall bladder Lungs Kidneys Spleen

Tough organs to find – kidney and spleen (fat bodies can be taken out and thrown away)

Dissecting tools Dissecting Pan Scalpel Forceps Dissecting Needle Dissecting Probe Scissors Metric Ruler Dropper Dissecting Pins