Frog Dissection!

Frog Background Animal Class: Amphibian Where frogs live: Many live on land, but they must return to water to reproduce because eggs are laid and fertilized in water. Body: Head- are two nostrils; two eardrums; and two eyes that have three eyelids! The third eyelid, called the nictitating membrane, and it is transparent. Mouth- two openings into the nostrils; two vomerine teeth in the middle of the roof of the mouth; and two maxillary teeth at the sides of the mouth.

Before you cut Look at the eyes, ears, forearms, Inside mouth

Skeletal and Muscular The frog’s skeletal and muscular systems consist of its framework of bones and joints, to which nearly all the voluntary muscles of the body are attached. Voluntary muscles, which are those over which the frog has control, occur in pairs of flexors and extensors. When a flexor of a leg or other body part contracts, that part is bent. When the extensor of that body part contracts, the part straightens.

No ribs!

Respiratory System….just like us! The frog respiratory system consists of… -nostrils to let air in - larynx that connects to two lungs with alveoli -lining of the lungs are also filled with capillaries just like us!

Circulatory System…not quite like us 3 chamber heart with two atria, and one ventricle. Frog Human 4 chamber heart with two atria, and two ventricles. Blood is carried to the heart in vessels called veins. Veins from different parts of the body enter the right and left atria. Blood from both atria goes into the ventricle and then is pumped into the arteries, which are blood vessels that carry blood away from the heart. BOTH

Urinary System…you get the idea! Both: consists of the kidneys, ureters, bladder, Remember-The kidneys are organs that excrete urine. Connected to each kidney is a ureter, a tube through which urine passes into the urinary bladder, a sac that stores urine until it passes out of the body. Leaves the frog body through the…. cloaca Leaves the human body through the…. urethra

Digestive System….buuurp! Just like us, when a frog eats the food will pass through… -a mouth with a tongue that leads to the pharynx, or throat - an esophagus, where swallowed food moves into the stomach - Food then moves in small intestine, where most of the digestion and absorption of food into the bloodstream takes place - Any indigestible materials pass through the large intestine and then into the cloaca

Nervous System Do we have a frog nervous system or do they have a human nervous system? The CNS of the frog consists of the brain, which is enclosed in the skull, and the spinal cord, which is enclosed in the backbone. Nerves branch out from the spinal cord.

Time to cut it out!

Safety 1.You are to wear apron, gloves, and goggles the entire block. 2.You MUST stay in the group you have been assigned the entire block. 3.Only ONE person may use the scalpel at a time. 4.When I say clean up you MUST follow the clean up procedure on the board. 5.You may not PLAY WITH or PUNCTURE the organs in the frog. 6.Once you have cut the frog open you MAY NOT cut it anymore unless permitted 7.If you put yourself or others in danger you WILL be sent to another classroom to do book work and you WILL receive a zero on the lab.

To determine the frog’s sex, look at the hand digits, or fingers, on its forelegs. A male frog usually has thick pads on its "thumbs," which is one external difference between the sexes, as shown in the diagram below. Male frogs are also usually smaller than female frogs. In lab section of notebook draw the differences.

In lab section draw incisions (There will only be three!) Once cut you will pin back flaps to the tray.

After cutting skin…

On paper

Watch a dissection Video of dissection Step by step instructions

1.Place the frog inside the zip lock bag and then place it in the big trash can by the door 2.Remove gloves and place them in the trash can by the door 3.Wash the trays and the dissecting trays and dry them with paper towel 4.Place the dissecting tools inside the “black” container provided 5.Use the wipes to clean goggle 6.Use wipes to clean the table tops 7. Wash your hands at the assigned stations 8.Go through checklist #2