dissection of frog, perch, worm lab.pdf

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Frog Internal AnatomyMs. KiriakopoulosSNC2D1. Place the frog in the dissecting pan on its back (dorsal surface)2. Spread out the limbs3. Use T pins to fasten the frog to the wax in the tray.4. With forceps gently lift the lose skin away from the body Usingscissors, make a small cut in the middle of the abdomen5. Cut along the midline of the body from rear to the head.6. Make transverse (horizontal) cuts near the arms and legs.7. Life the flaps of the body wall and pin back.8. Repeat steps 5-7 but cut through the muscle tissue this timeAnatomy Check ListLocate each of the organs by using the descriptions and pictures.Liver--The largest structure of the body cavity.This brown colored organ is composed of threeparts, called lobes. The liver is not primarily anorgan of digestion; it does secrete a digestive juicecalled bile. Bile is needed for the digestion of fats.Heart - at the top of the liver, the heart is atriangular structure. The left and right atrium can befound at the top of the heart. A single ventriclelocated at the bottom of the heart.Lungs - Locate the lungs by looking underneath andbehind the heart and liver. They are two spongy organs.Gall bladder--Lift the lobes of the liver, there willbe a small green sac under the liver. This is the gallbladder, which stores bile.Stomach--Curving from underneath the liver is the stomach. The stomach is the first major site ofchemical digestion. Frogs swallow their meals whole. Follow the stomach to where it turns into thesmall intestine. You can also open the stomach to see what the frog’s last meal was.Small Intestine--Leading from the stomach, a small curly structure. Pull it out to see how long it is.Eventually it will widen to become the large intestine. Nutrients are absorbed in the small intestine.Large Intestine--As you follow the small intestine down, it will widen into the large intestine. Thelarge intestine is also known as the cloaca in the frog. The cloaca is the last stop before wastes, sperm,or urine exit the frog's body. (The word "cloaca" means sewer.)
Ms. KiriakopoulosSNC2DSpleen--Return to the folds of the mesentery, this dark red spherical object serves as a holding areafor blood, where harmful particles can be filtered out for the immune system.Esophagus--Return to the stomach and follow it upward, where it gets smaller is the beginning of theesophagus. The esophagus is the tube that leads from the frog’s mouth to the stomach. Open the frog’smouth and find the esophagus, poke your probe into it and see where it leads.Analyzing and Interpreting1. How is the mouth specialized in each of the three specimens?2. Explain how the structure of the intestines is related to their role in digestion.3. What is the function of the liver in digestion?4. What is the function of the gall bladder?5. Why do you think the gall bladder is located so close to the liver? Explain your answer.6. Trace the path of food through the digestive tract in the earth worm, frog and perch on aseparate piece of paper.7. Describe one problem that you encountered in performing the dissection and explain how yousolved the problem.8. How is the digestive system of the worm, the perch, and the frog each suited to its habitat?
Page 1 and 2: Name: _____________________________
Page 3: Ms. KiriakopoulosSNC2D11.Lift the f

dissection of frog, perch, worm lab.pdf

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