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752475-609423004514850-61976000Name: _____________________________________________ Due Date: __________________ Period: ________Check off ScoreTaskSpecial Instructions /5Read and highlight the lab procedures.Highlight structures in one color and underline functions./5Read one of the assigned frog articles. Write a one paragraph summary explaining what the article was about.Include what you think is the most important part of the article./5Label the diagram included in the frog dissection.The names are in the directions. You have highlighted/underlined them./5Complete the chart of functions included in the dissection.Most of the functions are described in the frog dissection. /10Complete the Frog Dissection and the Post-lab questions. Answers each question fully and completely. /10After completing the dissection, write the conclusion.Conclusion needs to be in in 3 paragraphs.Total/40To help you prepare for the dissection and to help you get the most out of it, you will be required to do some independent work. The following is a list of tasks to help you learn about the frog. You must complete each task on the list below. Many of them are just completing the lab sheet. Check off each one as you finish it to help keep track of the assignments you have left to do. External Anatomy1.? Place the frog in the dissecting pan ventral side up. Examine the hind and forelegs. The hind legs are strong and muscular for jumping and swimming. The forelegs provide balance and cushion the frog when it lands after jumping. Notice the toes on each.2.? Locate the large bulging eyes. The frog has 3 eyelids. The two outer ones are the color of the frog’s body and do not move. The third is a transparent membrane that protects the eye while permitting the frog to see under water called the nictitating membrane. It also keeps the eye moist when the frog is on land.3. Behind each eye, find the circular eardrum. This is called the tympanum. 4. Next, locate the two openings into the nasal cavity. These external nares are found toward the tip of the snout, will close when the frog is under water. 5. Feel the frog’s skin. It is smooth, moist and thin. Because the skin is thin and moist, the frog can breathe directly through the skin as well as with its lungs. Turn the frog over to examine its belly. Notice the difference in coloring between the belly and the rest of the frog’s body.6. While the frog is on its back (dorsal side), pry open its mouth, cutting it open at the corners. Locate the tongue. Examine how it is attached in the mouth. In a live frog, the tongue is sticky and is used to catch insects. Gently run your finger along the inside of the upper jaw. The ridges you feel are maxillary teeth, used for grinding and crushing prey. Two vomerine teeth for catching prey can also be found in the upper jaw, between and slightly behind the internal opening of the nostrils.7. Find the glottis (throat), the wide opening that leads to the esophagus. The esophagus transports food from the mouth to the stomach, much like yours does. On both sides of the glottis, near the jaw hinges are the openings to the Eustachian tubes; these tubes are auditory tubes for vertebrates. Gently put your probe in these tubes to see where they lead on the outside of the frog.2562960666150019050-3810Dissection1. Place the frog on its back. Use scissors to lift the abdominal muscle away from the body cavity. Cut along the midline of the body from the pelvic to the pectoral girdle. Follow the diagram on the right. 2. Make transverse (horizontal) cuts near the arms and legs. Lift the flaps of the body wall and pin back. 3. Repeat the cuts you made through the skin, this time cutting through the muscles. Do Not cut too deep or you will damage the organs below. The sternum or breastbone is between the forelegs. Cut through this tough structure and fold back the muscles. Pin to secure.Internal Anatomy If your frog is a female, the body cavity may be full of black eggs and/or ovary tissue. If this is the case, carefully remove this material and rinse the body cavity with water. Your frog should also have fat bodies just under the abdominal wall. They are spaghetti shaped structures that have a bright orange or yellow color. The fat bodies save and store energy that will be used during reproduction. They may be large if your frog is larger.The largest organ in the abdominal cavity is the liver. It is divided into several lobes-count them. The liver has 2 main functions. First, it acts as a filter, removing poisons from the blood. It also produces bile, a chemical that breaks down fats for digestion.Locate the greenish sac attached to the underside of the liver. This is the gallbladder. It stores bile.Posterior (behind) to the liver, find the large white stomach. It will be on the right side as you look at the frog. The stomach is responsible for most of the mechanical breakdown of the food because frog’s teeth only serve to hold prey in the mouth, not to break it apart. The stomach connects to the small intestine, where the nutrients from food are absorbed into the bloodstream to be transported throughout the body. Notice the thin, transparent membranes, called mesenteries that hold the coils of small intestine together.The small intestine eventually widens to form the large intestine. This straight tube leads to the anus and functions to absorb water from waste materials before they leave the body. The very bottom portion of the large intestine is called the cloaca. It is a cavity into which the digestive, urinary and reproductive canals open. This area opens to the outside and materials that are sent here are voided to the outside of the body.Two smaller organs are somewhat difficult to find. In the mesentery, along the inner curve of the stomach, locate the pinkish pancreas. This organ makes insulin which is used by the body to absorb the carbohydrates from food into the blood. Also, in the mesentery see if you can find a small reddish spherical structure. This is the spleen. The function of the spleen is to recycle red blood cells and make white blood cells to fight disease.Locate the lungs, two grayish saclike structures dorsal to the liver (above, towards the head). The lungs take in air and facilitate the diffusion of oxygen in and carbon dioxide out of the blood stream.Locate the heart between the lungs. Cut through the thin membrane that surrounds the heart. This will expose the heart for closer examination. The frog’s heart has 3 chambers. Find the two upper chambers, the left atrium and the right atrium. The right atrium collects the oxygen depleted “blue” blood as it comes back to the heart from the body. The left atrium collects oxygen rich “red” blood flowing back from the lungs. Find the lower ventricle that squeezes the blood out to both the body and the lungs. With the probe, examine these chambers to compare the thickness of the walls.Find the two dark brown kidneys attached to the back wall of the abdominal cavity. Kidneys filter the blood and remove nitrogen wastes (these make up the urine). Find the urinary bladder which holds urine before it empties into the cloaca. The tubes between each kidney and the bladder are called ureters.Using your scissors, carefully remove the liver. Cut through the upper end of the stomach and the lower end of the large intestine. This will allow you to remove the stomach and the intestines. The intestines are the location of nutrient absorption for the frog. How long do you think the small intestine is? Record your guess. Then stretch out the small intestine and measure it. Measure the length of the frog and compare to the length of the intestine-399415121920External 4000020000External Post Lab Questions-7429510160000Describe the structural differences in the toes of the back and forelegs. Why are they different?The frog’s sense organs are on the top of the head. How does this help the frog in the water?Describe the difference in coloration between the belly of the frog and the rest of its body. How does this color adaptation help the frog?Describe the shape of the tongue and how it is attached to the mouth. How does this adaptation help the frog?Where do the Eustachian tubes lead?-37528553340Internal 4000020000Internal -742958128000How many lobes does the liver have?Why is the gall bladder located where it is?Which has thicker walls, the stomach or the small intestine? Explain why.Which has a thicker wall, the ventricle or the atrium? Explain why.The membrane holds the coils of the small intestine together is called the? ________________How long was the small intestine? How does the length relate to its function?Label the DiagramA. __________________________________B. __________________________________C. __________________________________D. __________________________________E. __________________________________F. __________________________________G. __________________________________H. __________________________________I. __________________________________J. __________________________________K. __________________________________L. __________________________________M. __________________________________N. __________________________________26523951848485(membrane)00(membrane)OrganFunctionCloacaEsophagusEustachian tubesFat bodiesGall bladderKidneyLarge IntestineLeft AtriumLiverLungsMesenteriesPancreasRight AtriumSmall intestineSpleenStomachTeeth (maxillary & vomerine)VentricleConclusion: Sum up your work on the frog using the following prompt:3867150863604000020000Paragraph 1:What is a vertebrate?What is an amphibian?Thesis statement (What is this conclusion about?)Paragraph 2:Endo/ectothermicSymmetryOrgans/SystemsMovementParagraph 3:MetamorphosisHow does form fit function in the frog? ................
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