Name(s): ______Date:______Earthworm Dissection External Anatomy Examine your earthworm and determine the dorsal and ventral sides. Locate the two openings on the ventral surface of the earthworm. Locate the openings toward the anterior of the worm which are the s perm ducts. Locate the openings near the clitellum which are the g enital setae. Locate the dark line that runs down the dorsal side of the worm, this is the d orsal blood vessel. The v entral blood vessel can be seen on the underside of the worm, though it is usually not as dark. Locate the worm’s anus on the far posterior end of the worm. . Note the swelling of the earthworm near its anterior side - this is the c litellum. Label the earthworm pictured. A______B ______C ______D ______Internal Anatomy 1. Place the specimen in the dissecting pan D ORSAL side up. 2. Locate the clitellum and insert the tip of the scissors about 3 cm posterior. 3. Cut carefully all the way up to the head. Try to keep the scissors pointed up, and only cut through the skin. 4. Spread the skin of the worm out, use a teasing needle to gently tear the s epta (little thread like structures that hold the skin to organs below it) 5. Place pins in the skin to hold it apart – set them at an angle so they aren’t in the way of your view.

Reproductive System The first structures you probably see are the s eminal vesicles. They are cream colored and located toward the anterior of the worm. These are used for producing sperm. U se tweezers to remove these white structures from over the top of the digestive system that lies underneath it.

Circulatory system The d orsal blood vessel appears as a dark brownish-red vessel running along the intestine. The h eart (or aortic arches) can be found over the esophagus (just posterior to the pharynx). Carefully tease away the tissues to expose the arches of the heart. How many arches can you count? ______The v entral blood vessel is opposite the dorsal blood vessel, and cannot be seen at this time because the digestive system covers it, find the ventral blood vessel on your worm. Label the diagram using the bold words in the section above.

www.biologycorner.com Digestive System The digestive system starts at the mouth. You will trace the organs all the way to the anus and identify each on the worm.

Find the mouth opening, the first part after the mouth is the pharynx, you will see stringy things attached to either side of the pharynx (pharyngeal muscles). The esophagus leads from the pharynx but you probably won’t be able to see it, since it lies underneath the heart. You will find two structures close to the clitellum. First in the order is the crop, followed by the gizzard. The gizzard leads to the intestine, which is as long as the worm and ends at the anus.

Use your scissors to cut open the crop and gizzard. Which one has the harder exterior ______

Nervous System Locate the brain in the far anterior region of the worm. It is very tiny and whitish colored. If you can’t find it, it is probably because it was destroyed when you cut the worm. You CAN locate the ventral nerve cord by removing the intestines and searching for the white string-like structure that runs the length of the worm. Remove the intestine and locate the ventral nerve cord.

Lab Analysis (a nswer True or False) 1. ____ The brain attaches to the ventral nerve cord. 2. ____ The dorsal side of the worm is lighter than the ventral side.. 3. ____ The clitellum is located toward the anterior end of the worm. 4. ____ The esophagus lies beneath the pharynx 5. ____ Earthworms are hermaphrodites. 6. ____ The ventral nerve cord and the ventral blood vessel are connected. 7. ____ The pale string-like structure running the length of the ventral side of the worm is the blood vessel. 8. ____ An earthworm has fourteen aortic arches. 9. ____ The dorsal blood vessel can be seen from the worm’s exterior. 10. ____ Seminal vesicles are part of the worm’s digestive system.

Label the image.

www.biologycorner.com 4/22/2020 Frog Dissection Coloring

Name: ______Date:______Frog Dissection Coloring

When the abdominal cavity of the frog is opened, many organs of the digestive and urogenital systems can be observed. As you read the descriptions of the organs below, color them on the diagram.

1. Leading from the mouth is a tube that connects to the stomach. Color the esophagus pink.

2. The largest organ is the liver, and it consists of multiple lobes. Color the right lobe (a) light brown. Color the left anterior lobe (b) medium brown, and the left posterior (c) lobe dark brown. The liver has several jobs related to digestion and detoxification.

3. Tucked under the liver is the gall bladder, which stores bile that is produced by the liver. color the gall bladder green and the bile duct (3b) a darker green.

4. The gall bladder connects to the duodenum of the small intestine. Color the duodenum light blue.

5. The duodenum connects to the curly part of the small intestine known as the ileum. The ileum is where nutrients are absorbed into the blood. Color the ileum dark blue.

6. The spleen is an organ that has an immune function and is found within the coils of the intestine. Color it red.

7. The ileum connects to the large intestine and the cloaca. Water is reabsorbed in the large intestine and wastes are stored at the cloaca before exiting the anus. Color this area orange.

8. At the lowest part of the abdominal cavity is a thin pouch for storing urine. Color the bladder yellow.

9. The stomach can be viewed if you lift the liver and is often curved, this is the first site of chemical digestion in the frog. Color the stomach orange.

10. Within the curve of the stomach is a gland called the pancreas. The pancreas is involved in the digestion and the uptake of sugars. Color the pancreas yellow.

11. The coils of the small intestine are held together by a thin membrane called the mesentery. Color it pink.

12. A female frog will have tiny curling tubes deep in the abdominal cavity that carry eggs. Color the oviducts red.

13. Also deep within the cavity are bean shaped organs, the kidneys which filter wastes from the blood, creating urine which is then stored in the bladder. Color the kidney gray.

14. Task – after reading the descriptions, write down the structure based on the description. Use the bold words above.

______Carries eggs in female frogs

______First site of chemical digestion

______Stores solid waste, eggs, sperm

______Filters blood, makes urine

______Digestion, uptake of sugar

______Holds the coils of small intestine

______Stores urine

______First part of the small intestine

______Stores Bile

15. Task - COLOR the frog according to the directions and LABEL each structure next to the number.

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https://www.biologycorner.com/worksheets/frog-dissection-coloring.html 2/2 4/22/2020 Frog Dissection Crossword

Name:______Frog Dissection Crossword

ACROSS DOWN 1. Membrane that covers the eye 4. Opening in the mouth, airway 2. Can be large or small, helps digest food 7. Tubes that equalize pressure to the eardrum 3. The largest organ in the frog's body cavity, having 3 8. Regulates food exiting the stomach, pyloric ______lobes valve 4. The opening where waste, eggs, and sperm exit 10. System that includes the stomach and intestines 6. Located underneath the liver; _____ bladder 14. The very first stretch of the small intestine 9. Long tube that runs around the kidneys, carries eggs in 16. The esophagus leads to this structure females 17. Membrane that functions as an eardrum 11. The lower (single) chamber of the frog's heart 19. Located above the kidneys, but only in male frogs 12. Used to capture food, attaches to the front of the 20. Teeth at the roof of the mouth mouth 21. Spiderweb-like membrane that covers the heart and 13. Stores urine; urinary ______other organs 15. Opening in the mouth where food enters 18. Famous from from the Muppets

https://www.biologycorner.com/worksheets/frog_dissection_crossword.html 1/1 4/22/2020 Student Guide to the Frog Dissection

Name: ______

Student Guide to the Frog Dissection Dissection Instructions

1. Place the frog in the dissecting pan ventral side up. 2. Use scissors to lift the abdominal muscles away from the body cavity. Cut along the midline of the body to the forelimbs. 3. Make transverse (horizontal) cuts near the arms and legs. 4. Life the flaps of the body wall and pin back.

*If your specimen is a female, the body may be filled with eggs. You may need to remove these eggs to view the organs.

Locate each of the organs below. Check the box to indicate that you found the organs.

1. Fat Bodies --Spaghetti shaped structures that have a bright orange or yellow color, if you have a particularly fat frog, these fat bodies may need to be removed to see the other structures. Usually they are located just on the inside of the abdominal wall.

2. Peritoneum A spider-web like membrane that covers many of the organs, most easily seen covering the heart.

3. Liver--The largest structure of the the body cavity. This brown colored organ is composed of three lobes. The right lobe, the left anterior lobe, and the left posterior lobe. The live secretes a digestive juice called bile which is needed for the proper digestion of fats.

4. Heart - at the top of the liver, the heart is a triangular structure. The left and right atrium can be found at the top of the heart. A single ventricle located at the bottom of the heart. The large vessel extending out from the heart is the conus arteriosis.

5. Lungs - Locate the two spongy lungs by looking behind the heart and liver..

6. Gall Bladder --Lift the lobes of the liver, there will be a small green sac under the liver. This is the gall bladder, which stores bile. (hint: it kind of looks like a booger)

7. Stomach--Curving from underneath the liver is the stomach. The stomach is the first major site of chemical digestion. Frogs swallow their meals whole. Follow the stomach to where it turns into the small intestine. The pyloric sphincter valve regulates the exit of digested food from the stomach to the small intestine.

8. Pancreas - This structure is located on the inside curve of the stomach. It it a gland that often falls apart during the preserving process so it many not be visible on your frog.

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9. Small Intestine--Leading from the stomach. The first straight portion of the small intestine is called the duodenum, the curled portion is the ileum. The ileum is held together by a membrane called the mesentery. Note the blood vessels running through the mesentery, they will carry absorbed nutrients away from the intestine. Absorption of digested nutrients occurs in the small intestine.

10. Large Intestine--As you follow the small intestine down, it will widen into the large intestine. The large intestine leads to the cloaca, which is the last stop before solid wastes, sperm, eggs, and urine exit the frog's body. (The word "cloaca" means sewer.) The opening to the outside of the doy is the anus.

11. Spleen--Return to the folds of the mesentery, this dark red spherical object serves as a holding area for blood.

12. Esophagus--Return to the stomach and follow it upward, where it gets smaller is the beginning of the esophagus. The esophagus is the tube that leads from the frogs mouth to the stomach. Open the frogs mouth and find the esophagus, poke your probe into it and see where it leads.

STOP! If you have not located each of the organs above, do not continue on to the next sections!

Removal of the Stomach: Cut the stomach out of the frog and open it up. You may find what remains of the frog's last meal in there. Look at the texture of the stomach on the inside.

What did you find in the stomach?

Measuring the Small intestine: Remove the small intestine from the body cavity and carefully separate the mesentery from it. Stretch the small intestine out and measure it. Now measure your frog. Record the measurements below in centimeters. Frog length: ______cm Intestine length ______cm Urogenital System

The frog's reproductive and excretory system is combined into one system called the urogenital system. You will need to know the structures for both the male and female frog

Kidneys - flattened bean shaped organs located at the lower back of the frog, near the spine. They are often a dark color. The kidneys filter wastes from the blood. Often the top of the kidneys have yellowish stringy fat bodies attached.

Testes - in male frogs, these organs are located at the top of the kidneys, they are pale colored and roundish. Oviducts - females do not have testes, though you may see a curly structure around the outside of the kidney, these are the oviducts. Oviducts are where eggs are produced. Males can have structures that look similar, but serve no actual purpose. In males, they are called vestigial oviducts.

Bladder - An empty sac located at the lowest part of the body cavity. The bladder stores urine.

Cloaca - mentioned again as part of the urogenital system - urine, sperm and eggs exit here.

Label the parts of the urogenital system. https://www.biologycorner.com/worksheets/frog-dissection.html 1/3 4/22/2020 Student Guide to the Frog Dissection

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Name: ______

Post Lab Questions

1. The membrane holds the coils of the small intestine together: ______2.This organ is found under the liver, it stores bile: ______3. Name the 3 lobes of the liver: ______, ______, ______4. The organ that is the first major site of chemical digestion: ______5. Eggs, sperm, urine and wastes all empty into this structure: ______6. The small intestine leads to the: ______7. The esophagus leads to the: ______8. Yellowish structures that serve as an energy reserve: ______9. The first part of the small intestine(straight part): ______10. After food passes through the stomach it enters the: ______11. A spiderweb like membrane that covers the organs: ______12. Regulates the exit of partially digested food from the stomach: ______13. The digestive system ends at the opening called the:______14. Organ found within the mesentery that stores blood: ______15. The largest organ in the body cavity: ______

Label the Diagram

A. ______B. ______C. ______D. ______E. ______F. ______G. ______H. ______I. ______J. ______K. ______L. ______M. ______N. ______P. ______

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Frog Dissection: External Anatomy

1. Observe the dorsal and ventral sides of the frog. Dorsal side color ______Ventral side color ______

2. Examine the hind legs. How many toes are present on each foot? ______Are they webbed? _____ 3. Examine the forelegs. How many toes are present? ______Are the toes webbed? ______4. Use a ruler to measure your from the tip of the head to the end of the frog's backbone. Compare the length of your frog to other frogs Your Frog (cm) Frog 2 Frog 3 Frog 4 Frog 5 Average Length

5. Locate the frog's eyes, the nictitating membrane is a clear membrane that attached to the bottom of the ​ ​ eye. Use tweezers to carefully remove the nictitating membrane. You may also remove the eyeball. What color is the nictitating membrane? ______What color is the eyeball? ______

6. Just behind the eyes on the frog's head is a circular structure called the tympanic membrane. The ​ ​ tympanic membrane is used for hearing. Measure the diameter (distance across the circle) of the tympanic membrane. Diameter of tympanic membrane = ______cm

7. Feel the frog's skin. Is it scaley or is it slimy? ______

Anatomy of the Frog's Mouth Procedure: Pry the frog's mouth open and use scissors to cut the angles of the frog's jaws open. Cut deeply so that the frog's mouth opens wide enough to view the structures inside.

1. Locate the tongue. Play with the tongue. Does it attach to the front or the back of the mouth? ______​ ​ (You may remove the tongue). Draw a sketch of the tongue, paying attention to its shape. Tongue Sketch:

2. In the center of the mouth, toward the back is a single round opening, the esophagus. This tube leads to ​ ​ the stomach. Use a probe to poke into the esophagus.

3. Close to the angles of the jaw are two openings, one on each side. These are the Eustachian tubes. They ​ ​ are used to equalize pressure in the inner ear while the frog is swimming. Insert a probe into the Eustachian tube. To what structure does the Eustachian tube attach? ______

www.biologycorner.com 4. Just behind the tongue, and before you reach the esophagus is a slit like opening. (You may need to use your probe to get it to open up). This slit is the glottis, and it is the opening to the lungs. The frog breathes and ​ ​ vocalizes with the glottis. Use your probe to open the glottis and compare that opening to the esophagus.

5. The frog has two sets of teeth. The vomerine teeth are found on the roof of the mouth. The maxillary teeth ​ ​ ​ are found around the edge of the mouth. Both are used for holding prey, frogs swallow their meals whole and do NOT chew. Run you finger over both sets of teeth and note the differences between them.

6. On the roof of the mouth, you will find the two tiny openings of the nostrils, if you put your probe into those ​ ​ openings, you will find they exit on the outside of the frog.

7. Label the structures

8. Complete the table. Structure Function Location

Vomerine Teeth

Eustachian Tubes

Tympanic Membrane

Esophagus

Glottis

Tongue

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