Biology I

Name: Caitlin HueckstaedtHour: 3 Date: 3/17/14

/45 Points

Lab Due Date:

Written Exam Date:

Practical Exam Date:

Dissection Terms: (use operation frog()

(2 Points)

Anterior = Front Posterior = Back

Dorsal = Top/topside Ventral = bottom/undersideIntroduction:

Frogs belong to the Class Amphibia. Amphibians have adaptations for living in terrestrial as well as aquatic environments. Frogs are among the most commonly studied organisms in biology. Although many differences exist between humans and frogs, the basic body plans are similar. Humans and frogs both belong to the Phylum Chordata. By studying the anatomy of the frog, you will be better able to understand your own body. In this investigation, you will examine the external features of a frog and identify parts of its external anatomy. In addition, you will dissect a preserved frog to observe its internal anatomy.

Materials (per group):

Preserved frog

Dissecting tray

Scissors

Probe

Forceps

Plastic bag

Scalpel

Dissecting pins

Eyedropper

Paper towels

Soap

Gloves

Safety:

Be careful when handling sharp instruments. Gloves should be worn whenever there is physical contact with the frog. Goggles should be worn at all times. Follow your teacher's directions and all appropriate safety procedures when handling specimens.

CAUTION: To avoid injury, cut in a direction away from your hands and body.

DAY 1: External Anatomy of the Frog

1. Obtain a preserved frog, rinse the frog in the sink, and place it in a dissecting tray.

2. Label the following dissecting terms on the diagram below: (2 Points) dorsal surface

ventral surface

anterior end

posterior end

4.

1. Posterior End2. Anterior End

3. Ventral Surface

4. Dorsal Surface

5. Webbed Foot

6. Upper Arm

7. Forearm

8. Tympanic Membrane

9. Wrist

10. Hand

11. Eye

12. Mouth

13. External Nares

14. Thumb

15. Fore Leg16. Nictating Membrane

17. Hind Leg

18. Thigh

19. Lower Leg

20. Ankle

3. Locate the forelegs and hindlegs. Each foreleg, or arm, is divided into four regions. Starting closest to the body the parts are identified as: upper arm, forearm, wrist, and hand. Each hindleg also has four regions: thigh, lower leg, ankle, and foot. Identify the parts of the forelegs and hindlegs. Examine the hands and feet of the frog. If the thumb is enlarged, the frog is a male.

4. Locate the two large, protruding eyes, lift the lower eyelid using a probe; this lid is called the nictitating membrane. This protects the eye while the frog is under water. Because the membrane is translucent (clear), the frog is able to see under water! (

5. Posterior to each eye is a circular region of tightly stretched skin. This region is the tympanic membrane, or eardrum. Locate the tympanic membranes on both sides of the head. Anterior to the eyes, locate two openings called the external nares (singular, naris), or nostrils.

6. Label the following external structures on the above diagram: (8 Points) foreleg (limb)

upper arm

forearm

wrist

hand

thumb

hind leg (limb)

thigh

lower leg

ankle

webbed foot

tympanic membrane

external nares

eye

nictitating membrane

mouth

7. Hold the frog firmly in the dissecting tray. Using scissors make a small cut at each of the hinged points of the jaw. Open the mouth as much as possible.

8. The tongue is the most noticeable structure in the mouth. Observe where the tongue is attached and note the two projections at the free end. The frog is attached to the front of the mouth so that the tongue may extend to capture food.

9. At the back of the mouth locate the large horizontal opening, this is the gullet opening. This is where food (usually whole) enters the digestive system via the esophagus. Ventral to the gullet opening, find a vertical slit, the glottis. The glottis allows air to travel to the lungs via the trachea even when the frog is eating.

10. Look for two openings on the back sides of the floor of the mouth. These are the openings to the vocal sacs. They are present in male frogs but not in female frogs.

11. Examine the roof of the mouth. Near the front center of the roof of the mouth are two small bumps. These bumps are the vomerine teeth. On either side of the vomerine teeth are the openings of the internal nares. Posterior to the vomerine teeth, observe two large bulges. These bulges are the eye sockets. Run your fingers along the edge of the top jaw. The teeth you feel are the maxillary teeth. Frogs do not usually chew their prey, but instead swallow them whole. The openings on either side near the back of the mouth are the Eustachian tubes. This tube leads to the tympanic membrane. This equalizes pressure in the frog's head when it dives under water.

12. In the figure below, label the following parts of the frog's mouth: (5 Points) vomerine teeth

internal nares

maxillary teeth

eye socket

openings to Eustachian tubes

tongue

gullet opening

glottis opening

openings to vocal sacs

palate

Day 1 Questions: Answer the following after completing Day 1 of Lab. (6 Points)

1. Describe the color of the dorsal and ventral surfaces of the frog. 2. How many digits are on each of the frog's hands? Four Digits3. How many digits are on each of the frog's feet? Five Digits4. Is your frog a male or a female? Male. How can you tell? The thumbs are enlarged.5. Where is the nictitating membrane attached?To the bottom of the eye.6. Where is the tongue attached in the mouth? To the anterior of the jawDAYS 2 AND 3: Internal Anatomy of the Frog

1. Place your preserved frog in a dissecting tray with the ventral surface up. With dissecting pins, securely pin the frog's feet and hands to the bottom of the dissecting tray as shown below. Angle the pins away from the body of the frog so they will not interfere with your dissection.

2. With forceps, lift the loose skin of the abdomen. Carefully insert the tip of a pair of scissors beneath the skin. Cut the skin along dotted lines as shown.3. With your fingers, carefully separate the skin from the underlying muscles. Open the flaps of skin as far back as possible and pin them to the bottom of the dissecting tray. Angle the pins away from the body of the frog so they will not interfere with your dissection. Notice the blood vessels branching throughout the inner lining of the skin. Observe the abdominal and pectoral muscles. Note the direction of the muscle fibers.

4. Carefully lift the abdominal muscles with the forceps. NOTE: Keep the cut through the muscles shallow so as not to damage underlying organs. As the incision is made in the chest, or pectoral area, you will need to cut through bone. The bone is part of the pectoral girdle. NOTE: Use extra force with the scissors when cutting through the bone. Be careful not to damage any of the internal organs below the bone.

5. Remove the pins holding the skin in place. Stretch the abdominal opening as much as possible. At this time the hands and feet of the frog may need to be repined. Study the positions of the exposed organs. Notice that most of the organs are held in place by thin, transparent tissues called mesenteries.

6. If the frog is a mature female, the most obvious organs will be the ovaries. The ovaries are white sacs swollen with tiny black-and-white eggs. Carefully lift the ovaries from the body cavity, cut the attachments with scissors, and remove the ovaries from the frog. NOTE: Be careful not to rupture the ovaries with scissors. If the ovaries are ruptured, they can spill a mess of eggs.

7. The large reddish-brown organ in the upper part of the abdominal cavity is the liver. The liver produces a compound called bile which helps digest fats.

8. With a probe, lift and separate the lobes of the liver upward. Behind the middle lobe, look for a greenish, pea-shaped gland. This gland is the gallbladder. The gallbladder stores bile that has been produced by the liver.

DIGESTIVE SYSTEM

9. Locate the esophagus, which is a white tube leading from the mouth and connecting to the upper part of the white, muscular stomach. Notice the shape of the stomach. (J) Look for a constriction at the lowest part of the stomach. This constriction is the pylorus. The pylorus leads into the long, coiled small intestine. Pull (not remove) the loops of small intestine away from the body. Notice the mesentery that holds the intestines in place. Inside the first loop of the small intestine near the stomach, locate a thin, tan colored organ called the pancreas, The pancreas secretes digestive enzymes into the small intestine. Also in the intestinal mesentery, locate a brown bean-shaped organ called the spleen. The spleen filters things like bacteria out of the blood. NOTE: The spleen is an organ of the circulatory system.

10. The small intestine ends in a large bag-shaped organ, the large intestine. The large intestine, or colon, absorbs water and minerals from digested food. The last organ of the digestive system is the cloaca, a saclike organ at the end of the large intestine. Undigested food leaves the frog's body through an opening called the anus.

11. Label the following parts of the digestive system and related organs: (5 Points) stomach

small intestine

large intestine

cloaca

liver

gallbladder

pancreas

anus

spleen

1. Liver2. Spleen

3. Small Intestine

4. Gallbladder

5. Pancreas

6. Stomach

7. Large Intestine

8. Cloaca

9. AnusUROGENITAL SYSTEM

12. The reproductive system and the urinary system of the frog are closely connected and can be studied as the combined urogenital system. The two kidneys are reddish-brown organs located on the dorsal posterior wall of the abdominal cavity. The kidneys lie on either side of the backbone. The kidneys remove wastes from and regulate fluid balance in the blood. NOTE: The kidneys may be covered, with a thin membrane. If so, carefully tear open the membrane with the point of a dissecting needle. The yellow, fingerlike structures are the fat bodies. Fat bodies store energy for hibernation. A small, twisted tube called the ureter leads from each kidney into the saclike urinary bladder. The urinary bladder temporarily stores urine. The urinary bladder is connected to the cloaca. The cloaca collects urine, feces, eggs and sperm before they leave the body.

13. Locate the reproductive organs of the frog. If your frog is a male, it possesses testes, tiny white or yellow organs found on the ventral surface of the kidneys.

14. If your frog is a female, it possessed egg-filled ovaries that were removed earlier. If your frog is an immature female, the pale, empty ovaries are located ventral to the kidneys. Leading from each ovary is a long, coiled tube called the oviduct. The oviduct eventually joins the cloaca.

15. Label the following parts of the male AND female urogenital systems: (7 Points) kidney

fat body

ureter

urinary bladder

cloaca

testes

ovary w/ eggs

oviduct

10.1. Fat bodies

2. Testes

3. Cloaca

4. Kidney

5. Urniary Bladder

6. Ureter

7. Ovary w/ eggs

8. Oviduct9. Fat Body

10. Oviduct

11. Kidney

12. Ureter

13. Cloaca

14. Urinary BladderRESPIRATORY SYSTEM

16. Locate the two lungs. They are small, spongy brown sacs that lie to the right and left of the heart. Look for the bronchial tubes that extend from the anterior part of the lungs and join with the trachea, or windpipe.

17. Insert an eye dropper into the glottis of the frog. Pump air into the lungs and observe.

CIRCULATORY SYSTEM

18. Locate the heart. The heart is encased in a membranous sac called the pericardium. With the tip of the scissors, carefully cut open the pericardium. Note the vessels attached to the heart. 19. If there is time: Remove the pins from the frog's feet and hands. Cut the skin completely around the upper thigh of one leg, as if cutting off the leg of a pair of pants. With forceps, carefully pull the skin downward to the foot. Expose the thigh muscles, the knee and the calf muscles. Move the lower leg up and down to simulate the leg movement during a jump. Observe the various leg muscles involved in the leg movement.

20. Follow your teacher's instructions for storing the frog for further use or properly disposing of the frog and its parts. Thoroughly wash, dry and put away your dissecting tray and tools. Wash your hands with soap and water.

Day 2 Questions: Answer the following after completing Day 2 of Lab. (5 Points)7. How many lobes does the liver contain?3 Lobes8. What is the shape of the stomach?It is a long tube.9. Describe the mesentery that holds the intestines. A very thin membrane holds the intestines together10. What happens to the lungs when air is pumped into the glottis? Lungs Expand as air is pumped in11. How many chambers does a frog's heart have? 3 Name the chambers: Right Atrium, left atrium, and the ventrical

(5 Points)

OrganWhat does it look like?What does it do?

TYMPANUMdetect vibration for hearing

VOMERINE TEETH2, hold prey in mouth

MAXILLARY TEETHrow, chew prey if needed

GULLETopening for food; lead to esophagus

GLOTTISopening for air; lead to trachea

STOMACHdigest and break food apart

TONGUEused to catch prey; attached??

HEART3 chambers; pumps blood; closed

LUNGSexchange gas (O2 and CO2)

LIVERfilter blood and produce bile

GALL BLADDERstores bile

SPLEENproduce and store blood

KIDNEYSproduce urine

SMALL INTESTINEdigest food and absorb nutrients

LARGE INTESTINEdigest food and absorb water

CLOACAhold and release waste/gametes

TESTESproduce sperm

OVARIESproduce ova (eggs)

URETERcarry urine to bladder

FAT BODIESstore energy for hibernation

NICTITATING MEMBRANEprotect eye (goggles)

EUSTACHIAN TUBESinvolved in hearing

INTERNAL NARESaid in detection of prey

These are the words you will need to know for the practical exam. Study every night, spelling counts! During lab, check off the boxes once you can identify each part.

1. Ventral

2. Dorsal

3. Anterior

4. Posterior

5. Thumb

6. Wrist

7. Hand

8. Upper Arm

9. Fore Leg

10. Thigh

11. Lower Leg

12. Ankle

13. Webbed Foot

14. Hind Leg

15. Eyes

16. Head

17. Throat

18. Thorax

19. Abdomen

20. Nictitating Membrane

21. Tympanum

22. External Nares (Nostril)

23. Vomerine Teeth

24. Maxillary Teeth

25. Internal Nares

26. Eye Socket

27. Palate

28. Gullet

29. Glottis

30. Eustachian Tube Opening

31. Tongue

32. Heart (2 atria 1 ventricle)

33. Stomach

34. Lungs

35. Liver

36. Gall Bladder

37. Spleen

38. Kidneys

39. Small Intestine

40. Large Intestine

41. Cloaca/ Anus

42. Testes

43. Oviduct

44. Ovaries

45. Fat Bodies

46. Ureter (*may not see)

Special Notes for Practical Day:

Get lots of sleep the night before

Dont leave any blanks

Write hints to yourself in the margin

i.e. the greenish organ, looks like a pea (for when you have time at later stations)

Nothing on the practical exam repeatsLiver

Gall Bladder

Lungs

Stomach

Large Intestine

Small Intestine

Spleen

Kidney

Pancreas

Fat Bodies

Heart

Ovary

Oviduct

Testes

1. Put your dissection pan/kit # and Names/Hour on your lab & bag.

2. Wear goggles/glasses at all times.

3. Wear gloves when touching the frog.

4. Wash and label your gloves & place in specimen bag each day (same gloves for 4 days).

5. Wrap your frog in a paper towel, run under water, & put in bag each day.

6. Points will be deducted for areas/equipment not cleaned or put away properly.

7. Inappropriate behavior will result in removal from lab. A zero for that, and each remaining, day will be recorded. You will learn the frog on your own time.

8. Study/Review notes, lab, operation frog, & froguts.com EVERY DAY!

9. Have a goal each day. (Today = 1-22 on Kermit Study Guide)

10. Form study groups before/after school(

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7. Internal nares

8. Vomerine Teeth

9. Openings to Eustachinan tubes

10. Openings to vocal Sacs

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