Frog Dissection Guidelines

INSTRUCTIONS FOR DISSECTION: THIS IS THE ONLY SPECIMEN YOU AND YOUR PARTNERS WILL GET. DO NOT MUTILIATE YOUR SPECIMEN, AS IT WILL SERVE AS A STUDY GUIDE! REMEMBER: Dissection is not just cutting and slicing. Except for major incisions, such as removing layers of skin and muscle to open the body cavity, dissection is NOT cutting. Rather, it is making careful incisions to expose organs and then using a probe to separate various structures. The intent is to carefully unwrap the organism’s structures without damaging them.REMEMBER: Dissection is not just cutting and slicing. Except for major incisions, such as removing layers of skin and muscle to open the body cavity, dissection is NOT cutting. Rather, it is making careful incisions to expose organs and then using a probe to separate various structures. The intent is to carefully unwrap the organism’s structures without damaging them. Make sure you keep your specimen moist when it is not in use. If you let it dry out, it gets foul and nasty, grows fungus, becomes a biohazard and is no longer good for studying. Wrap it in damp paper towels and store it in the plastic bag provided.Make sure you keep your specimen moist when it is not in use. If you let it dry out, it gets foul and nasty, grows fungus, becomes a biohazard and is no longer good for studying. Wrap it in damp paper towels and store it in the plastic bag provided. Complete the packet/chart. Anything in the packet is fair game for the test. You will be given a lab practical test over the dissection portion of the unit. This will not only cover the written material from the systems test but will also include the dissection unit.Complete the packet/chart. Anything in the packet is fair game for the test. You will be given a lab practical test over the dissection portion of the unit. This will not only cover the written material from the systems test but will also include the dissection unit.

Dissection Directions Observe the external features of the frog. Observe the external features of the frog. Use the illustrations to locate all external features. Use the illustrations to locate all external features. Determine if the frog is male or female Determine if the frog is male or female Place frog so that its ventral (abdomen) surface is facing up. Place frog so that its ventral (abdomen) surface is facing up. Use scissors to make small incisions in the corners of the mouth, where the upper and lower jaws are joined at a hinge joint. Use scissors to make small incisions in the corners of the mouth, where the upper and lower jaws are joined at a hinge joint. Pry the mouth open as wide as possible and locate the structures indicated by your teacher. Use the pictures and illustrations as guides. Pry the mouth open as wide as possible and locate the structures indicated by your teacher. Use the pictures and illustrations as guides

Websites to view dissected frogs (dissection images) (dissection images) ction/frog_dissection.htm (dissection images) ction/frog_dissection.htm (dissection images) ction/frog_dissection.htm ction/frog_dissection.htm (frog reproduction) (frog reproduction) (dissection guide with online test that includes images) Refer to pages for Amphibians Overview

Anterior (Cranial) - toward the head Posterior (Caudal) - toward the tail Lateral - toward the side Dorsal (Superior) - toward the backbone Ventral (Inferior) - toward the belly Directional Terms

Leopard Frog Dissection: Day 1

Nictitating Membrane

Tympanic Membrane

Forelimb

Thigh, Hind Limb, Web

Frog Mouth Structures

Mouth Structures

Mouth Structures

CLEANING UP! Clean up your table by placing your frog into a plastic bag given to you by your teacher. Clean up your table by placing your frog into a plastic bag given to you by your teacher. Write all of your group members’ names on the plastic bag. Take care of this bag! You will be using it for several days. Write all of your group members’ names on the plastic bag. Take care of this bag! You will be using it for several days. PLACE THE BAG IN THE AREA PROVIDED FOR YOUR CLASS BY YOUR TEACHER! PLACE THE BAG IN THE AREA PROVIDED FOR YOUR CLASS BY YOUR TEACHER! Wash your gloves with soap and water, and dry with paper towels. Write your name on the gloves, and place gloves in the designated area for reuse. Wash your gloves with soap and water, and dry with paper towels. Write your name on the gloves, and place gloves in the designated area for reuse. Spray your table with disinfectant and dry with paper towels. Dispose of towels in trashcan. Spray your table with disinfectant and dry with paper towels. Dispose of towels in trashcan. Wash your hands with soap and water. Wash your hands with soap and water.

Leopard Frog Dissection: Day 2

Heart and Liver

Gall Bladder

Stomach, Pancreas, Small Intestine

Spleen, Oviduct, Egg Mass

Pancreas and Fat Bodies

Liver, Small Intestine, Fat Bodies

Stomach and Pancreas

Circulatory System Terminology Pericardium: surrounds & protects the heart Pericardium: surrounds & protects the heart Thymus gland: aids in immunity & produces WBCs Thymus gland: aids in immunity & produces WBCs Atria: 2 top chambers of the heart, receives the blood Atria: 2 top chambers of the heart, receives the blood Ventricles: 2 bottom chambers of the heart, pump blood Ventricles: 2 bottom chambers of the heart, pump blood Septum: separates the right & left sides of the heart Septum: separates the right & left sides of the heart Coronary blood vessels: feeds the muscle of the heart with oxygen Coronary blood vessels: feeds the muscle of the heart with oxygen Aorta: carries oxygenated blood to body Aorta: carries oxygenated blood to body Anterior Vena Cava: carries blood from head to heart (deoxygenated) Anterior Vena Cava: carries blood from head to heart (deoxygenated) Posterior Vena Cava: carries blood from bottom to heart (deoxygenated) Posterior Vena Cava: carries blood from bottom to heart (deoxygenated)

Look at the differences in an amphibian heart. The amphibian heart has only 3 chambers. This allows for only 60% degree of oxygenation of blood in the ventricle.

CLEANING UP! Clean up your table by placing your frog into a plastic bag given to you by your teacher. Clean up your table by placing your frog into a plastic bag given to you by your teacher. Write all of your group members’ names on the plastic bag. Take care of this bag! You will be using it for several days. Write all of your group members’ names on the plastic bag. Take care of this bag! You will be using it for several days. PLACE THE BAG IN THE AREA PROVIDED FOR YOUR CLASS BY YOUR TEACHER! PLACE THE BAG IN THE AREA PROVIDED FOR YOUR CLASS BY YOUR TEACHER! Wash your gloves with soap and water, and dry with paper towels. Write your name on the gloves, and place gloves in the designated area for reuse. Wash your gloves with soap and water, and dry with paper towels. Write your name on the gloves, and place gloves in the designated area for reuse. Spray your table with disinfectant and dry with paper towels. Dispose of towels in trashcan. Spray your table with disinfectant and dry with paper towels. Dispose of towels in trashcan. Wash your hands with soap and water. Wash your hands with soap and water.