Students examine a preserved frog to identify major external features and internal organs of the digestive, respiratory, circulatory, and excretory systems. The activity builds skill with dissection tools while linking structure to function across body systems.

• Follow instructions provided in the links below.

Frog Dissection | 7th Grade Life Science - Love Them Well:

📄 Frog Dissection Lab - Home Science Tools: https://learning-center.homesciencetools.com/wp-content/uploads/HST-Frog-Dissection.pdf

📄 Frog Dissection - Southern Biological: https://www.southernbiological.com/frog-dissection/?srsltid=AfmBOoraWx0oYl3KzcZfDxEahueCaia9Pczi5jafw13P6lZQBVA620ba

📄 Frog Virtual Dissection - dcc.ilc.org: https://dcc.ilc.org/snc2d/14/the_frog_a_virtual_dissec/the_frog_a_virtual_dissec.html

• Compare male vs. female frogs (size of tympanum vs. eye, presence of testes or ovaries).
• Quantify organ mass or length (e.g., liver lobe mass, small intestine length) and relate to function.
• Trace a food particle’s path through the digestive system and annotate each organ’s role.
• Use a virtual or 3D model alongside the specimen to correlate surface and internal landmarks.
• Relate respiratory surfaces by gently inflating a lung with a pipette bulb (instructor demonstration only).
• Compare amphibian anatomy to a fish or mammal model to highlight evolutionary adaptations.

• Wear gloves and a lab coat; tie back hair and avoid loose sleeves.
• Cut only on the dissecting tray with the specimen resting flat; never cut while holding the specimen.
• Handle scalpels and scissors with care; pass tools handle-first and dispose of blades in approved sharps containers.
• Treat preservatives and tissues as potential irritants; work in a well-ventilated area and avoid skin and eye contact.
• Keep food and drink out of the lab; do not conduct dissections near food preparation areas.
• Disinfect benches and tools before and after the lab; wash hands thoroughly after cleanup.
• Follow institutional rules for biological waste and chemical preservative disposal.
• Provide nitrile gloves for those with latex sensitivity.

• Why are the hindlimbs longer and more muscular than the forelimbs? (They power jumping and swimming, reflecting locomotor demands.)
• What is the function of the tympanic membrane and eustachian tubes? (The tympanum receives sound; the tubes equalize middle ear pressure.)
• Why do frogs have vomerine and maxillary teeth if they swallow food whole? (They help grip prey to prevent escape before swallowing.)
• What roles do the liver and gallbladder play in digestion? (The liver produces bile; the gallbladder stores and concentrates bile for fat emulsification.)
• Why are the fat bodies prominent in some specimens? (They store energy for reproduction and overwintering; size varies with season and sex.)
• How does the three-chambered frog heart affect circulation compared to a four-chambered mammalian heart? (Partial mixing of oxygenated and deoxygenated blood can occur, reducing separation of circuits.)
• Where is gas exchange accomplished, and how is it adapted to amphibian life? (In lungs and across moist skin; cutaneous respiration supplements lung function.)
• What structural features increase digestive surface area? (Villi and length of the small intestine increase absorptive area.)
• How does the cloaca differ from separate openings in many mammals? (It is a common exit for digestive, urinary, and reproductive systems.)
• Which observed structures best illustrate hierarchical organization from cells to systems? (Tissues forming organs like liver or lungs, integrated into digestive and respiratory systems.)