Male Frog Dissection
Members: Sunita Gurung
Maymun Mohamud
Halima Jama
Date: June 18, 2025
Introduction
Dissections are a key part of studying
biology as they help students understand
the anatomy of living organisms. Frogs are
commonly used because their organ
systems are similar in layout and function
to those of humans. This similarity allows
students to draw comparisons between
species and gain a deeper understanding
of how body systems work.
This lab focused on examining the internal
and external anatomy of a male frog. Key
objectives included identifying and
understanding the structure and function
of organs such as the heart, liver, lungs,
digestive system, and reproductive
organs.
The purpose of this dissection was to
observe the internal organ systems of a
male frog to better understand how
vertebrate organs are structured and
function together to support life.
Materials Used:
• Preserved frog specimen
• Dissection tray
• Scalpel
• Dissection pins
• Lab worksheet or guide
• Gloves and lab coat
Procedure:
The dissection was carried out in a
controlled and ethical manner using
proper lab safety equipment. The
preserved frog specimen was placed on its
back (ventral side up) in the dissection tray
and pinned at the limbs for stability.
Using a scalpel, a midline incision was
made from the lower abdomen to the
chest. The skin and underlying muscle
layers were carefully cut and pinned back
to expose the internal organs. Each organ
was observed and identified, including the
heart, liver, lungs, stomach, intestines,
kidneys, and testes. Care was taken to
avoid damaging the organs during
dissection.
Results and observations
The following organs were observed:
• Liver: A large, dark brown, three-lobed organ located beneath the heart.
• Heart: A small, triangular organ with three chambers—two atria and one ventricle.
• Lungs: Two small, spongy sacs located under the liver.
• Stomach: A curved organ leading into the small intestine.
• Small and Large Intestines: Long, coiled structures involved in digestion and
waste removal.
• Testes: Small, white, bean-shaped structures near the kidneys, confirming the frog
was male.
• Fat bodies: Yellow, finger-like projections used for energy storage.
• Mesentery: thin transparent membrane, support and attachment, nutrient absorb,
blood supply, fat storage and organ positioning.
• Skin: respiration, thermoregulation, and defense.
• Bladder: storage, water balance, hormonal control, excretion.
• Gallbladder: usually bluish green, moderately full of bile, pear-shaped, flabby and
is easily observed when the abdomen is opened.
No abnormalities were noted; the organs appeared to be well-preserved and clearly
identifiable.
Discussion & Analysis
This dissection helped us understand the internal anatomy of frogs and how their organs
function similarly to those in humans. The liver, which produces bile and helps detoxify
blood, was one of the largest organs observed. The gallbladder stores bile and releases it
into the small intestine for fat digestion.
The frog’s heart has three chambers—this is less efficient than the human four-chambered
heart but sufficient for amphibians. Blood enters the right atrium from the body
(deoxygenated), and the left atrium from the lungs (oxygenated). The single ventricle pumps
the mixed blood to both the lungs and body.
The respiratory system includes lungs and skin. Frogs can breathe through their skin when
underwater, which is a key adaptation for amphibians.
The digestive organs work in sequence: food passes from the mouth to the stomach, then to
the small intestine (nutrient absorption), and finally the large intestine (water reabsorption
and waste removal).
Reproductive and excretory systems meet at the cloaca, a shared exit point. Testes produce
sperm. Kidneys filter waste from the blood, and the bladder stores liquid waste.
This dissection helped us appreciate the complexity of organ systems and how they work
together, reinforcing theoretical learning with hands-on experience.
Conclusion
The male frog dissection allowed us to visually explore and understand the structure and
function of various internal organs. We successfully identified systems responsible for
circulation, respiration, digestion, reproduction, and excretion. This hands-on experience
deepened our understanding of vertebrate anatomy and how similar biological systems
function across species.
References
• Campbell, N. A., & Reece, J. B. (2008). Biology (8th ed.). Pearson Education.
• Ontario Curriculum, Grade 11 Biology SBI3C.
• Biology Corner. (2022). Frog Dissection Guide. www.biologycorner.com
