Frog Anatomy
What is inside a frog?

If you could UNZIP a frog,
from tummy to chin
and look inside . . . Go to next page Your innards are rather similar. Its insides would look
something like this. There's a LOT
of stuff crowded together
inside that frog!
What does it all actually
DO? Let's find out. Begin with the Digestive System After a frog captures
an insect with its tongue

and uses its eyeballs
to swallow the insect whole

and pushes it down
its esophagus

WHERE DOES IT GO? Frogs eat a live prey which travels
down its esophagus into the STOMACH.
The prey dies by drowning or suffocating in stomach acids. The food goes through the small intestine,
where it is broken down and absorbed. The rest is excreted out
the frog's cloaca, as solid feces. What isn't absorbed enters the colon
or large intestine, where water is removed. small
intestines It Goes Through the stomach large
intestines esophagus cloaca Digestive System Now locate these parts of the


inside the frog. Colon Small Intestines Stomach Cloaca DIGESTIVE SYSTEM Click on the frog's stomach. A frog uses its stomach to store food.

A frog has no lower teeth to chew its food prior to digestion.
So captured prey is swallowed largely whole and often still alive! The prey travels down the frog's esophagus and enters the stomach still squirming. There the prey is stored and eventually dies either by suffocation or drowning.

The frog's stomach begins digestion by adding in digestive juices. The twenty-four hour journey through the frog's DIGESTIVE tract begins -- unless, of course, the frog's meal crawls back up the frog's gullet and out of its mouth!

Frogs cannot vomit. So if they eat something toxic or too large, many species of adult frogs will EJECT their ENTIRE STOMACH. They turn it inside out and wipe the unwanted contents away with their front legs!
Click on the
question mark
for the answer. Yes!
Stomach What does the stomach do Click on the frog's
small intestine. The frog's small Intestine breaks down (digests) most of the food the frog eats. It uses digestive enzymes and acids to dissolve the frog's meal. It is through the small intestine that most of the digested nutrients are absorbed into the frog's blood stream.

The length of a frog's coiled up intestine is about ten times the length of its whole body! This length allows the frog to have more time to fully digest and absorb the nutrients from its prey. Click on the
question mark
for the answer. Yes!
Small
Intestine What does the small intestine do Click on the frog's colon. The colon or large intestine stores the undigested food coming out of the small intestine. The colon absorbs water, salt and the remaining nutrients from the leftover food waste.

The colon moves the nearly solid feces towards the cloaca for excretion.

The frog's colon is quite short in comparison to its small intestine, but it is much wider!
Click on the
question mark
for the answer. Yes!
Colon What does the colon do Click on the frog's cloaca. You pee and pooh from different openings. So do most other mammals. So you might assume that all animals are similar to you, but you would be wrong.

Frogs have only ONE vent or CLOACA for both urine and feces and for reproduction.

Sharks, birds, reptiles and other amphibians are like frogs, not like you. They also have only one vent for excretions. Click on the
question mark
for the answer. Yes!
Cloaca What does the cloaca do The Glass Frog The Glass Frog - Pause to view its internal organs! Congratulations! You just explored
the digestive system of a frog. How the Digestive System Works
In Humans and in Frogs Accessory Organs in Digestion:
In both humans and frogs

there are 3
ADDITIONAL organs
important to digestion Liver
Gallbladder
Pancreas
Liver
Gallbladder
Pancreas
Now locate these accessory organs for the


inside the frog: Pancrease Gallbladder Liver DIGESTIVE SYSTEM Click on the frog's liver. The frogs has a three-lobed liver. It is the largest organ in the frog's body. Only one lobe is visible in this image. It is large, red and just below the heart on the right.

The liver produces bile which is used in the small intestines to break down fats.

The frog's liver is so large because it filters toxins from the blood. A frog's thin skin can absorb toxins easily from the environment. The liver removes such toxins from the frog's blood stream to help keep the frog healthy.

Excess liver bile is stored in a small greenish sac under the liver called the gallbladder.

The frog's pancreas makes enzymes used to digest food in the intestines. These digestive juices break down sugars, fats, proteins and starches. The pancreas is an irregular, flattened, yellowish organ near the stomach and the small intestines. Click on the
question mark
for the answer. Yes!
Liver What does the liver,
the gallbladder
and the pancreas do On to the Frog's Circulatory System Play the video to watch
the glass frog's heart beating. Now locate these parts of the


inside the frog. Arteries Lungs Heart
Veins Circulatory System Click on the frog's heart. The frog's heart pumps blood throughout its body.

The blood flows round and round. It circulates from the frog's heart, through the frog's blood vessels, back to the heart.

The heart helps to deliver oxygen to the frog's muscles, brain, digestive system and other vital organs. A frog, like all animals, must have oxygen to live.

Click on the
question mark
for the answer. Yes!
Heart What does the heart do Click on the frog's lungs. Frogs have a pair of thin-walled lungs that are almost like balloons. When frogs are out of water, they breathe air in and out through their nose, into their lungs.

Just like you, they obtain oxygen from the air they breathe in. Their lungs exchange this oxygen for carbon dioxide, which the frog breathes out.

Oxygen goes into the frog's blood stream through blood vessels in their lungs.

Frogs can also breathe through their skin. Their thin, moist skin is full of tiny blood vessels where oxygen can be absorbed from water, while carbon dioxide is released. When frogs are submerged in water, they "breathe" only through their skin, not their lungs. Frogs can even drown in poorly oxygenated water. Click on the
question mark
for the answer. Yes!
Lung What does the lungs do How Frogs Breathe: Skin, Lungs & Mouth The Anatomy of the Frog Kidneys Heart Liver Stomach Lungs Colon Eggs mass KIDNEY

The frog's kidneys filter waste products from the frog's blood. The kidneys also maintains the required balance of water, salts and other minerals in the blood. HEART

The heart is a PUMP. It pushes blood through the CIRCULATORY SYSTEM or blood vessels.

A frog's 3-chambered heart is less efficient than your 4 chambered heart. So oxygenated and deoxygenated blood tend to mix.

Frogs have three distinct circuits for blood flow. You have two. One circuit supplies oxygenated blood to their bodies. Another moves blood to the lungs to pick up oxygen. The third circuit goes to the frog's skin, so the frog can breathe through its skin. LIVER

The frog's liver is the largest organ in its body and it has three lobes.

The liver filters the nutrient rich blood coming from the digestive tract, before passing it on to the rest of the body. It helps to eliminate toxic chemicals in the blood. The liver also secretes bile that ends up back in the intestines. Bile is used to break down fats.The liver also makes proteins that are important for blood clotting.
STOMACH

Once caught and swallowed, a frog's prey is stored whole in its expanded stomach. The prey usually dies there, suffocated or drowned by the frog's stomach acids as digestion begins.

Many species of frogs can vomit out their own stomach. This allows adult frogs to expel possible toxins they may have eaten. Some frogs even give their inside-out stomach a quick scrub with their front feet! SMALL INTESTINES

The frog's small intestines is where most of the food it eats is digested and absorbed. This organ is about 10 times as long as the frog's body. This length gives the frog more time to digest and absorb nutrients from the fibrous insects, worms, small snakes and mice that it swallows whole. Small intestine Cloaca CLOACA

You pee from one opening and you poo from another. All mammals do. Frogs have ONLY ONE opening, the cloaca, where everything comes out, including the eggs from the female. Unlike you and other mammals, birds, reptiles, amphibians and most fish have only a cloaca. EGG MASS

A female frog can lay about 2500 to 3000 eggs at a time. The eggs are not fertilized until after they are excreted into the water. Colon

The colon or large intestine in frogs absorbs water from the undigested food. It stores the remaining solid waste as it moves toward the cloaca. Water and liquid waste goes to the urinary bladder, where it will also be excreted out the cloaca. LUNGS

Frogs have a pair of lungs that allows them to breathe air and survive on land. They inhale oxygen and exhale carbon dioxide using their lungs. Frogs rely on their lungs to breathe when they are active and need more oxygen than respiration through their skin can supply. (Click on the names to view the definition.) Now you know somethiing about
the insides
of a frog!
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