History of Life on the Planet
from belly to chin
and look inside . . .
something like this.
of stuff crowded together
inside that frog!
DO?
an insect with its tongue
and uses its eyeballs
to swallow the insect whole
and pushes it down
its esophagus
WHERE DOES IT GO?
down its esophagus into the STOMACH.
in stomach acids.
where it is broken down and absorbed.
the frog's cloaca, as solid feces.
or large intestine, where water is removed.
intestines
intestines
inside the frog.
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!
question mark
for the answer.
Stomach
small intestine.
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.
question mark
for the answer.
Small
Intestine
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!
question mark
for the answer.
Colon
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.
question mark
for the answer.
Cloaca
the digestive system of a frog.
there are 3
ADDITIONAL organs
important to digestion
in Human Digestion
inside the frog:
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.
question mark
for the answer.
Liver
the gallbladder
and the pancreas do
the glass frog's heart beating.
inside the frog.
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.
question mark
for the answer.
Heart
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.
question mark
for the answer.
Lung
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.
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.
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.
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!
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.
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.
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.
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.
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.
the insides
of a frog!
to return to the book.