Question

Amphibians, e.g., frogs respire through (a) Moist skin (b) Lungs (c) Buccopharyngeal cavity (d) All of these

Short answer

The correct answer is (d) All of these. Frogs, being amphibians, can respire through all these methods - their moist skin, lungs and buccopharyngeal cavity.

Step-by-step solution

Identify the possible ways for an amphibian to respire

Amphibians like frogs have a few ways they can respire. They can respire using their moist skin, which they tend to do when they are in water. This process is unique to amphibians.

Observe the role of lungs in respiration

Amphibians also respire using their lungs. This is a common way for vertebrates to breathe, and they do so primarily when they are on land.

Understand the buccopharyngeal cavity in respiration

Lastly, amphibians respire using the Buccopharyngeal cavity. This is another unique way amphibians breathe, using lining in their mouth and throat area to exchange gases.

Key concepts

Moist Skin Respiration

Amphibians are fascinating creatures because they have unique ways of breathing that are perfectly adapted to their environment. One of these methods is moist skin respiration. Amphibians, like frogs, have thin and permeable skin. This allows them to absorb oxygen directly from the water or air around them.
This type of respiration is especially important when they are submerged in water. The skin must remain moist for this process to be effective. When the skin is dry, oxygen cannot pass through.

• Moist skin respiration is more efficient in water than on land.
• The thin skin of amphibians is richly supplied with blood vessels to facilitate oxygen exchange.
• Mucus produced by glands helps to keep the skin moist and aid in respiration.

Despite its efficiency in water, frogs also rely on other methods when they are on land.

Lung Respiration

Frogs, along with most amphibians, use lung respiration primarily when they are on land. Lungs in amphibians are simple, balloon-like structures that can fill with air when the animal actively inhales.
Unlike more advanced vertebrates, their lungs are not as highly developed or efficient, as lung respiration is not their primary mode of breathing.

• Lungs in amphibians are relatively small compared to those of mammals.
• They rely on "positive pressure breathing" which means frogs must pump air into their lungs using their mouth and throat muscles.
• Frogs will inflate their throat pouch to help pressurize and draw air into the lungs.

This method supports amphibians when moist skin respiration is less effective, such as in dry conditions.

Buccopharyngeal Respiration

Another incredible adaptation of amphibians is buccopharyngeal respiration. This method uses the lining of the mouth and throat to facilitate gas exchange. It may sound complex, but it's a simple process that occurs even when the frog's mouth is closed.
The highly vascularized lining of the buccopharyngeal cavity allows for efficient oxygen absorption and carbon dioxide release.

• This form of breathing is constant, even when the frog is not active.
• It's a passive process that occurs between breaths taken using lungs.
• Helpful when frogs are inactive or during hibernation periods to maintain oxygen levels.

Buccopharyngeal respiration is crucial for amphibians since it complements other forms of respiration, ensuring they efficiently meet their oxygen needs.