Problem 193 - Objective Biology for NEET

Question

Respiration in adult frog is by (a) Buccopharyngeal cavity (b) Skin (c) Lungs (d) All of these

Step-by-Step Solution

Answer

The correct answer is (d) All of these. Frogs respire through their buccopharyngeal cavity, skin, and lungs.

Step 1: Understand the Question

This question is asking which body parts does an adult frog use for respiration. The choices given are (a) Buccopharyngeal cavity, (b) Skin, (c) Lungs, and (d) All of these.

Step 2: Recall Known Information

It's known that frogs breathe using their lungs and skin, but they also use the lining of their mouth - the buccopharyngeal cavity - to absorb oxygen when they are not active.

Step 3: Choose the Correct Answer

Given this understanding of frog anatomy, the correct choice includes all the listed options. Hence, the correct answer is (d) All of these.

Key Concepts

Buccopharyngeal Cavity

Frogs have a unique respiratory system, and their buccopharyngeal cavity plays a significant role here. This cavity is essentially the area inside a frog's mouth.
Think of it as a chamber lined with a thin membrane that is full of blood vessels. These blood vessels are crucial because they allow direct gas exchange.
When a frog is at rest or submerged, it can absorb oxygen from the air that passes over this lining. This process occurs without any lung involvement.

• The buccopharyngeal cavity takes in oxygen when frogs are inactive.
• It supports the frog's need for oxygen, allowing for respiration without the lungs.
• This method is most effective when the frog is in cooler, moist conditions.

Frogs use this cavity to complement their other respiratory methods, providing an elegant solution for conserving energy.

Cutaneous Respiration

This term refers to the frog's ability to breathe through its skin. Cutaneous respiration is fascinating because it allows frogs to live both in water and on land.
A frog’s skin is thin, moist, and permeable, facilitating the exchange of gases such as oxygen and carbon dioxide between the environment and the frog's bloodstream.
For effective cutaneous respiration, the skin must remain moist at all times. Frogs often stay in damp areas or water to ensure the skin doesn't dry out.

• Skin breathing supports the frog's oxygen intake while submerged.
• In environments where other methods of respiration might be compromised, cutaneous respiration provides an advantage.
• This method is constantly happening as long as moisture levels are adequate.

Pulmonary Respiration

Pulmonary respiration in frogs involves the lungs, similar to humans. However, the mechanism by which they breathe differs slightly.
Instead of expanding a diaphragm to pull air in, frogs employ a process known as positive pressure breathing. They essentially "swallow" air into their lungs.
This method works well for when the frog is more active or needs a higher intake of oxygen, such as when they are on land.

• Involves inflating the lungs by gulping air.
• Primary method when the frog is on land and active.
• Offers an increased oxygen uptake compared to cutaneous respiration.

Amphibian Physiology

The physiology of amphibians like frogs is adapted to their dual life in water and on land.
Frogs have adapted to use three main respiratory methods: buccopharyngeal cavity, cutaneous, and pulmonary respiration. This adaptability is key to their survival and success across various environments.
Their metabolic needs change depending on the environment and activity level, so having multiple respiration methods gives them flexibility.

• Amphibians can exploit different environments more efficiently than many other vertebrates.
• This physiological flexibility helps them maintain efficient gas exchange under diverse conditions.
• It exemplifies the incredible adaptability of amphibians, allowing them to thrive where others cannot.