Cutaneous Respiration
தோல் வழி சுவாசம்
Frogs are amphibians, yet they don't rely solely on lungs. If you think lungs are the only respiratory organs in vertebrates, you are losing marks. Cutaneous respiration is the primary reason frogs survive underwater during hibernation.
The idea
In water, the frog's skin acts as an aquatic respiratory organ. Oxygen dissolved in water is exchanged through the skin via simple diffusion. This process is highly efficient due to the skin being moist and richly supplied with blood vessels. It is a passive transport mechanism requiring no ATP.
Why it matters
This exists to allow the organism to survive in aquatic environments where lungs cannot be used for gas exchange.
NEET lens
NEET focuses on the mechanism: diffusion. Remember, the skin is the respiratory organ in water, while lungs and buccal cavity function on land. Do not confuse this with pulmonary respiration. Expect questions on the 'moist skin' requirement.
Clinical significance
Cutaneous respiration requires a moist, permeable surface. If the skin dries out, the diffusion gradient for oxygen collapses, leading to asphyxiation. This is why amphibians are highly sensitive to environmental pollutants that alter skin permeability.
Introduction
Cutaneous respiration is gas exchange occurring through the moist skin of frogs, supplementing lung and buccal respiration, especially during hibernation.
Core concept
Skin characteristics enabling cutaneous respiration: moist (kept moist by mucous glands), thin, highly vascularized (dense capillary network just below skin). Importance: during hibernation underwater — entire respiration through skin. During rest: skin + lungs + buccal cavity all contribute.
Go deeper
Cutaneous respiration requires the frog to stay near water or in humid environments to keep skin moist. If skin dries, the frog suffocates. This is why frogs cannot survive long in dry environments.
From Class 10
Frogs breathe through their lungs, but they also absorb oxygen through their skin. This skin breathing is called cutaneous respiration.