The key difference between cutaneous and pulmonary respiration is that cutaneous respiration takes place through the skin, while pulmonary respiration takes place through the lungs.
There are two types of respiration as internal respiration and external respiration. Internal respiration refers to cellular respiration that produces energy or ATP. External respiration refers to pulmonary respiration or breathing, which involves inhalation and exhalation. Pulmonary respiration takes place in the respiratory system. It is the process of exchanging oxygen and carbon dioxide at the alveoli. Cutaneous respiration is also a type of external respiration. However, in cutaneous respiration, gaseous exchange occurs through the skin.
CONTENTS
1. Overview and Key Difference
2. What is Cutaneous Respiration
3. What is Pulmonary Respiration
4. Similarities Between Cutaneous and Pulmonary Respiration
5. Side by Side Comparison – Cutaneous vs Pulmonary Respiration in Tabular Form
6. Summary
What is Cutaneous Respiration?
Cutaneous respiration is the gas exchange occurring through skin or body surface, instead of lungs or gills. In some animals, cutaneous respiration works as the sole method of gas exchange while in some animals, it works as a secondary mode of respiration. This kind of respiration is seen in organisms such as insects, amphibians, fish, sea snakes, turtles, etc. In mammals, cutaneous respiration can be seen to a lesser extent. Even in humans, 2 to 3% gas exchange occurs through skin although the pulmonary respiration is the sole respiration seen in humans.
Figure 01: Cutaneous Respiration
Cutaneous respiration operates in both air and water. Moreover, it occurs continuously unlike pulmonary respiration. During diving, O2 uptake is high through cutaneous respiration than through pulmonary respiration.
What is Pulmonary Respiration?
Pulmonary respiration is the gas exchange that occurs in the lungs. There are two processes occurring in pulmonary respiration as inhalation and exhalation. By inhalation, we bring air into the lungs, while by exhalation, we release air to the atmosphere.
Figure 02: Pulmonary Respiration
The air we breathe goes through the pulmonary capillaries and oxygen diffuses into the blood there. Moreover, carbon dioxide diffuses back into the alveolar gas. Then we exhale this carbon dioxide-containing air from the body to the outside.
What are the Similarities Between Cutaneous and Pulmonary Respiration?
- Cutaneous and pulmonary respiration are two types of external respiration shown by the living organisms.
- Both are diffusion-based gas flux.
What is the Difference Between Cutaneous and Pulmonary Respiration?
Cutaneous respiration is the gas exchange that occurs via the skin or body surface of animals, while pulmonary respiration is the gas exchange that occurs via the alveoli in the lungs. So, this is the key difference between cutaneous and pulmonary respiration. Cutaneous respiration is seen in amphibians, insects, fish and reptiles, while pulmonary respiration is mainly seen in mammals. Moreover, cutaneous respiration takes place continuously and operates both in water and air, unlike pulmonary respiration.
The below infographic summarizes the difference between cutaneous and pulmonary respiration.
Summary – Cutaneous vs Pulmonary Respiration
Respiration is the gas exchange or the process by which oxygen and carbon dioxide diffuse in and out of the blood. When the gaseous exchange occurs through the skin, it is known as cutaneous respiration. In contrast, the gas exchange that occurs through the membranes of the lungs is known as pulmonary respiration. In fact, pulmonary respiration is the main mode of respiration in most animals, while cutaneous respiration is the secondary mode of respiration. Thus, this summarizes the difference between cutaneous and pulmonary respiration.
Reference:
1. “Pulmonary Alveolus.” Wikipedia, Wikimedia Foundation, 23 Nov. 2019, Available here.
Image Courtesy:
1. “Telmatobius culeus” By Samuel Garman (1843-1927) – Exploration of Lake Titicaca by Alexander Agassiz and S. W. Garman. I. Fishes and Reptiles. Bulletin of the Museum of Comparative Zoology, vol. 3, n. 11, p. 273-279, Public Domain) via Commons Wikimedia
2. “Gas exchange in the aveolus” By domdomegg – Own work (CC BY 4.0) via Commons Wikimedia