Animal Respiration – Concept, types and examples

We explain what animal respiration is and what this process consists of. Also, the types of animal respiration that exist and examples.

Animal respiration
Animal respiration consists of an exchange of gases with the environment.

What is animal respiration?

When we speak of animal respiration, we mean to the metabolic mechanism of the living beings of the animal kingdom, consisting of an exchange of gases with the environment, in which oxygen (O2) is introduced to the body and carbon dioxide (CO2) is expelled. This process is common to all known animals, from the unicellular to the superior ones and, of course, also to the human being, although not through the same body systems, nor in the same vital environments.

Breathe in any way consists of acquiring oxygen and removing carbon dioxide, since the first gas is vital to process sugars and obtain biochemical energy to live, and the second gas is a by-product of this reaction that must be eliminated as it is harmful to the body. So all animals do it: some straight from the air, like humans and dogs; others through the water, such as fish and tadpoles.

Once oxygen enters the body as a result of animal respiration, the circulatory system is responsible for distributing it throughout the body, in order to feed the various biological tissues that need it. In this sense, the respiratory and cardiovascular systems are connected, which can be very different depending on the species of animal to which we refer.

Types of animal respiration

Animal respiration
Cutaneous respiration takes place through the skin.

There are various methods of breathing, according to the animal species and its mechanisms obtained over centuries of evolution. These mechanisms are:

  • Skin respiration As the name implies, it takes place through the skin. Some animals such as annelids (such as earthworms) and amphibians (such as frogs), especially those that live in humid environments, have thin and specialized skin, capable of capturing the desired gases from air or water and transferring them directly to the capillary system (blood vessels), releasing carbon dioxide in the same way.
  • Branchial respiration. Typical of aquatic or underwater animals, that is, they never leave the water and obtain the oxygen they need to live from it. For this they have gills, complex organs with thin walls and abundant blood vessels, which are in perpetual contact with the liquid (unlike the lungs, which are inside the body) and covered with soft, fragile and porous tissues. As the water passes through them, oxygen is filtered and carbon dioxide is released, so many fish must sleep in streams or in constant movement, in order to breathe.
  • Tracheal breathing. Typical of insects and arachnids. By trachea we mean a system of tubes that connect the interior of the animal with the exterior, through holes called stigmata. The air penetrates through them and, as the tubes become narrower, oxygen enters the cells and the hemolymph (the blood of insects), while carbon dioxide is discharged.
  • Lung breathing. Common to humans, mammals, birds, and most reptiles and amphibians, this mode of respiration works only in air, and requires internal organs called lungs, which operate like an inflatable bag: it expands when the air enters. air and deflates when it comes out. Inside there is a structure full of capillaries called alveoli, through which gas exchange occurs. Being inside the body, the lungs connect to the outside through the trachea, which then connects to the nose or mouth, and which has a series of filters along the way to retain impurities from the air.