What is Breathing?

Respiration is a biological function of living beings that consists of the exchange of gases with the external environment. As a general rule, living beings receive oxygen and release carbon dioxide.

If an organism stops breathing, it dies. Breathing serves as a primary source of energy that provides vitality to all living beings. Therefore, it is characterized by being repetitive, automatic and involuntary.

The word respiration comes from Latin I will breathe, word composed of the prefix re– indicating repetition, and the verb I will breathe which means to blow.

Types of breathing

Two types of respiration occur in living beings:

External respiration: It consists of taking oxygen from the environment, such as air or water, just as humans, animals, plants and most fungi do.

In animals, external respiration can be pulmonary, gill, tracheal or cutaneous. In plants, respiration occurs through organs found in the leaves, stems and roots.

Internal respiration or cellular respiration: It is what occurs at the level of cells and other single-celled organisms such as bacteria and yeast. It is divided into aerobic or anaerobic.

human respiration

During breathing, humans inhale or breathe in oxygen (O2) from the environment and release carbon dioxide (CO2)

Breathing in humans allows us to inhale oxygen from the air and eliminate carbon dioxide, a toxic gas produced within the body.

Like all mammals, human breathing is done through the lungs, which are part of our respiratory system. This is made up of the nasal passages, the oral cavity, the pharynx, the larynx, the trachea, the bronchi, the alveoli, the lungs and the diaphragm.

Human breathing process

The human breathing process consists of the following stages:

1. Ventilation. Ventilation consists of the circulation of air between the outside world and the lungs and, therefore, is an expression of what we call external respiration. It is made up of two steps:

Inhalation or inspiration: It is the entry of air into the lungs. Air enters through the nose, whose internal hairs clean and warm the air. It then passes through the pharynx, larynx and trachea until it reaches the lungs. The diaphragm distends downward to make room for the lungs.
Exhalation or expiration: It consists of the expulsion of air, which follows the opposite path. From the lungs it passes to the trachea, larynx, pharynx and, finally, it is expelled through the nose. The diaphragm rises, helping the lungs to exhale.

2. Hematosis. It is the exchange between oxygen and carbon dioxide that occurs in the alveoli, a type of tiny bags found at the ends of the bronchioles. The alveoli capture oxygen and transmit it to the red blood cells.

3. Transportation. Red blood cells receive oxygen from the alveoli and are responsible for distributing it throughout the bloodstream, from where it reaches the cells.

4. Internal gas exchange. The cells take the available oxygen and exchange it for carbon dioxide, which travels back through the blood to the lungs to be eliminated. This process is an example of internal or cellular respiration.

See also Carbon dioxide

animal respiration

1. Lung breathing (dog). 2. Bracheal (fish) breathing. 3. Cutaneous respiration (worm). 4. Tracheal breathing (cricket).

The structure and organs of the animal respiratory system are different in each species. Therefore, there are the following types of animal respiration: pulmonary respiration, cutaneous respiration, gill respiration and tracheal respiration.

Lung breathing. It is produced through the lungs. It is typical of mammals (including humans), birds and some reptiles and amphibians. For example, dogs, chickens, crocodiles and certain types of frogs.
Skin respiration. It is produced through the skin. It is characteristic of certain invertebrates called annelids (such as worms), echinoderms (such as the starfish), cnidarians (such as anemones) and certain amphibians (such as the salamander).
Gill respiration. It is produced through the gills, better known as gills. Vertebrate animals that live in water have gills for breathing. For example, sharks and sardines.
Tracheal breathing. It is produced through the trachea. It is typical of invertebrate animals, particularly insects. For example, dragonflies, tarantula, cricket and flea.

Most animals need oxygen to live, with the exception of three marine species known as: Spinoloricus cinzia, Rugiloricus and Pliciloricus. These animals live almost three thousand meters deep in the sea and measure about one millimeter.

You can delve into Types of Breathing.

Respiration in plants

Left: reverse of a tree leaf with detail of a stoma magnified under a microscope. Right: Stem with lenticels.

Like all living beings, plant respiration consists of capturing oxygen from the outside and releasing carbon dioxide, a process that takes place at night. It is a reverse process of photosynthesis, which consists of capturing carbon dioxide and releasing oxygen during the day.

To carry out plant respiration, in addition to oxygen, plants use sugars resulting from photosynthesis, thus obtaining energy for their growth.

The gas exchange of plant respiration occurs through the stomata and the lenticels. Stomata are cellular structures found on the back of leaves and herbaceous stems. Lenticels are distributed throughout the bark of stems and roots.

You can delve deeper into: Photosynthesis

cellular respiration

Internal respiration is the way in which cells obtain chemical energy by capturing oxygen or other molecules from the environment in which they are found.

The first phase of cellular respiration is called glycolysis and occurs in the cytoplasm of cells. The second phase of cellular respiration can be aerobic or anaerobic.

Aerobic or aerobic respiration. The word aerobic indicates the presence of oxygen. It is produced in the mitochondria of cells through oxygen.

Anaerobic or anaerobic respiration. This occurs in the absence of oxygen. It is produced in the cytoplasm of cells. The process is also called fermentation.

See also Cellular respiration.

Artificial respiration

Artificial respiration is that which assists those who are not able to breathe normally on their own. Cardiopulmonary resuscitation (CPR), for example, is an emergency artificial respiration technique.

See also: Characteristics of living beings